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Installing a Ladder Line to the house
I've read some Q&A about ladder line and I didn't see exactly my
question. I want to run 450 ohm ladder line into the house. my tuner has a built-in balun for a ladder line so I think I can just run the ladder line all the way to the tuner. How do I physically attach the ladder line to the house? All I can think of is to nail it right through the spacers onto the side of the house. But I don't know if the nails will interfere with transmission at all. A second that comes to mind when considering this setup: if I run the ladder line all the way to the tuner, how do I ground it? Thanks, kb1odg |
Installing a Ladder Line to the house
James barrett wrote:
How do I physically attach the ladder line to the house? I use electric fence insulators. A second that comes to mind when considering this setup: if I run the ladder line all the way to the tuner, how do I ground it? No RF ground required. -- 73, Cecil http://www.w5dxp.com |
Installing a Ladder Line to the house
Some have tried using 1-ft lengths (or so) of PVC at the corners of the
house. Cut a slot in one end of the PVC, put a nail-hole or two near the other end - secure the line in the slot of the pvc using nylon ty-raps. "James barrett" wrote in message ... I've read some Q&A about ladder line and I didn't see exactly my question. I want to run 450 ohm ladder line into the house. my tuner has a built-in balun for a ladder line so I think I can just run the ladder line all the way to the tuner. How do I physically attach the ladder line to the house? All I can think of is to nail it right through the spacers onto the side of the house. But I don't know if the nails will interfere with transmission at all. A second that comes to mind when considering this setup: if I run the ladder line all the way to the tuner, how do I ground it? Thanks, kb1odg |
Installing a Ladder Line to the house
On Tue, 6 Jan 2009 14:00:43 -0800 (PST), James barrett
wrote: How do I physically attach the ladder line to the house? http://www.fishock.com/energizedFencing/insulators.htm http://www.fencesafe.com/insulators.html http://www.redhillgeneralstore.com/efwoodins.htm etc. Search for "electric fence insulators". If you want to be really creative, you could just build a spacer from ABS or PVC pipe, using a flange mount at one end, and a hole drilled in the pipe to support the wire. Maybe a plastic "T" at the end to support both wires on one insulator. Be creative. No ground required for a balanced system. However, methinks it's a good idea to ground the radio and the antenna tuner case. -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
Installing a Ladder Line to the house
James barrett wrote:
I've read some Q&A about ladder line and I didn't see exactly my question. I want to run 450 ohm ladder line into the house. my tuner has a built-in balun for a ladder line so I think I can just run the ladder line all the way to the tuner. How do I physically attach the ladder line to the house? All I can think of is to nail it right through the spacers onto the side of the house. But I don't know if the nails will interfere with transmission at all. A second that comes to mind when considering this setup: if I run the ladder line all the way to the tuner, how do I ground it? Thanks, kb1odg Use coaxial cable to get through the wall, then a BalUn outside to transition to the balanced transmission line. |
Installing a Ladder Line to the house
"Dave" wrote in message ... James barrett wrote: I've read some Q&A about ladder line and I didn't see exactly my question. I want to run 450 ohm ladder line into the house. my tuner has a built-in balun for a ladder line so I think I can just run the ladder line all the way to the tuner. How do I physically attach the ladder line to the house? All I can think of is to nail it right through the spacers onto the side of the house. But I don't know if the nails will interfere with transmission at all. A second that comes to mind when considering this setup: if I run the ladder line all the way to the tuner, how do I ground it? Thanks, kb1odg Use coaxial cable to get through the wall, then a BalUn outside to transition to the balanced transmission line. -------- I'm running a Van Gordon All Bander dipole. It utilizes 450 twinlead from the dipole, thru the barrier into the house and connects to the 4:1 balun in my MFJ-989C manual roller inductor tuner. Instead of drilling a hole through the cinder blocks of my basement wall (finished), I made up a barrier insert from a piece of 2x4" lumber to fit under the lip of my window. I drilled two holes through the 2x4" lumber spaced at the same distance as the conductors in the twinlead. I then used a router bit to connect the dots. A very thin router bit. In fact, I think it was the bit from my cut in any direction saw that I bought several years ago and can't think of the name of it at the moment. They were all the rage on TV. It rotates like a drill bit or router bit. I hope you can follow me. I made the cut in the barrier board for the twinlead tight enough that I haven't even bothered to silicone up the gap, it is that tight. I haven't had any problems with it at all. No fires, no arcing, no scorching the wood. I think it would take a lot more power to do that than my 1kw Ameritron AL-80A can produce. Is it a PITA (Pain In The Ass)? Yes. But it gets me any band that I want, including six meters (in fine fashion too). If you go the coax route, you'll end up with a G5RV that won't take more than 200 watts without frying the twinlead, or you'll end up with a trapped doublet that only gives you a few kilohertz operating bandwidth on most bands. Chances are that some bands will be unusable unless you have a good tuner (no, not an autotuner - they don't have enough "swing"). Running a piece of coax into twinlead with an antenna with high SWR can generate high enough voltages to punch a hole through the coax' dielectric. After that hole has been made, the voltage needed to jump that arc from then on will be much lower, meaning that your signal will sound crappy and you may have problems with your rig. I put up with the 450 ohm twinlead all of the way into the house because it provides me with the most bands in the smallest space. It will also handle a kilowatt without protest. Oh, I haven't seen a 4:1 balun that is worth what it costs to ship to your door that sells for less than $139. I've gone through three brands lately. Brands that were supposed to be (and used to be) top shelf. Makes me wish I had held on to the good one that I bought years ago. That'll learn me. Good luck. Ed, N2ECW |
Installing a Ladder Line to the house
James,
Since it's been a while since ladder line has been in common use, there aren't many 'standard' ways of doing things in common usage anymore. So, as long as you keep a few things in mind, your imagination will supply you with any number of 'ways' to do things. Sharp bends, being close to metal things, and 'deforming' the feed line's shape too much are things to avoid. After that, it's more or less whatever you can think of, sort of. Lot's of 'wiggle' room in that, your millage may vary, etc. Good luck. - 'Doc |
Installing a Ladder Line to the house
In message , Dave
writes James barrett wrote: I've read some Q&A about ladder line and I didn't see exactly my question. I want to run 450 ohm ladder line into the house. my tuner has a built-in balun for a ladder line so I think I can just run the ladder line all the way to the tuner. How do I physically attach the ladder line to the house? All I can think of is to nail it right through the spacers onto the side of the house. But I don't know if the nails will interfere with transmission at all. A second that comes to mind when considering this setup: if I run the ladder line all the way to the tuner, how do I ground it? Thanks, kb1odg Use coaxial cable to get through the wall, then a BalUn outside to transition to the balanced transmission line. Baluns don't like 'funny' impedances. Better to use 75 ohm twin through the wall. If you don't have any lying around, maybe a bit of domestic twin power cable/cord could be pressed into service. -- Ian |
Installing a Ladder Line to the house
On Wed, 07 Jan 2009 13:22:19 +0000, Dave wrote:
James barrett wrote: I've read some Q&A about ladder line and I didn't see exactly my question. I want to run 450 ohm ladder line into the house. my tuner has a built-in balun for a ladder line so I think I can just run the ladder line all the way to the tuner. How do I physically attach the ladder line to the house? All I can think of is to nail it right through the spacers onto the side of the house. But I don't know if the nails will interfere with transmission at all. A second that comes to mind when considering this setup: if I run the ladder line all the way to the tuner, how do I ground it? Thanks, kb1odg Use coaxial cable to get through the wall, then a BalUn outside to transition to the balanced transmission line. I've had good luck bringing 450-ohm line through the window using MFJ's 4602 window feed through board. It has ceramic feed through insulators for the balanced line, more feedthrough's for a random wire, three coax lines and a ground wire. Even includes weather stripping and a burgler bar. Bob k5qwg |
Installing a Ladder Line to the house
On Tue, 6 Jan 2009 14:00:43 -0800 (PST), James barrett
wrote: I've read some Q&A about ladder line and I didn't see exactly my question. I want to run 450 ohm ladder line into the house. my tuner has a built-in balun for a ladder line so I think I can just run the ladder line all the way to the tuner. How do I physically attach the ladder line to the house? All I can think of is to nail it right through the spacers onto the side of the house. But I don't know if the nails will interfere with transmission at all. A second that comes to mind when considering this setup: if I run the ladder line all the way to the tuner, how do I ground it? Thanks, kb1odg James, You don't mention whether your antenna is resonant or not. Nor do you mention where your feed line enters the house. I use 600 ohm ladder line to feed my 220 foot dipole from Antenna tuner to Ten Tec L Tuner located near a basement window. There are a number of problems that I have solved since my antenna is between two trees about 300 feet apart. I support it using Dacron rope at both ends. One end is fixed. the other goes through a pulley to a 40 lb sealed box of cat litter. This helps to prevent the destruction of the antenna by wind- whipped trees. The antenna may be overkill: #10 copperweld and W7FY feed line. However, 40 lbs does not keep the antenna from flexing +-6-8 feet.. You need spring action of some sort to prevent the feed line from being ripped loose from the house or point to which it is first attached. I use plain string/twine to make an attachment from house to a spreader in the line. The string is adjusted so that the line is straight to the point where the string is attached to the house entry point and so that the line above where the string is attached is "draped" providing the ability for the antenna to go up or down 6-8 feet from its normal position. Under NE ice conditions it does drop that much and in high winds it can go up the 8 feet. I bring the line into the house through a basement window in which a Plexiglas insert has feed through insulators for external ground and the feed line. The string limits tension and flex on those insulators. Feed line from the insulators goes to the tuner when operating and to ground when not. There are feed line lightning arrestors that use spark plugs as grounding elements. I have not used these as I am worried that standing wave voltage nodes that I have on the line might trigger the spark plugs when running high power since I use the antenna from 160-10 on CW and SSB. If you have questions about my arrangement, I'll be happy to try to answer them. Ed, N5EI |
Installing a Ladder Line to the house
Ed Cregger wrote:
Instead of drilling a hole through the cinder blocks of my basement wall (finished), I made up a barrier insert from a piece of 2x4" lumber to fit under the lip of my window. MFJ offers six window-mounted feed through panels for such. Their numbers are 4600-4605. MFJ-4600 has four balanced and two coaxial feed-throughs. Oh, I haven't seen a 4:1 balun that is worth what it costs to ship to your door that sells for less than $139. I've gone through three brands lately. If one doesn't know what magnitude of impedance is being encountered by the balun, the best balun solution is a husky 1:1 current (choke) balun, not a 4:1 voltage balun which is designed to deal with 200 ohms, not 2000+j2000 ohms. -- 73, Cecil http://www.w5dxp.com |
Installing a Ladder Line to the house
"James barrett" wrote in message ... I've read some Q&A about ladder line and I didn't see exactly my question. I want to run 450 ohm ladder line into the house. my tuner has a built-in balun for a ladder line so I think I can just run the ladder line all the way to the tuner. How do I physically attach the ladder line to the house? All I can think of is to nail it right through the spacers onto the side of the house. But I don't know if the nails will interfere with transmission at all. A second that comes to mind when considering this setup: if I run the ladder line all the way to the tuner, how do I ground it? Thanks, kb1odg I have thought of running ladder line through the wood above the basement wall, and accross the joists above a suspended ceiling. My main concerns a the very high field intesity on the plane of the transmission line, and the high voltage present when using a short dipole. For example with 100 W in; a 100 ft dipole, 55 ft of transmission line on 1.9 MHz shows: 400 V/m (peak) only 6" from each side of the ladder line, and a peak input voltage of 2.4 kV. While the above is an extreme example I think some analysis needs to be done before attempting such an instalation. With all the satellite coax, and house wiring in the ceiling I wondered how much TVI I would get. On 40 m I estimate about 8 V/m (peak) from the antenna (1Kw out) at the TV. It is enough to get into the remote control circuitry, and turn on the TV menu blocking out the picture. 73, Frank |
Installing a Ladder Line to the house
Frank,
The 'simple' answer? Keep away from 'stuff' it may interfere with. As for the worst case thing with high voltage? Change your antenna arrangement. How about hanging that ladder line from the suspended ceiling? Out of the typical 'foot traffic zones'? Anyone asks, tell'em it's an RF railroad line to your antenna. Sound crazy? so what, 'they' think we're crazy anyway... - 'Doc |
Installing a Ladder Line to the house
Bob Miller wrote:
I've had good luck bringing 450-ohm line through the window using MFJ's 4602 window feed through board. It has ceramic feed through insulators for the balanced line, more feedthrough's for a random wire, three coax lines and a ground wire. Even includes weather stripping and a burgler bar. Bob k5qwg That's through a window, not through a wall. I use the MFJ myself. If I did want to use non-resonant antennas I would locate a tuner at the antenna feedpoint, not at the generator (transmitter). |
Installing a Ladder Line to the house
"Dave" wrote in message m... Bob Miller wrote: I've had good luck bringing 450-ohm line through the window using MFJ's 4602 window feed through board. It has ceramic feed through insulators for the balanced line, more feedthrough's for a random wire, three coax lines and a ground wire. Even includes weather stripping and a burgler bar. Bob k5qwg That's through a window, not through a wall. I use the MFJ myself. If I did want to use non-resonant antennas I would locate a tuner at the antenna feedpoint, not at the generator (transmitter). Then you would cheat yourself of a fair amount of propagation and some of the lower and higher frequencies available with such a set up. You're not going to keep RF out of the shack, regardless of which system you use. You might be able to keep some of the hot spots outside, but often times they are close enough to the station that it is really a waste of time. This fascination with resonance is a leftover from CB thinking. How many warships utilize resonant antennas? Yet they communicate the world over. The aversion to transmatches is a ham cultural trait that has no basis in reality, just as the CB'ers are hooked on resonant 50 ohm antennas. It's a characteristic of the culture(s) of both types of operators, with no basis in practical operating engineering. Ed, N2ECW |
Installing a Ladder Line to the house
Ed Cregger wrote:
You're not going to keep RF out of the shack, regardless of which system you use. My no-tuner HF antenna system at: http://www.w5dxp.com/notuner.htm has negligible measured RF-in-the-shack even though the antenna is a non-resonant length on most HF bands. -- 73, Cecil http://www.w5dxp.com |
Installing a Ladder Line to the house
On Thu, 8 Jan 2009 08:50:33 -0500, "Ed Cregger"
wrote: "Dave" wrote in message om... Bob Miller wrote: I've had good luck bringing 450-ohm line through the window using MFJ's 4602 window feed through board. It has ceramic feed through insulators for the balanced line, more feedthrough's for a random wire, three coax lines and a ground wire. Even includes weather stripping and a burgler bar. Bob k5qwg That's through a window, not through a wall. I use the MFJ myself. If I did want to use non-resonant antennas I would locate a tuner at the antenna feedpoint, not at the generator (transmitter). Then you would cheat yourself of a fair amount of propagation and some of the lower and higher frequencies available with such a set up. You're not going to keep RF out of the shack, regardless of which system you use. FYI my 80 meter dipole with ladder line all way to the indoor tuner does not emit RFI in the shack that I can notice, even when put into all band use. bob k5qwg You might be able to keep some of the hot spots outside, but often times they are close enough to the station that it is really a waste of time. This fascination with resonance is a leftover from CB thinking. How many warships utilize resonant antennas? Yet they communicate the world over. The aversion to transmatches is a ham cultural trait that has no basis in reality, just as the CB'ers are hooked on resonant 50 ohm antennas. It's a characteristic of the culture(s) of both types of operators, with no basis in practical operating engineering. Ed, N2ECW |
Installing a Ladder Line to the house
On Jan 8, 7:50*am, "Ed Cregger" wrote:
The aversion to transmatches is a ham cultural trait that has no basis in reality, just as the CB'ers are hooked on resonant 50 ohm antennas. It's a characteristic of the culture(s) of both types of operators, with no basis in practical operating engineering. Ed, N2ECW I wouldn't say that. As an example, I've done tests showing that no matter how careful I am with the tuner, it's settings, decent open wire feeder, etc, I could never quite equal the performance of a coax fed dipole when feeding the same antenna using the tuner and ladder line. Quite close granted, and to many people a non issue, but there *was* a difference. Of course, the coax fed dipoles I use would generally be considered a single band antenna. But that's no problem here. But if I have my way, I avoid tuners if possible. I'm trading the ability of fairly efficient multi band use, for the slightly more efficient coax fed single band antenna. I want to radiate every drop of RF I can. Also the settings of the tuner are fairly critical for the most efficient use. I have a 989c also, and I have done extensive testing with it using various settings vs efficiency. I found with the usual T network tuner such as the 989c, you might be able to tune a load with 25 or more settings. But only the setting using the least inductance will be fairly low loss. All of the settings that use more inductance than required show more tuner loss. Up to about 20% of your power is lost in a worst case scenario. So that is another issue. Small, being as one can make sure to use the least inductance, but it's just another thing to fuss with when changing bands. Myself, I prefer to use multiple element antenna elements to provide multi band capability. The system efficiency is very high, and I don't have to do anything when I change bands. It's not using a resonant antenna that makes it very efficient. It's the ability to use the 50 ohm radio to a low loss 50 ohm feed line, straight to the appx 50 ohm antenna without any semi lossy mickey mouse stuff in between. :/ Now if I were required to use only one wire for all bands, I wouldn't have any problems using ladder line and the tuner to feed a single dipole. It will work quite well, and being I don't have the coax fed to compare to, no one will notice the difference. But I bet they would notice a slight difference if I did have both to compare to. The reason I know this is because I have tried it. "75m" I could see the difference on receive, no real need to compare on air reports. But I did anyway, and as expected, they saw about the same difference between the two systems. When comparing the ladder line and tuner system vs the coax system, if I had a signal that was 40 db over S9 on the tuner system, it would bump up to about 45 db over S9 with the coax feed. For me to see that large a difference on receive, the tuner loss can not be considered to be just an illusion or not based in reality. I have no problems with anyone else using one, but I think it's a stretch to say that anyone that prefers to avoid one is trying to emulate a CB'er.. :/ |
Installing a Ladder Line to the house
The 'simple' answer? Keep away from 'stuff' it may interfere with.
As for the worst case thing with high voltage? Change your antenna arrangement. How about hanging that ladder line from the suspended ceiling? Out of the typical 'foot traffic zones'? Anyone asks, tell'em it's an RF railroad line to your antenna. Sound crazy? so what, 'they' think we're crazy anyway... - 'Doc Most of the wiring in the ceiling is what I put there. I just wanted to demonstrate some of the problems associated with such an instalation. Passing high voltage lines through wood -- even with a ceramic sleeve -- is what really bothered me. The fact is I have room for a 200 ft dipole, but on 160 m there are still high voltages on the transmission line. I have pretty much made up my mind to build a remote tuner, but the parts are very expensive. Frank |
Installing a Ladder Line to the house
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Installing a Ladder Line to the house
On Jan 8, 11:31*am, Roy Lewallen wrote:
But amateurs tend to use multiband antennas without any thought at all to radiation pattern. When the frequency gets considerably higher than a dipole's resonant frequency, the pattern changes. So there's a good chance that the pattern will have nulls in at least some directions where you might want to communicate. In those cases, the difference between a half wavelength dipole and much longer dipole can be striking. That's another reason why I prefer the separate elements for multi band use, vs the single wire. I generally prefer the normal dipole pattern on most of the bands I use. It's relatively easy to measure tuner efficiency when it's working into a nice resistive load. But I'm curious about how you measured the power the tuner was delivering to a more realistic non-resonant load impedance. The only way I can think of to do it with any semblance of accuracy is to connect two identical tuners back-to-back and measure the power out of the combination. Is that how you did it? If not, how? It's been so long since I did that, I forgot exactly how I came to that conclusion. But I think I was using my resonant coax fed dipole as the load, and pretty sure I had dual watt meters. One before the tuner, and another after the tuner. The tuner has an antenna switch to bypass the tuner. I believe what I did was measure the power on both meters with the tuner bypassed, and then tried using the tuner as a "line flattener", more than an actual tuner, being the system was already resonant. I tried various settings of the tuner, trying quite a few variations in inductance vs cap settings to see if I could notice much loss with the tuner inline. The radio was my old IC 730 and I used full power for the tests. The meter after the radio was used to verify the appx power from the radio, and it stayed fairly constant in all the tests. The meter after the tuner was used to check the power at that point in the line. In all cases, the tuner would indicate a "flat" match with all the various settings, so any variation in the output of the radio should have been small, and the meter after it verified this. But the meter on the other side of the tuner could vary anywhere from about 20% less, to almost unnoticeable difference, depending on the inductance setting of the tuner. This test didn't tell me much about the losses using non resonant loads fed with ladder line, but I suspect that the loss would still be greatly defendant on the inductance setting. I would think the loss would greatly vary just depending on the load at the moment. Could be high, as if feeding a half size dipole with a T network tuner, or pretty low with other longer wire lengths. I didn't try to worry about the exact loss in numbers, but I could see the problem cropping up fairly easy if one were lazy about using the least inductance setting, or if using a tuner with a tapped coil that was not the optimum setting. My tuner uses a roller inductor, which lets me tune to exactly the best spot on the coil, but some tuners tap and switch the coil position. With some of those, loss could be more noticeable if it's compromise setting was way off from optimum. Another thing I noticed that was it didn't take a whole lot of extra inductance for the losses to begin to show. Basically, I found there is only one tuner setting that will give you fairly low loss in such a case. The one using the least inductance to get a usable match for the radio. All the other settings would show quite a bit more loss, and it didn't take too much more inductance to start seeing 10-15-20 % decreases in output from the tuner. And all these settings show a perfect match to the radio. But if using the least inductance in such a case, the meter reading was so close as to almost be the same vs bypassing the tuner. So you can use a tuner and have low loss if you are careful about tuning. Sure, even 20% won't make much of a difference on the other end, but I'd prefer not to lose it none the less. I'm usually on the noisy lower bands, and I rarely run an amp anymore. That's why I insist on every drop. In the summer, I usually need every drop.. :/ I also prefer coax anyway just due to the convenience. But if I run ladder line, I run ladder line the whole way. I don't like running coax to ladder line. I either use one or the other. |
Installing a Ladder Line to the house
On Jan 8, 12:48*pm, Cecil Moore wrote:
wrote: When comparing the ladder line and tuner system vs the coax system, if I had a signal that was 40 db over S9 on the tuner system, it would bump up to about 45 db over S9 with the coax feed. Balanced tuner or balun plus unbalanced tuner? If balun, what kind? Was the balun seeing its designed-for impedance? What do you think would be the A/B results for a resonant coax-fed dipole vs my notuner dipole? Probably about the same. In theory you would have slightly less loss than the coax, but at the lower frequencies even the coax has very low loss. So being the losses for both are very low, I don't think you would be able to see much difference. Or that's my gut hunch anyway.. Yours would probably be better than the coax if the run was several hundred feet. At that distance, the slight difference might begin to show up more. Also if used at fairly high frequencies, you might have an advantage. Depends on how good the coax is how much it would be. |
Installing a Ladder Line to the house
Ed Cregger wrote:
"Dave" wrote in message If I did want to use non-resonant antennas I would locate a tuner at the antenna feedpoint, not at the generator (transmitter). Then you would cheat yourself of a fair amount of propagation and some of the lower and higher frequencies available with such a set up. You're not going to keep RF out of the shack, regardless of which system you use. You might be able to keep some of the hot spots outside, but often times they are close enough to the station that it is really a waste of time. This fascination with resonance is a leftover from CB thinking. How many warships utilize resonant antennas? Yet they communicate the world over. The aversion to transmatches is a ham cultural trait that has no basis in reality, just as the CB'ers are hooked on resonant 50 ohm antennas. It's a characteristic of the culture(s) of both types of operators, with no basis in practical operating engineering. Ed, N2ECW You don't read very well. And you seem a tad hostile. I stated no "aversion" whatsoever to what are called "non-resonant" antennas. I said that I'd locate the tuner at the antenna feedpoint. A transmatch between the radio and the transmission line does little to make the antenna work better. CB thinking? You really have issues. |
Installing a Ladder Line to the house
Dave wrote:
A transmatch between the radio and the transmission line does little to make the antenna work better. That statement is true for a very lossy system but not necessarily true for low-loss real-world systems. Establishing a conjugate match at the antenna feedpoint makes the antenna work better by allowing maximum available power transfer to the antenna. A remote autotuner at the base of the antenna can accomplish that feat. There seems to be developing the myth that a tuner at the shack cannot accomplish that feat. Although strictly technically true, a low-loss tuner and low-loss transmission line can come close enough to achieving a conjugate match at the antenna that almost all of the available power is transferred to the antenna (if losses are made negligible by good engineering practice). It can be proved mathematically that in a lossless system, a conjugate match is established at the antenna feedpoint by the tuner located back in the shack. A near-conjugate match is established in the case of a low-loss system resulting in near-maximum available power transfer to the antenna. -- 73, Cecil http://www.w5dxp.com |
Installing a Ladder Line to the house
On Jan 9, 8:24*am, Cecil Moore wrote:
There seems to be developing the myth that a tuner at the shack cannot accomplish that feat. Although strictly technically true, a low-loss tuner and low-loss transmission line can come close enough to achieving a conjugate match at the antenna that almost all of the available power is transferred to the antenna (if losses are made negligible by good engineering practice). It can be proved mathematically that in a lossless system, a conjugate match is established at the antenna feedpoint by the tuner located back in the shack. A near-conjugate match is established in the case of a low-loss system resulting in near-maximum available power transfer to the antenna. -- 73, Cecil *http://www.w5dxp.com Judging from my mobile antenna tinkering, I'd have to say that is true. As an example, with a short run of coax that feeds the antenna, you would think that it would be required to place the matching device or tuner at the feed point of the vertical. And strictly speaking, it would be the best place for it. But... I've found that you can have very good results if the tuner is at the radio end of the coax. In actual operation, there seems to be little difference in performance. But the short piece of coax "maybe 10 ft long" is fairly low loss on the lower HF frequencies. So it's not a lossless system, but fairly low loss considering the frequency and short length of the line. But if I run a long coax to the same antenna, I would prefer to keep the tuner at the same place, in front of the short 10 ft piece, and then run my long cable from the radio to the tuner, which is still at the car. I often did this when using the radio at picnic tables, tents, while using the mobile antenna on the car. My most recent installs on the two trucks place the matching device at the antenna. But in my older car I once used, I used the tuner at the radio end. It was convenient, and let me fine tune the match while driving. There seems to be little difference in performance that I can see using the short fairly low loss pieces of coax. Not much difference where I place the tuner. So this tends to back up your theory. |
Installing a Ladder Line to the house
"Dave" wrote in message m... Ed Cregger wrote: "Dave" wrote in message If I did want to use non-resonant antennas I would locate a tuner at the antenna feedpoint, not at the generator (transmitter). Then you would cheat yourself of a fair amount of propagation and some of the lower and higher frequencies available with such a set up. You're not going to keep RF out of the shack, regardless of which system you use. You might be able to keep some of the hot spots outside, but often times they are close enough to the station that it is really a waste of time. This fascination with resonance is a leftover from CB thinking. How many warships utilize resonant antennas? Yet they communicate the world over. The aversion to transmatches is a ham cultural trait that has no basis in reality, just as the CB'ers are hooked on resonant 50 ohm antennas. It's a characteristic of the culture(s) of both types of operators, with no basis in practical operating engineering. Ed, N2ECW You don't read very well. And you seem a tad hostile. I stated no "aversion" whatsoever to what are called "non-resonant" antennas. I said that I'd locate the tuner at the antenna feedpoint. A transmatch between the radio and the transmission line does little to make the antenna work better. CB thinking? You really have issues. ----------- Actually, I read very well. We are talking on a worldwide forum. Folks that take every single comment personally have missed that point of view and usually react negatively, as you. If I wanted to raise hell and berate someone, this would be the last usenet group that I would use. Most folks here are scientifically oriented and would be no fun to irritate. I am interested in two-way radio cultures. I own and use CB radios in addition to my amateur gear. I had my FCC commercial ticket long before encountering CB or ham radio. I was introduced to two-way radio while in the USAF, so my view of the cultures is quite different than many civilian radio cultures. No insult was or is intended. When I say someone is oriented toward radio in a CB fashion, it is not necessarily an insult. Why would I insult myself? I may be a bit hostile, that's true. Anyone in the amount of pain that I am in (and there are certainly millions with worse pain than mine) will be a bit short or curt at times. My apologies. The marketing campaigns for CB gear in the seventies placed emphasis on a 50 ohm match with a resonant antenna. Many CB folks received all of their education in radio via those commercials. Many hams, especially those that came from CB, would probably faint if they knew that commercial broadcast stations often have an "antenna tuner" at the base of their broadcast antennas. After all, tuners are no good, right? That was one of the points that I was trying to make. Kind of a preemptive strike on my part to reduce the number of complaints about folks running a dipole antenna configuration while using twinlead feedline with a transmatch at the station. I was not picking on you, nor was I trying to show you in a bad light. Ed, N2ECW |
Installing a Ladder Line to the house
wrote:
But if I run a long coax to the same antenna, I would prefer to keep the tuner at the same place, in front of the short 10 ft piece, and then run my long cable from the radio to the tuner, which is still at the car. When the SWR is not 1:1 but is of a reasonable value: A short coax run is usually low-loss. A long coax run is usually not low-loss. When the tuner is located at the transmitter, the near-conjugate match at the antenna can only be achieved in a low-loss system. Open-wire HF transmission line systems are usually low-loss systems. -- 73, Cecil http://www.w5dxp.com |
Installing a Ladder Line to the house
"Cecil Moore" wrote If one doesn't know what magnitude of impedance is being encountered by the balun, the best balun solution is a husky 1:1 current (choke) balun, not a 4:1 voltage balun which is designed to deal with 200 ohms, not 2000+j2000 ohms. -- 73, Cecil http://www.w5dxp.com ----------- I used to be good at this stuff, Cecil, but that was long ago. The only balun that has worked with any success so far has been the built-in balun (4:1 allegedly) in my MFJ-989C. That I can get to work. When hooking up other baluns and using the coax output on my tuner, none of the other baluns work worth a hoot with one exception. I have an LDG 1:1 200 watt balun that will tune my Van Gordon All Bander from one end to the other of the HF spectrum, using just the internal tuner of my Yaesu FT-890AT. Go figure. I used to be a fairly sharp cookie at this stuff, but those days are in the past. Got a serious case of "brick brain syndrome", if you know what I mean? To my way of thinking (which is probably incorrect), using the 4:1 balun would broaden the impedances that I could match versus the 1:1 balun. What you are saying is just the opposite. Please elaborate. I will be most grateful. Ed, N2ECW |
Installing a Ladder Line to the house
Ed Cregger wrote:
I have an LDG 1:1 200 watt balun that will tune my Van Gordon All Bander from one end to the other of the HF spectrum, using just the internal tuner of my Yaesu FT-890AT. Go figure. If this is the 80m dipole with 100' of ladder-line, one can look at my notuner all-band-HF antenna to see why 100' is a good fixed length for the ladder-line. 100' is near a current maximum point (loop) on all HF bands. If one varies the length of the ladder-line from 90' to 115', one doesn't even need a tuner and a 1:1 current- balun-choke is ideal. http://www.w5dxp.com/pnts130.gif To my way of thinking (which is probably incorrect), using the 4:1 balun would broaden the impedances that I could match versus the 1:1 balun. What you are saying is just the opposite. Please elaborate. I will be most grateful. A 4:1 balun is a very good transformer over a narrow range. Most are voltage baluns that do not balance currents and therefore do little to discourage common-mode currents. Test a balun looking into 2000+j2000 and see what happens. One of my 4:1 baluns got so hot I couldn't touch the case. The best balun design, IMO, is one where flux in the ferrite is caused only by common-mode current and not by differential-mode current. Here's some useful information: http://www.dxengineering.com/TechArticles.asp?ID={3E5220F7-2D0F-45B5-85F7-3B654F804C4F} -- 73, Cecil http://www.w5dxp.com |
Installing a Ladder Line to the house
Cecil Moore wrote:
http://www.dxengineering.com/TechArticles.asp?ID={3E5220F7-2D0F-45B5-85F7-3B654F804C4F} If anyone has trouble with that URL, you may need to cut and paste the entire URL into your browser. -- 73, Cecil http://www.w5dxp.com |
Installing a Ladder Line to the house
On Jan 11, 8:59*am, Cecil Moore wrote:
Ed Cregger wrote: I have an LDG 1:1 200 watt balun that will tune my Van Gordon All Bander from one end to the other of the HF spectrum, using just the internal tuner of my Yaesu FT-890AT. Go figure. If this is the 80m dipole with 100' of ladder-line, one can look at my notuner all-band-HF antenna to see why 100' is a good fixed length for the ladder-line. 100' is near a current maximum point (loop) on all HF bands. If one varies the length of the ladder-line from 90' to 115', one doesn't even need a tuner and a 1:1 current- balun-choke is ideal. http://www.w5dxp.com/pnts130.gif To my way of thinking (which is probably incorrect), using the 4:1 balun would broaden the impedances that I could match versus the 1:1 balun. What you are saying is just the opposite. Please elaborate. I will be most grateful. A 4:1 balun is a very good transformer over a narrow range. Most are voltage baluns that do not balance currents and therefore do little to discourage common-mode currents. Test a balun looking into 2000+j2000 and see what happens. One of my 4:1 baluns got so hot I couldn't touch the case. The best balun design, IMO, is one where flux in the ferrite is caused only by common-mode current and not by differential-mode current. Here's some useful information: http://www.dxengineering.com/TechArticles.asp?ID={3E5220F7-2D0F-45B5-85F7-3B654F804C4F} -- 73, Cecil *http://www.w5dxp.com The 4:1 balun in the 989c is not a voltage balun. It's fairly hefty current balun wound on a big toroid. I've used the same one when I'm using mine for ladder line. I got my 989c free because of heat damage. But it was fried coil forms, rather than the balun. I tediously repaired the coil, and have been using it ever since. The coil in it is actually the second one. The guy burned up two of them, and finally decided to buy a big Nye Viking, and gave me the 989c as junk trash. But he abused the tuner by trying to run a 1/2 size dipole on 75m, and also running a 8877.. :/ Not a good idea when using a T network tuner.. I guess the Nye Viking was a bit stouter, as I don't recall him killing it. But I bet even it got a bit toasty at times. :( Anyway, being he never managed to kill one of the baluns with his torture tests, I imagine they are fairly stout. It is a "3 KW" tuner.. wink,wink.. :/ |
Installing a Ladder Line to the house
wrote in message ... On Jan 11, 8:59 am, Cecil Moore wrote: Ed Cregger wrote: I have an LDG 1:1 200 watt balun that will tune my Van Gordon All Bander from one end to the other of the HF spectrum, using just the internal tuner of my Yaesu FT-890AT. Go figure. If this is the 80m dipole with 100' of ladder-line, one can look at my notuner all-band-HF antenna to see why 100' is a good fixed length for the ladder-line. 100' is near a current maximum point (loop) on all HF bands. If one varies the length of the ladder-line from 90' to 115', one doesn't even need a tuner and a 1:1 current- balun-choke is ideal. http://www.w5dxp.com/pnts130.gif To my way of thinking (which is probably incorrect), using the 4:1 balun would broaden the impedances that I could match versus the 1:1 balun. What you are saying is just the opposite. Please elaborate. I will be most grateful. A 4:1 balun is a very good transformer over a narrow range. Most are voltage baluns that do not balance currents and therefore do little to discourage common-mode currents. Test a balun looking into 2000+j2000 and see what happens. One of my 4:1 baluns got so hot I couldn't touch the case. The best balun design, IMO, is one where flux in the ferrite is caused only by common-mode current and not by differential-mode current. Here's some useful information: http://www.dxengineering.com/TechArticles.asp?ID={3E5220F7-2D0F-45B5-85F7-3B654F804C4F} -- 73, Cecil http://www.w5dxp.com The 4:1 balun in the 989c is not a voltage balun. It's fairly hefty current balun wound on a big toroid. I've used the same one when I'm using mine for ladder line. I got my 989c free because of heat damage. But it was fried coil forms, rather than the balun. I tediously repaired the coil, and have been using it ever since. The coil in it is actually the second one. The guy burned up two of them, and finally decided to buy a big Nye Viking, and gave me the 989c as junk trash. But he abused the tuner by trying to run a 1/2 size dipole on 75m, and also running a 8877.. :/ Not a good idea when using a T network tuner.. I guess the Nye Viking was a bit stouter, as I don't recall him killing it. But I bet even it got a bit toasty at times. :( Anyway, being he never managed to kill one of the baluns with his torture tests, I imagine they are fairly stout. It is a "3 KW" tuner.. wink,wink.. :/ ----------- Yeah, it's a 3kw tuner when the SWR is 1:1. Lots of folks don't understand that at all. I don't mean to sound like a smart ass, but all of the techno-babble (which I too have memorized) such as current balun - voltage balun - blah-blah-blah, does not help me do what I am trying to do. I've read all of that a thousand times at least, memorized it, passed tests on the fundamentals, etc. It doesn't apply directly in this instance. I'm looking for a way to multiply the range of impedances that can be matched. Yeah, I know. This is not in the handbooks, but it is what I'm trying to do. And, it has been done with the MFJ-989C balun, so I know that it CAN be done. Don't believe me? Operate the 989C direct from a coaxial output into an external balun and then run it through the wire output which has the alleged 4:1 balun in line. The difference in the loads that can be matched is astounding. Problem is, I can no longer enjoyably tune the MFJ-989C due to arthritis. I am looking for a balun that will multiply the impedances that can be matched so that I can use my MFJ and LDG high power autotuners. The stock baluns I have used do not provide this ability with these autotuners. Nor can they be equalled using the MFJ-989C straight thru, without the internal balun in line. Pardon me if I'm repeating myself. Need sleep. What doesn't help is that I'm only using about half of the 100' of 450 ohm twinlead feedline that came with my Van Gordon All Bander. I just have no other way to lengthen it, so I'm stuck using almost fifty feet of the twinlead. I'm sure this compounds the problems that I am having. On top of all of that, I want to be able to run about 600 watts output from my amplifiers (one upstairs/one downstairs). Any thoughts/ideas would be appreciated. I have thought of going with a fan dipole, but that will reduce my operating bands by nearly one half. Ed, N2ECW |
Installing a Ladder Line to the house
On Jan 11, 2:21*pm, "Ed Cregger" wrote:
----------- Yeah, it's a 3kw tuner when the SWR is 1:1. Lots of folks don't understand that at all. I don't mean to sound like a smart ass, but all of the techno-babble (which I too have memorized) such as current balun - voltage balun - blah-blah-blah, does not help me do what I am trying to do. I've read all of that a thousand times at least, memorized it, passed tests on the fundamentals, etc. It doesn't apply directly in this instance. Wasn't meant to.. I was just informing Cecil about the balun in the tuner... On top of all of that, I want to be able to run about 600 watts output from my amplifiers (one upstairs/one downstairs). Any thoughts/ideas would be appreciated. I have thought of going with a fan dipole, but that will reduce my operating bands by nearly one half. Can't really think of anything offhand, unless maybe you built the various ratio baluns, and then used a switch to select which one you want. Palomar used to make some baluns with some different than usual ratios, but I don't think they are still in business, and I think those were only rated for 100w or so. So you might have to make your own to handle power. And even then I'm not sure how well it would pan out. I've never tried doing anything like that, so your guess would probably be as good as mine. Myself, I run the fan dipoles, but I'm not really too worried about working all bands. I tend to stick on the low bands most of the time. I hardly ever get on 20-10 anymore, unless there is a disturbance in the force. :/ But I still can if I want. I can slap the tuner inline and even with the loss, I can still operate fairly well on the "no element" bands. But I hang out on 160/80/40 most the time. In the summer, just 80/40 pretty much.. 40 in the day, 80/75 at night.. So it's not too complicated for me.. :/ The no tune plug n play ease will spoil you. And the system is efficient on the designed bands. Heck, I've got a tower and tri-bander for the high bands. But.. I don't use em here.. The tower is in the garage, and the beam is up in the attic. Shows you how excited I am about 20-10 m these days.. :/ The only time I've ever used that rig is when I've drug it out to a few field days. And being I don't usually work those bands at FD, I still really haven't used it much myself. It won 10m phone one year I think.. :) I wasn't the operator though.. I don't come out of my hole until it gets dark and the low bands come alive. |
Installing a Ladder Line to the house
wrote in message ... On Jan 11, 2:21 pm, "Ed Cregger" wrote: ----------- Yeah, it's a 3kw tuner when the SWR is 1:1. Lots of folks don't understand that at all. I don't mean to sound like a smart ass, but all of the techno-babble (which I too have memorized) such as current balun - voltage balun - blah-blah-blah, does not help me do what I am trying to do. I've read all of that a thousand times at least, memorized it, passed tests on the fundamentals, etc. It doesn't apply directly in this instance. Wasn't meant to.. I was just informing Cecil about the balun in the tuner... On top of all of that, I want to be able to run about 600 watts output from my amplifiers (one upstairs/one downstairs). Any thoughts/ideas would be appreciated. I have thought of going with a fan dipole, but that will reduce my operating bands by nearly one half. Can't really think of anything offhand, unless maybe you built the various ratio baluns, and then used a switch to select which one you want. Palomar used to make some baluns with some different than usual ratios, but I don't think they are still in business, and I think those were only rated for 100w or so. So you might have to make your own to handle power. And even then I'm not sure how well it would pan out. I've never tried doing anything like that, so your guess would probably be as good as mine. Myself, I run the fan dipoles, but I'm not really too worried about working all bands. I tend to stick on the low bands most of the time. I hardly ever get on 20-10 anymore, unless there is a disturbance in the force. :/ But I still can if I want. I can slap the tuner inline and even with the loss, I can still operate fairly well on the "no element" bands. But I hang out on 160/80/40 most the time. In the summer, just 80/40 pretty much.. 40 in the day, 80/75 at night.. So it's not too complicated for me.. :/ The no tune plug n play ease will spoil you. And the system is efficient on the designed bands. Heck, I've got a tower and tri-bander for the high bands. But.. I don't use em here.. The tower is in the garage, and the beam is up in the attic. Shows you how excited I am about 20-10 m these days.. :/ The only time I've ever used that rig is when I've drug it out to a few field days. And being I don't usually work those bands at FD, I still really haven't used it much myself. It won 10m phone one year I think.. :) I wasn't the operator though.. I don't come out of my hole until it gets dark and the low bands come alive. ----------- I may end up doing what you are doing - sort of. I too operate mostly 75 and 40 meters these days. I can put up a vertical for the higher bands. I already have three commercial verticals (some old, one new), so I would still have the capability to operate the higher HF bands, if I wanted to. Thanks for letting me pick your brains. Much appreciated. All of you. Ed, N2ECW |
Installing a Ladder Line to the house
On Thu, 8 Jan 2009 08:50:33 -0500, "Ed Cregger"
wrote: "Dave" wrote in message om... Bob Miller wrote: I've had good luck bringing 450-ohm line through the window using MFJ's 4602 window feed through board. It has ceramic feed through insulators for the balanced line, more feedthrough's for a random wire, three coax lines and a ground wire. Even includes weather stripping and a burgler bar. Bob k5qwg That's through a window, not through a wall. I use the MFJ myself. If I did want to use non-resonant antennas I would locate a tuner at the antenna feedpoint, not at the generator (transmitter). Then you would cheat yourself of a fair amount of propagation and some of the lower and higher frequencies available with such a set up. You're not going to keep RF out of the shack, regardless of which system you use. You might be able to keep some of the hot spots outside, but often times they are close enough to the station that it is really a waste of time. This fascination with resonance is a leftover from CB thinking. How many warships utilize resonant antennas? Yet they communicate the world over. Yes, and they have bevy of antenna tuners to boot. Of course, some radars use resonant antennas. The aversion to transmatches is a ham cultural trait that has no basis in reality, just as the CB'ers are hooked on resonant 50 ohm antennas. It's a characteristic of the culture(s) of both types of operators, with no basis in practical operating engineering. Ed, N2ECW |
Installing a Ladder Line to the house
I'm in the process of finishing the feedline for my 80m dipole,gonna use it for 80/75,40& 30 m, any suggestions for a lengths ?? |
Installing a Ladder Line to the house
On 10/08/2020 01:30, wrote:
I'm in the process of finishing the feedline for my 80m dipole,gonna use it for 80/75,40& 30 m, any suggestions for a lengths ?? ====================== You'll find some wisdom on the matter at http://www.w5dxp.com/notuner.htm Cecil Moore is no doubt the guru on doublets . As per the above ,see his extensive web site. Frank , EI7KS |
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