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Long wire at 6m?
Can I use a long wire at 6m with a random wire antenna tuner?
The wire is about 1/4 mile long, and off the ground about 6 foot, (old electrified fence line on top of a fence) Any Idea what the pattern would be? or if it would work? Thanks |
Try loading it thru a tuner and let us know !!
Go for it John! Mitch KD4HTW "John Smith" wrote in message ... Can I use a long wire at 6m with a random wire antenna tuner? The wire is about 1/4 mile long, and off the ground about 6 foot, (old electrified fence line on top of a fence) Any Idea what the pattern would be? or if it would work? Thanks |
On Sat, 27 Mar 2004 13:28:33 -0600, "John Smith"
wrote: Can I use a long wire at 6m with a random wire antenna tuner? The wire is about 1/4 mile long, and off the ground about 6 foot, (old electrified fence line on top of a fence) Any Idea what the pattern would be? or if it would work? Thanks Hi John, Well at least we don't need to preface this with it wouldn't be worth the effort (it's already strung). Basically you will see about 15dB gain along its axis, maybe 2dB broadside and every value in between (including negative values) as you box the compass. When modeled, it gives the picture of a hedge-hog. There are sooooo many lobes you are bound to see at least dipole performance in any direction. 73's Richard Clark, KB7QHC |
Nope, it will be much much less than dipole in almost every direction
except the direction of the wire. There is only so much energy to go around, and most of it is going in the forward or forward/backward directions, depending on termination of the wire. "You cannu break the laws of physics, captain!" - Only a half wave dipole will act like a half wave dipole. tom K0TAR Richard Clark wrote: On Sat, 27 Mar 2004 13:28:33 -0600, "John Smith" wrote: snip Hi John, snip There are sooooo many lobes you are bound to see at least dipole performance in any direction. 73's Richard Clark, KB7QHC |
On 27-Mar-2004, "John Smith" wrote: Can I use a long wire at 6m with a random wire antenna tuner? The wire is about 1/4 mile long, and off the ground about 6 foot, (old electrified fence line on top of a fence) Any Idea what the pattern would be? or if it would work? Thanks Take it with a grain of salt. Quick and dirty evaluation with EZNEC (Real MININEC ground, #10 Aluminum wire) shows 9.65 dBi at 10 deg elevation, vertical beamwidth of 2.7 deg., and horizontal beamwidth of 11 deg. in the direction of the unfed end. I had to reduce the length to 1050 ft. to keep the number of segments below EZNEC's limit of 500. I suspect that the gain and beamwidth would not be much different at 1320 feet. I just played around with the length trying to find a resonant point. Seems that as the length is reduced, the resistive part of the feedpoint impedance changes from around 200 ohms to around 800 ohms while the reactive part is always negative. I placed the source at the bottom of a vertical wire from ground to the horizontal wire. Other feedpoints might differ. Anyway, it looks like a fairly high impedance feed. So if you want a strong signal in the direction of the fence at 10 deg. elevation, it might be a useful antenna. Other directions will suffer. Ken Fowler, KO6NO |
On Sat, 27 Mar 2004 21:41:20 -0600, Tom Ring
wrote: Nope, it will be much much less than dipole in almost every direction except the direction of the wire. There is only so much energy to go around, and most of it is going in the forward or forward/backward directions, depending on termination of the wire. "You cannu break the laws of physics, captain!" - Only a half wave dipole will act like a half wave dipole. tom Hello Major Tom, Count down, systems on. You haven't modeled have you? 73's Richard Clark, KB7QHC |
The heck with 6 meters, you've got a near-ideal Beverage! Go for 160M!
73 Joe D N2LJD "John Smith" wrote in message ... Can I use a long wire at 6m with a random wire antenna tuner? The wire is about 1/4 mile long, and off the ground about 6 foot, (old electrified fence line on top of a fence) Any Idea what the pattern would be? or if it would work? Thanks |
Enough so I don't have to model the obvious. I alpha tested 3 different
modeling programs for the author in the early 90's, currently own 5 if I remember correctly, have modeled hundreds of yagis, built dozens, and tons of other, non-yagi radiating structures. And designed and built the highest gain 432 antenna ever tested at Central States VHF Conference. :) If most of the energy is going off the end(s), there can't be much left to go off the sides, therefore it can't perform like a dipole off the sides. Those little spikes are very misleading, and very narrow. Apply an averaging function 2 or 3 degrees wide on the spikes and the nulls, and you'll see a much truer picture. The physics doesn't lie - antenna patterns are a have to add up to 100% of the input power (ignoring losses). If, picking nice round numbers, 90% is in 5 degrees off the end, then only 10% is available for th. tom K0TAR Richard Clark wrote: On Sat, 27 Mar 2004 21:41:20 -0600, Tom Ring wrote: Nope, it will be much much less than dipole in almost every direction except the direction of the wire. There is only so much energy to go around, and most of it is going in the forward or forward/backward directions, depending on termination of the wire. "You cannu break the laws of physics, captain!" - Only a half wave dipole will act like a half wave dipole. tom Hello Major Tom, Count down, systems on. You haven't modeled have you? 73's Richard Clark, KB7QHC |
On Sun, 28 Mar 2004 07:38:59 -0600, Tom Ring
wrote: If most of the energy is going off the end(s), there can't be much left to go off the sides, therefore it can't perform like a dipole off the sides. Those little spikes are very misleading, and very narrow. Apply an averaging function 2 or 3 degrees wide on the spikes and the nulls, and you'll see a much truer picture. The program defaulted to 5 degrees which still presented so many lobes as to be a pin cushion. The net effect is that aside from axial gain, off side is still pretty much dipole average. No one really expects those sharp lobes to actually represent reality except if you were working EME with an apeture that couldn't see ground. Such deep nulls of only a couple degrees wide only exist in line of sight. There's a world of difference between modeling antenna characteristics and propagation reality. The physics doesn't lie - antenna patterns are a have to add up to 100% of the input power (ignoring losses). If, picking nice round numbers, 90% is in 5 degrees off the end, then only 10% is available for th. 90% for 10% coverage does not absorb all the gain available; the multitude of sharp lobes in excess of 2dBi is abundant proof of that. 73's Richard Clark, KB7QHC |
On Sun, 28 Mar 2004 07:38:59 -0600, Tom Ring
wrote: Enough so I don't have to model the obvious. I alpha tested 3 different modeling programs for the author in the early 90's, currently own 5 if I remember correctly, have modeled hundreds of yagis, built dozens, and tons of other, non-yagi radiating structures. And designed and built the highest gain 432 antenna ever tested at Central States VHF Conference. :) If most of the energy is going off the end(s), there can't be much left to go off the sides, therefore it can't perform like a dipole off the sides. Suppose you modeled it as a longish dipole? One leg is a quarter wave at six meters, the other leg is an odd number of 6-meter quarter waves, stretching out a quarter mile? Bob k5qwg Those little spikes are very misleading, and very narrow. Apply an averaging function 2 or 3 degrees wide on the spikes and the nulls, and you'll see a much truer picture. The physics doesn't lie - antenna patterns are a have to add up to 100% of the input power (ignoring losses). If, picking nice round numbers, 90% is in 5 degrees off the end, then only 10% is available for th. tom K0TAR Richard Clark wrote: On Sat, 27 Mar 2004 21:41:20 -0600, Tom Ring wrote: Nope, it will be much much less than dipole in almost every direction except the direction of the wire. There is only so much energy to go around, and most of it is going in the forward or forward/backward directions, depending on termination of the wire. "You cannu break the laws of physics, captain!" - Only a half wave dipole will act like a half wave dipole. tom Hello Major Tom, Count down, systems on. You haven't modeled have you? 73's Richard Clark, KB7QHC |
"John Smith" wrote in message ...
Can I use a long wire at 6m with a random wire antenna tuner? The wire is about 1/4 mile long, and off the ground about 6 foot, (old electrified fence line on top of a fence) Any Idea what the pattern would be? or if it would work? Thanks Sure, it would *work*, but I would rather use something else. The size of a yagi on 6m is not too big. "appx 9 ft or so elements on average". I built one from all hard drawn copper tubing, and welded it all together as one piece. "plumbers delight". I have a torch... Probably cost me $20 in copper. It will probably smoke any random or long wire. One reason is my 6m radio is a icom ic-706mk2g. It's prone to HF images on 6m, if you use an antenna that provides a large HF signal level in comparison to the 6m level. Trash city on any of my HF antennas. But you get on the yagi, with it's fairly good attenuation of HF signals, and it cleans it right up. Also, the beam is rotatable. The wire would be stuck in 2 directions. Or one of two if you terminated the antenna at an end. You can try it, but plan on a beam if you really want decent performance. A 6m beam is small enough to mount with TV hardware and rotors. They are real light if you use aluminum. BTW, I'd skip the simple dipoles and verticals also...Wimpy antennas on 6m compared to a yagi or quad....:( But also depends on the mode...I work mainly SSB in the low end. A vertical or dipole will be trounced by my simple 3 el yagi. Both transmit and receive. I can hear stuff on the beam that is not there on a vertical or dipole. MK |
"John Smith" wrote in message ...
Can I use a long wire at 6m with a random wire antenna tuner? The wire is about 1/4 mile long, and off the ground about 6 foot, (old electrified fence line on top of a fence) Any Idea what the pattern would be? or if it would work? Thanks Sure, it would *work*, but I would rather use something else. The size of a yagi on 6m is not too big. "appx 9 ft or so elements on average". I built one from all hard drawn copper tubing, and welded it all together as one piece. "plumbers delight". I have a torch... Probably cost me $20 in copper. It will probably smoke any random or long wire. One reason is my 6m radio is a icom ic-706mk2g. It's prone to HF images on 6m, if you use an antenna that provides a large HF signal level in comparison to the 6m level. Trash city on any of my HF antennas. But you get on the yagi, with it's fairly good attenuation of HF signals, and it cleans it right up. Also, the beam is rotatable. The wire would be stuck in 2 directions. Or one of two if you terminated the antenna at an end. You can try it, but plan on a beam if you really want decent performance. A 6m beam is small enough to mount with TV hardware and rotors. They are real light if you use aluminum. BTW, I'd skip the simple dipoles and verticals also...Wimpy antennas on 6m compared to a yagi or quad....:( But also depends on the mode...I work mainly SSB in the low end. A vertical or dipole will be trounced by my simple 3 el yagi. Both transmit and receive. I can hear stuff on the beam that is not there on a vertical or dipole. MK |
The condition of the insulators at 6 meters may be a factor.
73 Hank WD5JFR "John Smith" wrote in message ... Can I use a long wire at 6m with a random wire antenna tuner? The wire is about 1/4 mile long, and off the ground about 6 foot, (old electrified fence line on top of a fence) Any Idea what the pattern would be? or if it would work? Thanks |
I seem to remember a few years back, a guy with a similar antenna used it as
a high gain end-fire on 2m EME. The moon didn't stay in the main lobe very long, but when it was there he had a pretty good EME station! George, K6GW "John Smith" wrote in message ... Can I use a long wire at 6m with a random wire antenna tuner? The wire is about 1/4 mile long, and off the ground about 6 foot, (old electrified fence line on top of a fence) Any Idea what the pattern would be? or if it would work? Thanks |
"George" wrote in message ink.net... I seem to remember a few years back, a guy with a similar antenna used it as a high gain end-fire on 2m EME. The moon didn't stay in the main lobe very long, but when it was there he had a pretty good EME station! George, K6GW I'd be very surprised if this really worked- the warm earth noise p/u from a long wire would be horrendous, ruining the G/T. Perhaps you were thinking of a terminated rhomboid? Dale W4OP |
Well I had some good typo and editing errors there. But I think the
message was still evident. Rule #1 - don't edit a message more than once. tom Tom Ring wrote: Enough so I don't have to model the obvious. I alpha tested 3 different modeling programs for the author in the early 90's, currently own 5 if I remember correctly, have modeled hundreds of yagis, built dozens, and tons of other, non-yagi radiating structures. And designed and built the highest gain 432 antenna ever tested at Central States VHF Conference. :) If most of the energy is going off the end(s), there can't be much left to go off the sides, therefore it can't perform like a dipole off the sides. Those little spikes are very misleading, and very narrow. Apply an averaging function 2 or 3 degrees wide on the spikes and the nulls, and you'll see a much truer picture. The physics doesn't lie - antenna patterns are a have to add up to 100% of the input power (ignoring losses). If, picking nice round numbers, 90% is in 5 degrees off the end, then only 10% is available for th. tom K0TAR Richard Clark wrote: On Sat, 27 Mar 2004 21:41:20 -0600, Tom Ring wrote: Nope, it will be much much less than dipole in almost every direction except the direction of the wire. There is only so much energy to go around, and most of it is going in the forward or forward/backward directions, depending on termination of the wire. "You cannu break the laws of physics, captain!" - Only a half wave dipole will act like a half wave dipole. tom Hello Major Tom, Count down, systems on. You haven't modeled have you? 73's Richard Clark, KB7QHC |
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