|
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Hi there,
Anyone have or used one of these antenna tuners? Wondering how they perform, have read the reviews on eham ect, just looking for other opinions. TIA Richard |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Richard,
Considering some of the reviews I've seen on various forums, the one thing those reviews proves is that they must work. How well they work just depends on how close to the tuner's limits any particular antenna falls. 'Size' is one consideration that isn't thought of very often. Bigger usually means larger limits cuz all those thingys inside are larger, which is good to some ridiculous point. Deciding where 'ridiculous' starts/stops depends on you to a large extent. It has to do with the antennas you have/want/are allowed, and the size of your bank account. Is it the mostest best thing on the market? Good question, and another one of those 'depends' thingys. (Mine is the bestest tuner ever made. It isn't produced anymore. It is not for sale, wish I had another one! Can do some really 'weird' antennas. Ain't saying what it is so the price will be cheaper when I find another one.) - 'Doc [Large doses of 'B.S.' are always a part of my responses. Deciding which is what is your responsibility. Hows that for a 'CYA'?] |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Richard,
My Palstar AT1KP arrived this morning, so early days yet. What I can say about it is that the build quality inside and out looks excellent. I have only run 110 watts through it and it has tuned my 40m Centre Fed Dipole cut for 40 meters down to 1.1: from 1.8 - 6 meters with ease. Hope this helps. 73 Andy wrote in message ... Richard, Considering some of the reviews I've seen on various forums, the one thing those reviews proves is that they must work. How well they work just depends on how close to the tuner's limits any particular antenna falls. 'Size' is one consideration that isn't thought of very often. Bigger usually means larger limits cuz all those thingys inside are larger, which is good to some ridiculous point. Deciding where 'ridiculous' starts/stops depends on you to a large extent. It has to do with the antennas you have/want/are allowed, and the size of your bank account. Is it the mostest best thing on the market? Good question, and another one of those 'depends' thingys. (Mine is the bestest tuner ever made. It isn't produced anymore. It is not for sale, wish I had another one! Can do some really 'weird' antennas. Ain't saying what it is so the price will be cheaper when I find another one.) - 'Doc [Large doses of 'B.S.' are always a part of my responses. Deciding which is what is your responsibility. Hows that for a 'CYA'?] |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Hi Richard,
Just an update for you on my AT1KP tuner. I am only running 110 watts through the tuner due to not owning an Amplifier. I have tried it out on an End Fed wire WITH an earth ground rod that has a very poor ground and also an End Fed Zep. It still tunes these wires down to 1.1:1 from 160 - 6 Meters with ease. I am very pleased with it and I'm glade I purchased the AT1KP. Hope this helps. 73 Andy "Andy" wrote in message ... Richard, My Palstar AT1KP arrived this morning, so early days yet. What I can say about it is that the build quality inside and out looks excellent. I have only run 110 watts through it and it has tuned my 40m Centre Fed Dipole cut for 40 meters down to 1.1: from 1.8 - 6 meters with ease. Hope this helps. 73 Andy wrote in message ... Richard, Considering some of the reviews I've seen on various forums, the one thing those reviews proves is that they must work. How well they work just depends on how close to the tuner's limits any particular antenna falls. 'Size' is one consideration that isn't thought of very often. Bigger usually means larger limits cuz all those thingys inside are larger, which is good to some ridiculous point. Deciding where 'ridiculous' starts/stops depends on you to a large extent. It has to do with the antennas you have/want/are allowed, and the size of your bank account. Is it the mostest best thing on the market? Good question, and another one of those 'depends' thingys. (Mine is the bestest tuner ever made. It isn't produced anymore. It is not for sale, wish I had another one! Can do some really 'weird' antennas. Ain't saying what it is so the price will be cheaper when I find another one.) - 'Doc [Large doses of 'B.S.' are always a part of my responses. Deciding which is what is your responsibility. Hows that for a 'CYA'?] |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Andy, is your endfed wire the one in your other thread of the 8th June
(ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes Hi Richard, Just an update for you on my AT1KP tuner. I am only running 110 watts through the tuner due to not owning an Amplifier. I have tried it out on an End Fed wire WITH an earth ground rod that has a very poor ground and also an End Fed Zep. It still tunes these wires down to 1.1:1 from 160 - 6 Meters with ease. I am very pleased with it and I'm glade I purchased the AT1KP. Hope this helps. 73 Andy -- Ian |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Hi Ian,
Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes Hi Richard, Just an update for you on my AT1KP tuner. I am only running 110 watts through the tuner due to not owning an Amplifier. I have tried it out on an End Fed wire WITH an earth ground rod that has a very poor ground and also an End Fed Zep. It still tunes these wires down to 1.1:1 from 160 - 6 Meters with ease. I am very pleased with it and I'm glade I purchased the AT1KP. Hope this helps. 73 Andy -- Ian |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
In message , Andy
writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the twin feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Ian,
I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the twin feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Andy wrote:
Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the twin feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian adding a suitably cut wire counterpoise at +% for each band should certainly assist things . |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
In message , atec77
writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Ian Jackson wrote:
In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. of course he can , he has a run of crap coax so when he replaces it with some rg213 adding some multi strand suitably trimmed one be a burden from the far coax connection back A decent earthing system should work maybe there is a reason to not have one , with more description a balun of some sort may prove most useful (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. rg 58cu ? is kinda crap :) Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Oh dear Finally, can I ask you to follow the standard practice of bottom posting! Cheers... |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Oh, I think under the circumstances, that RG-58 isn't all that bad.
May not have the lowest losses possible, but certainly not complete 'crap'. Replacing it with something 'better' is certainly an option, but not the first one I'd try. Options. Try all that you can think of and see what happens. If things are 'better' on one particular band doing it 'this' way, then I think I'd note that when using that particular band. Repeat for the other bands. Lots of work? Sure, but if it works, it works. Finding one antenna that does it all is almost impossible. Too many variables depending on each individual installation. But, if you get 'close', that's probably as good as you can expect, depending on the circumstances. Having the absolute 'best' antenna in the world is certainly nice! It isn't absolutely necessary. Everyone goes through this same sort of thingy. The results differ, but so do the circumstances. Good luck. - 'Doc |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
"Ian Jackson" wrote in message ... In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian I've have just connected the Analyser at the feed point on the End fed wire. The frequency is now at 2.898 MHz without coax being in line. I have just tried to shorten the Antenna again to bring the frequency closer to the 80m band, but it will not adjust from this frequency. What's confusing me is that the End fed wire should be longer than a 1/4 wave on 80 and the frequency that it ended up on, that is now 2.898 would be about right for the length. So why won't that frequency change when I start trimming the wire down in size? It just isn't making any sense to me. The resonant frequency surely should change with the altered length. 73 Andy |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
In message , Andy
writes "Ian Jackson" wrote in message ... In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian I've have just connected the Analyser at the feed point on the End fed wire. The frequency is now at 2.898 MHz without coax being in line. I have just tried to shorten the Antenna again to bring the frequency closer to the 80m band, but it will not adjust from this frequency. Ummmm... Obviously something is wrong. It looks like your analyser is simply telling lies. Could it have a spurious resonance at this frequency? What's confusing me is that the End fed wire should be longer than a 1/4 wave on 80 and the frequency that it ended up on, that is now 2.898 would be about right for the length. A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit on the short side. Being only 20 feet up may pull the resonance a bit lower, but I doubt is could be anywhere as low as 2.898MHz. So why won't that frequency change when I start trimming the wire down in size? It just isn't making any sense to me. The resonant frequency surely should change with the altered length. If shortening the aerial doesn't change the frequency, I don't think your analyser is measuring the aerial. This is indeed a puzzle. As I suggested before, you could go from the sublime to the ridiculous, and try something like 33 feet, which should resonate at around 7MHz. If it sticks at 2.898MHz, something is seriously amiss. -- Ian |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
"Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian I've have just connected the Analyser at the feed point on the End fed wire. The frequency is now at 2.898 MHz without coax being in line. I have just tried to shorten the Antenna again to bring the frequency closer to the 80m band, but it will not adjust from this frequency. Ummmm... Obviously something is wrong. It looks like your analyser is simply telling lies. Could it have a spurious resonance at this frequency? What's confusing me is that the End fed wire should be longer than a 1/4 wave on 80 and the frequency that it ended up on, that is now 2.898 would be about right for the length. A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit on the short side. Being only 20 feet up may pull the resonance a bit lower, but I doubt is could be anywhere as low as 2.898MHz. So why won't that frequency change when I start trimming the wire down in size? It just isn't making any sense to me. The resonant frequency surely should change with the altered length. If shortening the aerial doesn't change the frequency, I don't think your analyser is measuring the aerial. This is indeed a puzzle. As I suggested before, you could go from the sublime to the ridiculous, and try something like 33 feet, which should resonate at around 7MHz. If it sticks at 2.898MHz, something is seriously amiss. -- Ian MFJ Analyser ???? Isolate the transmission line (coax) from the antenna, ie; UGLY BALUN, Line Isolator analyser may have copted a nose full of RF from the braid of feedline, with such a mismatch should build resonant antennas first, before inserting giant matcher, just to see how much of your RF is dissipated in the match box. TX and RX |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
I haven't had time to try a 33" End fed to see if it would tune on 40m .But
I did have time to connect a temp 60 feet of wire from the top of the ribbon feeder on the braid side to make a close 63 feet centre fed dipole fed with 300 Ohm feeder and the antenna resonates at 3.780 MHz with a 1.1:1 and the AT1KP backs this reading up. I haven't tried to lengthen or shorten the antenna yet. To see if it changes resonance, but I will do tomorrow. It can't stay like that unfortunately. So either my Analyser doesn't like to read End Fed antennas or there something else causing the funny readings. If the Analyser senses the change in frequency tomorrow when I start lengthening the antenna then it must be working OK or there is a fault with it and it can't read End Fed wires correctly. Is this even possible considering its reading everything else correct. What do you think? 73 Andy "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian I've have just connected the Analyser at the feed point on the End fed wire. The frequency is now at 2.898 MHz without coax being in line. I have just tried to shorten the Antenna again to bring the frequency closer to the 80m band, but it will not adjust from this frequency. Ummmm... Obviously something is wrong. It looks like your analyser is simply telling lies. Could it have a spurious resonance at this frequency? What's confusing me is that the End fed wire should be longer than a 1/4 wave on 80 and the frequency that it ended up on, that is now 2.898 would be about right for the length. A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit on the short side. Being only 20 feet up may pull the resonance a bit lower, but I doubt is could be anywhere as low as 2.898MHz. So why won't that frequency change when I start trimming the wire down in size? It just isn't making any sense to me. The resonant frequency surely should change with the altered length. If shortening the aerial doesn't change the frequency, I don't think your analyser is measuring the aerial. This is indeed a puzzle. As I suggested before, you could go from the sublime to the ridiculous, and try something like 33 feet, which should resonate at around 7MHz. If it sticks at 2.898MHz, something is seriously amiss. -- Ian |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Albert,
I will tomorrow see if I have a spare 21" of coax handy to make one. 73 Andy "Albert" wrote in message node... "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian I've have just connected the Analyser at the feed point on the End fed wire. The frequency is now at 2.898 MHz without coax being in line. I have just tried to shorten the Antenna again to bring the frequency closer to the 80m band, but it will not adjust from this frequency. Ummmm... Obviously something is wrong. It looks like your analyser is simply telling lies. Could it have a spurious resonance at this frequency? What's confusing me is that the End fed wire should be longer than a 1/4 wave on 80 and the frequency that it ended up on, that is now 2.898 would be about right for the length. A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit on the short side. Being only 20 feet up may pull the resonance a bit lower, but I doubt is could be anywhere as low as 2.898MHz. So why won't that frequency change when I start trimming the wire down in size? It just isn't making any sense to me. The resonant frequency surely should change with the altered length. If shortening the aerial doesn't change the frequency, I don't think your analyser is measuring the aerial. This is indeed a puzzle. As I suggested before, you could go from the sublime to the ridiculous, and try something like 33 feet, which should resonate at around 7MHz. If it sticks at 2.898MHz, something is seriously amiss. -- Ian MFJ Analyser ???? Isolate the transmission line (coax) from the antenna, ie; UGLY BALUN, Line Isolator analyser may have copted a nose full of RF from the braid of feedline, with such a mismatch should build resonant antennas first, before inserting giant matcher, just to see how much of your RF is dissipated in the match box. TX and RX |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
In message , Albert
writes "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian I've have just connected the Analyser at the feed point on the End fed wire. The frequency is now at 2.898 MHz without coax being in line. I have just tried to shorten the Antenna again to bring the frequency closer to the 80m band, but it will not adjust from this frequency. Ummmm... Obviously something is wrong. It looks like your analyser is simply telling lies. Could it have a spurious resonance at this frequency? What's confusing me is that the End fed wire should be longer than a 1/4 wave on 80 and the frequency that it ended up on, that is now 2.898 would be about right for the length. A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit on the short side. Being only 20 feet up may pull the resonance a bit lower, but I doubt is could be anywhere as low as 2.898MHz. So why won't that frequency change when I start trimming the wire down in size? It just isn't making any sense to me. The resonant frequency surely should change with the altered length. If shortening the aerial doesn't change the frequency, I don't think your analyser is measuring the aerial. This is indeed a puzzle. As I suggested before, you could go from the sublime to the ridiculous, and try something like 33 feet, which should resonate at around 7MHz. If it sticks at 2.898MHz, something is seriously amiss. -- Ian MFJ Analyser ???? Isolate the transmission line (coax) from the antenna, ie; UGLY BALUN, Line Isolator analyser may have copted a nose full of RF from the braid of feedline, with such a mismatch should build resonant antennas first, before inserting giant matcher, just to see how much of your RF is dissipated in the match box. TX and RX Unless I mis-read something, Andy says that he tried the analyser directly on the antenna (at the antenna feedpoint) - so no coax was involved in this particular test. He seems to get a resonance at 2.898MHz, regardless of the length of the antenna. Could this be because there is a strong (and permanent) RF signal which is being picked up on the antenna, and is confusing the analyser? -- Ian |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
"Andy" wrote in message ... I haven't had time to try a 33" End fed to see if it would tune on 40m .But I did have time to connect a temp 60 feet of wire from the top of the ribbon feeder on the braid side to make a close 63 feet centre fed dipole fed with 300 Ohm feeder and the antenna resonates at 3.780 MHz with a 1.1:1 and the AT1KP backs this reading up. I haven't tried to lengthen or shorten the antenna yet. To see if it changes resonance, but I will do tomorrow. It can't stay like that unfortunately. So either my Analyser doesn't like to read End Fed antennas or there something else causing the funny readings. If the Analyser senses the change in frequency tomorrow when I start lengthening the antenna then it must be working OK or there is a fault with it and it can't read End Fed wires correctly. Is this even possible considering its reading everything else correct. What do you think? 73 Andy "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian I've have just connected the Analyser at the feed point on the End fed wire. The frequency is now at 2.898 MHz without coax being in line. I have just tried to shorten the Antenna again to bring the frequency closer to the 80m band, but it will not adjust from this frequency. Ummmm... Obviously something is wrong. It looks like your analyser is simply telling lies. Could it have a spurious resonance at this frequency? What's confusing me is that the End fed wire should be longer than a 1/4 wave on 80 and the frequency that it ended up on, that is now 2.898 would be about right for the length. A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit on the short side. Being only 20 feet up may pull the resonance a bit lower, but I doubt is could be anywhere as low as 2.898MHz. So why won't that frequency change when I start trimming the wire down in size? It just isn't making any sense to me. The resonant frequency surely should change with the altered length. If shortening the aerial doesn't change the frequency, I don't think your analyser is measuring the aerial. This is indeed a puzzle. As I suggested before, you could go from the sublime to the ridiculous, and try something like 33 feet, which should resonate at around 7MHz. If it sticks at 2.898MHz, something is seriously amiss. -- Ian yes tricky, have you done the ZO test on the RG-58 ? using the test gear at the freqs you discribe, 10 turns rg-213 @ 10 " hence UGLY less as you go up the band, or 12 x77 type ferrite beads close proximity Stray RF, CONNECTED OR NOT and direct sunlight on the meter face ( summer for a period of time ) are two sure ways to Kill a MFJ analyser |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
In message , Andy
writes "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian I've have just connected the Analyser at the feed point on the End fed wire. The frequency is now at 2.898 MHz without coax being in line. I have just tried to shorten the Antenna again to bring the frequency closer to the 80m band, but it will not adjust from this frequency. Ummmm... Obviously something is wrong. It looks like your analyser is simply telling lies. Could it have a spurious resonance at this frequency? What's confusing me is that the End fed wire should be longer than a 1/4 wave on 80 and the frequency that it ended up on, that is now 2.898 would be about right for the length. A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit on the short side. Being only 20 feet up may pull the resonance a bit lower, but I doubt is could be anywhere as low as 2.898MHz. So why won't that frequency change when I start trimming the wire down in size? It just isn't making any sense to me. The resonant frequency surely should change with the altered length. If shortening the aerial doesn't change the frequency, I don't think your analyser is measuring the aerial. This is indeed a puzzle. As I suggested before, you could go from the sublime to the ridiculous, and try something like 33 feet, which should resonate at around 7MHz. If it sticks at 2.898MHz, something is seriously amiss. -- Ian I haven't had time to try a 33" End fed to see if it would tune on 40m .But I did have time to connect a temp 60 feet of wire from the top of the ribbon feeder on the braid side to make a close 63 feet centre fed dipole fed with 300 Ohm feeder and the antenna resonates at 3.780 MHz with a 1.1:1 and the AT1KP backs this reading up. I haven't tried to lengthen or shorten the antenna yet. To see if it changes resonance, but I will do tomorrow. It can't stay like that unfortunately. So either my Analyser doesn't like to read End Fed antennas or there something else causing the funny readings. If the Analyser senses the change in frequency tomorrow when I start lengthening the antenna then it must be working OK or there is a fault with it and it can't read End Fed wires correctly. Is this even possible considering its reading everything else correct. What do you think? 73 Andy Andy, you've gone back to top posting, and this makes it very difficult to follow the discussion. In newsgroups (unlike emails), you should really post at the bottom. This is the established convention. Anyway, it's interesting what you have found out with the dipole configuration. Presumably, you still have the coax braid and one side of 300 ohm feeder earthed. If so, I would not have expected there to be quite such a dramatic change of resonance. However, if your earth rods are totally ineffective (or you have disconnected the earth), you might expect things to change a lot when you add 'the other half of the dipole'. If you actually have room to put up an appx 60 foot + 60 foot dipole, why not consider a G5RV (which, I believe, you have already tried) or a W3DZZ trap dipole? This would get rid of your earthing problems. -- Ian |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
"Ian Jackson" wrote in message ... In message , Albert writes "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian I've have just connected the Analyser at the feed point on the End fed wire. The frequency is now at 2.898 MHz without coax being in line. I have just tried to shorten the Antenna again to bring the frequency closer to the 80m band, but it will not adjust from this frequency. Ummmm... Obviously something is wrong. It looks like your analyser is simply telling lies. Could it have a spurious resonance at this frequency? What's confusing me is that the End fed wire should be longer than a 1/4 wave on 80 and the frequency that it ended up on, that is now 2.898 would be about right for the length. A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit on the short side. Being only 20 feet up may pull the resonance a bit lower, but I doubt is could be anywhere as low as 2.898MHz. So why won't that frequency change when I start trimming the wire down in size? It just isn't making any sense to me. The resonant frequency surely should change with the altered length. If shortening the aerial doesn't change the frequency, I don't think your analyser is measuring the aerial. This is indeed a puzzle. As I suggested before, you could go from the sublime to the ridiculous, and try something like 33 feet, which should resonate at around 7MHz. If it sticks at 2.898MHz, something is seriously amiss. -- Ian MFJ Analyser ???? Isolate the transmission line (coax) from the antenna, ie; UGLY BALUN, Line Isolator analyser may have copted a nose full of RF from the braid of feedline, with such a mismatch should build resonant antennas first, before inserting giant matcher, just to see how much of your RF is dissipated in the match box. TX and RX Unless I mis-read something, Andy says that he tried the analyser directly on the antenna (at the antenna feedpoint) - so no coax was involved in this particular test. He seems to get a resonance at 2.898MHz, regardless of the length of the antenna. Could this be because there is a strong (and permanent) RF signal which is being picked up on the antenna, and is confusing the analyser? -- Ian Yes , could be a product of a Broadcast station ? ok on the NO COAX, unless damage has been done. tricky, will keep you off the streets, and out of the pubs Andy, or perhaps in the pubs full as a boot if you do not get some answers soon good luck |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
Ian Jackson wrote:
In message , Albert writes "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian I've have just connected the Analyser at the feed point on the End fed wire. The frequency is now at 2.898 MHz without coax being in line. I have just tried to shorten the Antenna again to bring the frequency closer to the 80m band, but it will not adjust from this frequency. Ummmm... Obviously something is wrong. It looks like your analyser is simply telling lies. Could it have a spurious resonance at this frequency? What's confusing me is that the End fed wire should be longer than a 1/4 wave on 80 and the frequency that it ended up on, that is now 2.898 would be about right for the length. A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit on the short side. Being only 20 feet up may pull the resonance a bit lower, but I doubt is could be anywhere as low as 2.898MHz. So why won't that frequency change when I start trimming the wire down in size? It just isn't making any sense to me. The resonant frequency surely should change with the altered length. If shortening the aerial doesn't change the frequency, I don't think your analyser is measuring the aerial. This is indeed a puzzle. As I suggested before, you could go from the sublime to the ridiculous, and try something like 33 feet, which should resonate at around 7MHz. If it sticks at 2.898MHz, something is seriously amiss. -- Ian MFJ Analyser ???? Isolate the transmission line (coax) from the antenna, ie; UGLY BALUN, Line Isolator analyser may have copted a nose full of RF from the braid of feedline, with such a mismatch should build resonant antennas first, before inserting giant matcher, just to see how much of your RF is dissipated in the match box. TX and RX Unless I mis-read something, Andy says that he tried the analyser directly on the antenna (at the antenna feedpoint) - so no coax was involved in this particular test. He seems to get a resonance at 2.898MHz, regardless of the length of the antenna. Could this be because there is a strong (and permanent) RF signal which is being picked up on the antenna, and is confusing the analyser? or a faulty fitting , time to check things with a multimeter to eliminate a short |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
"Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... In message , atec77 writes Andy wrote: "Ian Jackson" wrote in message ... In message , Andy writes "Ian Jackson" wrote in message ... Andy, is your endfed wire the one in your other thread of the 8th June (ie the 80 Meter End Fed, fed with coax at the far end)? If so, presumably the tuner is at the shack end. Or are you feeding it from the shack end. In message , Andy writes -- Hi Ian, Yes its the same. The tuner is at the shack end (house) and I'm feeding the antenna with 50 Ohm RG-58 C/U coax at the far end of the garden. If I can get it working well I will replace it with some RG-213 that I have here. I put it back up yesterday and started experimenting again. The End Fed at the moment has 15 feet of 300 Ohm slotted ribbon feeder. This is all I had left spare. One side is connected to the wire antenna and the other side left, not connected. The coax is connected to the 300 Ohm at the bottom and the braid side is now connected to the unconnected side of the 300 Ohm and also to the earth ground rod. On 80 the receive is up 2-4 S points compared with the 40m coax Centre Fed Dipole. I have not had chance to get any actual reports on 80 yet. Maybe this weekend. 73 Andy OK, Andy. Noted. I don't know if you will really improve things by using the 15 foot of 300 ohm feeder. It's a sort of a zepp, but with one side of the feeder earthed. I would try disconnecting the earthed ('unconnected') side from earth / coax braid. You can either leave it floating, or connect it to the coax inner. It will then be approximately a quarterwave on 20m, fed in parallel with the long wire. Don't read too much into the excellent SWR you're getting with the tuner. That's what the TX sees, but the tuner can't affect the SWR on the aerial feeder. If the coax SWR is sky high (and it can be if the impedance at aerial feed point is high), the coax losses will be much more that you would get compared with when it is matched correctly. You only get away with it by using the lowest-loss you can find, and keeping the coax as short as possible. I'm not surprised that 80m on the endfed is a bit better than the 40m dipole. But what's 40m like on the endfed? That's when the feed impedance (and coax SWR) will be very high, and where the RG-213 might perform better noticeably better than the RG-58. As I think I said before, although I am an advocate of simply using coax (regardless), after all these years I am considering in investing in something like a SG230 remote tuner for the far end of the coax. -- Ian Ian, I'll have to do some experimenting with the 300 Ohm feeder and see what happens. The End Fed on 40m is very poor indeed. I would say unusable like it is. The End Fed wire at the moment is resonate on 2. 682 MHz. The funny thing is that when I cut the wire to bring the End Fed to resonate on 80m, no matter how much wire I cut off it doesn't really move from the 2.682 MHz. I have tried this with and with out the ribbon feeder being in place and with coax connected direct and the braid connected to the earth rod. What would cause this? I have no problem using the Analyser with my mobile and centre fed dipoles. 73 Andy adding a suitably cut wire counterpoise at +% for each band should certainly assist things . I rather think that Andy can't add counterpoises. A decent earthing system should work (although additional counterpoises certainly won't do any harm). Re the 2.682MHz resonance, this may be because the coax is completely mismatched at lots of frequencies, and what you're seeing this is more-or-less a spurious resonance of the coax itself. Do you still get it with the wire completely disconnected? Even with centre-fed dipoles, you often get some very unexpected resonances way off frequency (especially of you are doing a wideband frequency sweep of the return loss / SWR). As I said previously, persuading an approximate halfwave endfed (which is what you have on 40m) to work with a coax feed is certainly not ideal, but you can usually get it to work fairly well (with all the provisos already discussed). My setup here is almost twice the size of what you have, so the wire feed impedance will be low on 160m and I high on 80m and 40m. 80m (corresponding to your 40m) is certainly lively enough. On 40m, the performance does not seem to be unduly poor compared with the signal reports swapped between others on the band. So, Andy, I simply don't know why your 40m is so poor. Have you tried (temporarily) reducing the length to around 33 feet, so that it is a quarterwave on 40m? This should give a reasonable match for your coax (at least, nothing you can't tune out back in the shack). If this is more lively than the 64 feet, maybe you can try two wires in parallel. This can be discussed later if the 33 feet shows promise. If a multiband (and possibly compromise) aerial doesn't work well, it's a good idea to try something simple which you know SHOULD work. The problem may lie elsewhere. Finally, can I ask you to follow the standard practice of bottom posting! Cheers... -- Ian I've have just connected the Analyser at the feed point on the End fed wire. The frequency is now at 2.898 MHz without coax being in line. I have just tried to shorten the Antenna again to bring the frequency closer to the 80m band, but it will not adjust from this frequency. Ummmm... Obviously something is wrong. It looks like your analyser is simply telling lies. Could it have a spurious resonance at this frequency? What's confusing me is that the End fed wire should be longer than a 1/4 wave on 80 and the frequency that it ended up on, that is now 2.898 would be about right for the length. A quarterwave on 80m is around 66 feet. Your 63 feet is actually a bit on the short side. Being only 20 feet up may pull the resonance a bit lower, but I doubt is could be anywhere as low as 2.898MHz. So why won't that frequency change when I start trimming the wire down in size? It just isn't making any sense to me. The resonant frequency surely should change with the altered length. If shortening the aerial doesn't change the frequency, I don't think your analyser is measuring the aerial. This is indeed a puzzle. As I suggested before, you could go from the sublime to the ridiculous, and try something like 33 feet, which should resonate at around 7MHz. If it sticks at 2.898MHz, something is seriously amiss. -- Ian I haven't had time to try a 33" End fed to see if it would tune on 40m .But I did have time to connect a temp 60 feet of wire from the top of the ribbon feeder on the braid side to make a close 63 feet centre fed dipole fed with 300 Ohm feeder and the antenna resonates at 3.780 MHz with a 1.1:1 and the AT1KP backs this reading up. I haven't tried to lengthen or shorten the antenna yet. To see if it changes resonance, but I will do tomorrow. It can't stay like that unfortunately. So either my Analyser doesn't like to read End Fed antennas or there something else causing the funny readings. If the Analyser senses the change in frequency tomorrow when I start lengthening the antenna then it must be working OK or there is a fault with it and it can't read End Fed wires correctly. Is this even possible considering its reading everything else correct. What do you think? 73 Andy Andy, you've gone back to top posting, and this makes it very difficult to follow the discussion. In newsgroups (unlike emails), you should really post at the bottom. This is the established convention. Anyway, it's interesting what you have found out with the dipole configuration. Presumably, you still have the coax braid and one side of 300 ohm feeder earthed. If so, I would not have expected there to be quite such a dramatic change of resonance. However, if your earth rods are totally ineffective (or you have disconnected the earth), you might expect things to change a lot when you add 'the other half of the dipole'. If you actually have room to put up an appx 60 foot + 60 foot dipole, why not consider a G5RV (which, I believe, you have already tried) or a W3DZZ trap dipole? This would get rid of your earthing problems. -- Ian How I got the extra 60 feet + up was to bring it back on itself towards the house in a shape of the letter V. The wire is very low to the floor and in every ones way. I have no idea how it radiates in this shape. It can only be like this as a temp solution. I really need to understand why the End Fed wire is behaving the way it does. I think the Analyser is working OK or it wouldn't be able to tune a Centre Fed Dipole. I hope When the earth rod was connected to the End Fed wire as a ground, there was a definite 2 S points up on received signal compared to it being disconnected. So it must be doing something. I had a listen around 2 - 3.5 MHz for any strong signals and I can't find any that might cause me problems. I would have expected the frequency to change when altering the length of the wire. 73 Andy. |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
In message , Andy
writes "Ian Jackson" wrote in message ... Anyway, it's interesting what you have found out with the dipole configuration. Presumably, you still have the coax braid and one side of 300 ohm feeder earthed. If so, I would not have expected there to be quite such a dramatic change of resonance. However, if your earth rods are totally ineffective (or you have disconnected the earth), you might expect things to change a lot when you add 'the other half of the dipole'. If you actually have room to put up an appx 60 foot + 60 foot dipole, why not consider a G5RV (which, I believe, you have already tried) or a W3DZZ trap dipole? This would get rid of your earthing problems. -- Ian How I got the extra 60 feet + up was to bring it back on itself towards the house in a shape of the letter V. The wire is very low to the floor and in every ones way. I have no idea how it radiates in this shape. It can only be like this as a temp solution. I really need to understand why the End Fed wire is behaving the way it does. I think the Analyser is working OK or it wouldn't be able to tune a Centre Fed Dipole. I hope When the earth rod was connected to the End Fed wire as a ground, there was a definite 2 S points up on received signal compared to it being disconnected. So it must be doing something. True. I had a listen around 2 - 3.5 MHz for any strong signals and I can't find any that might cause me problems. Noted. I would have expected the frequency to change when altering the length of the wire. 73 Andy. What you have done is essentially to add a counterpoise / radial which is appx a quarterwave long. This is really the other half of the dipole. The higher it is up in the air, the more it will radiate. Note that, as it is at the top end of the 15 feet of 300 ohm feeder, the feeder will act like a transformer, and couple RF into 'counterpoise'. The 'counterpoise' will be more lively than if it were connected to the braid at the far end of the coax. As the 'counterpoise' is coming back under the actual aerial wire (albeit at an angle) the radiation will tend to oppose that from the aerial. This will reduce the overall radiation, so the greater the separation, the better. [Of course, if the counterpoise can be run in the opposite direction from the aerial wire, the radiation doesn't cancel, and you might as well erect the counterpoise as high as possible. What you will have, of course, is a 'normal' dipole.] I still think all of this points to the fact that your earth rods are making very poor contact with the ground. If you have a fantastic earth connection, counterpoises and radials have little effect. With an absolutely lousy ground contact (and poor ground conductivity), they can make a great difference. With the single wire (and no counterpoise), the analyser will need a good earth connection. Without it, it's going to read rubbish, which may explain why a change of wire length makes no difference. I think I would concentrate on improving the ground connection a bit more (more earth rods, or maybe some wires buried in the ground?). My inverted-L aerial feed is at the fence at the end of my back garden. The earthing system (at the fence) consists of three old bits of galvanized water pipe (about 6 foot long), and each about 6 feet apart. In addition to that, the wooden fence posts are mounted into 'Metposts' http://www.metpost.co.uk/ each of which is about around 2.5 foot long, with only about 6 inches above the ground. The length of the fence is 70 feet, so there about Metposts. Most of these are also connected to my earthing system. I did once try adding a counterpoise for 80m, but it had no effect. [My soil, by the way, is mainly clay and flints. That which is not, is old bricks.] When you've done as much as is reasonable with you earth system, all you can do is to add counterpoises etc. If you really cannot get an efficient earth/counterpoise system, you will probably be better concentrating your efforts on dipoles (even if you have to use bent or compressed versions). At least you know where you are with a dipole. -- Ian |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
It may once have been an established convention to bottom post - these days
many people don't bother unless there is a specific need to reference particular comments in multiple parts of a posting. May be irritating for some, but build a bridge and get over it. A more serious PITA is people not trimming the unnecessary parts from their responses when there is no requirement to include it. If people really want to have a look at how the discussion plays out, then they can go back and look through it, post by post. Much more of a PITA to have people include a couple of hundred lines of text - or more - and then reply with a couple of words...... As to the actual topic of the post, yes, the analyser might be picking up a strong local transmission that is confusing it - having said that, at my current QTH, I am pretty close to a number of MW broadcast sites with high TX levels and I have not experienced any of the problems or issues as outlined by Andy. me "Ian Jackson" wrote in message ... Andy, you've gone back to top posting, and this makes it very difficult to follow the discussion. In newsgroups (unlike emails), you should really post at the bottom. This is the established convention. Anyway, it's interesting what you have found out with the dipole configuration. Presumably, you still have the coax braid and one side of 300 ohm feeder earthed. If so, I would not have expected there to be quite such a dramatic change of resonance. However, if your earth rods are totally ineffective (or you have disconnected the earth), you might expect things to change a lot when you add 'the other half of the dipole'. If you actually have room to put up an appx 60 foot + 60 foot dipole, why not consider a G5RV (which, I believe, you have already tried) or a W3DZZ trap dipole? This would get rid of your earthing problems. -- Ian |
PALSTAR AT1KP Meter 1200 Watt Antenna Tuner
On Jun 26, 12:09*am, Walt Davidson wrote:
On Thu, 26 Jun 2008 00:00:39 +1000, "wazzzzup" wrote: [drivel snipped] Kill-filed for top-posting. 73 de G3NYY -- Walt Davidson * * * * * * * * * * * * * * * Email: g3nyy @despammed.com Kill-filed for being a ******. |
| All times are GMT +1. The time now is 10:57 AM. |
Powered by vBulletin® Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
RadioBanter.com