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Cecil Moore wrote: zeno wrote: seriously, though, if one needed a section of ladder line to really stay put (say a section which gets nervously close to other naughty metal things or wire, why couldn't you fabricate just that section out of copper tubing and then go the rest of the way with wire? Are there impedance issues when changing the wire thickness along the way? I have used solid copper wire sliding inside copper tubing to achieve an adjustable length transmission line for matching purposes. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- That's interesting, so you find wire whose OD is just right for the ID of the tubing and that makes a good enough connection and is adjustable. How much adjustment were you after, inches or feet? -Bill |
zeno wrote:
Cecil Moore wrote: I have used solid copper wire sliding inside copper tubing to achieve an adjustable length transmission line for matching purposes. That's interesting, so you find wire whose OD is just right for the ID of the tubing and that makes a good enough connection and is adjustable. How much adjustment were you after, inches or feet? I just relied on skin effect to effect the proper conductive function. RF won't flow into the inside of the tubing if it has any other "choice". :-) The thing was adjustable from 20 feet to 35 feet in order to make a G5RV truly a fully functional all-HF-band antenna. It really did work nearly perfectly and could be automated using something like a screwdriver motor. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Mon, 19 Apr 2004 00:10:50 GMT, zeno wrote:
Anyone just use lengths of copper pipe or tubing? You might only need a tiny spacer every 5 feet or so. Was that you or someone else who made the ladder line out of tubing shaped like a sine wave.... hi hi seriously, though, if one needed a section of ladder line to really stay put (say a section which gets nervously close to other naughty metal things or wire, why couldn't you fabricate just that section out of copper tubing and then go the rest of the way with wire? Are there impedance issues when changing the wire thickness along the way? 73 Bill Cecil Moore wrote: zeno wrote: I just found several hundered feet of used #10 solid copper, insulated wire, it was pulled out of my well (submersible 240V pump) a few years ago. Any reason, aside from weight, not to use this #10 wire for constructing diy ladder-line? Zeno, all of your suggestions would increase the weight of the feedline, and possibly stretch the antenna. FYI, a 500-ft. spool of #14 or #12 insulated, stranded copper wire from Lowe's Home Improvement (or Home Depot) runs about $15.00 Bob k5qwg Maybe you should patent the idea of a self-supporting transmission line? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Bob Miller wrote: Zeno, all of your suggestions would increase the weight of the feedline, and possibly stretch the antenna. FYI, a 500-ft. spool of #14 or #12 insulated, stranded copper wire from Lowe's Home Improvement (or Home Depot) runs about $15.00 Bob k5qwg Hi Bob, I did pick up a 500' roll of #12 insulated from the Home Depot here (current price here is about $32), but it seems like this braided copper will require too many spacers to keep it straight. I am thinking about returning it for some solid copper #12. I think the solid will hold shape better as a ladder-line with a minimum of spacers. Also I see no reason not to go with bare wire instead of insulated. Can anyone run down the pros and cons of bare vs. insulated for ladder-line. I understand there is ever so slightly less loss with bare wire. Bill |
I tried practicing making some diy ladder line with a couple of
spacers and a variety of wi stranded #12, and solid #12, and then solid #14 (all insulated). I think I am going to pass on this process. The only way I can see this homebrew ladder line holding its shape (spacing configuration) is to keep it under quite a bit of tension, a situation which may not actually be appropriate to my specific installation parameters here. I am now thinking: how bad could those commercially manufactured window lines be? Any recommendations on a specific type of commercially made window (ladder) line? I see that it comes in a variety of configurations and slight differences in Z. This feed line will be for a full wave 160m loop. I am not all that convinced that the effects of weather on this commercially available balanced line would be that much more negative than what it would be with any homebrew line I could construct. I am under the impression that homebrewed ladder line should strive to have as few spacers as possible, eg. 3' for straight runs, 1-2' for curves. Using these guidelines it seems like what I would come up with would not maintain a precise spacing and the temptation would be to use a spacer at every foot. Wouldn't it be undesireable to use so many spacers? Somebody out there must like commercial window ladder line? Bill 'Doc wrote: Larry, Boy, are you gonna have fun! As Cecil said, spacing isn't all that critical. Use whatever you can find enough of, to make the 'spreaders', as long as it's not conductive it should work. The simplest way to feed ladder line through a window is to make a 'spacer' board to fit in the window. Drill a couple of holes in the board, the correct distance apart, feed the line through the holes, 'hot glue' in place (or however you can get it to stay put. Have to remove the screen... 'Doc PS - The real 'trick' is to keep the line from 'swarming' on you when you finish. |
How close do the spacers need to be placed in reality?
http://www.w7fg.com/ant.htm How close do these spacers appear to be. Bill zeno wrote: I tried practicing making some diy ladder line with a couple of spacers and a variety of wi stranded #12, and solid #12, and then solid #14 (all insulated). I think I am going to pass on this process. The only way I can see this homebrew ladder line holding its shape (spacing configuration) is to keep it under quite a bit of tension, a situation which may not actually be appropriate to my specific installation parameters here. I am now thinking: how bad could those commercially manufactured window lines be? Any recommendations on a specific type of commercially made window (ladder) line? I see that it comes in a variety of configurations and slight differences in Z. This feed line will be for a full wave 160m loop. I am not all that convinced that the effects of weather on this commercially available balanced line would be that much more negative than what it would be with any homebrew line I could construct. I am under the impression that homebrewed ladder line should strive to have as few spacers as possible, eg. 3' for straight runs, 1-2' for curves. Using these guidelines it seems like what I would come up with would not maintain a precise spacing and the temptation would be to use a spacer at every foot. Wouldn't it be undesireable to use so many spacers? Somebody out there must like commercial window ladder line? Bill 'Doc wrote: Larry, Boy, are you gonna have fun! As Cecil said, spacing isn't all that critical. Use whatever you can find enough of, to make the 'spreaders', as long as it's not conductive it should work. The simplest way to feed ladder line through a window is to make a 'spacer' board to fit in the window. Drill a couple of holes in the board, the correct distance apart, feed the line through the holes, 'hot glue' in place (or however you can get it to stay put. Have to remove the screen... 'Doc PS - The real 'trick' is to keep the line from 'swarming' on you when you finish. |
On Tue, 20 Apr 2004 06:23:13 GMT, zeno wrote:
Any recommendations on a specific type of commercially made window (ladder) line? I see that it comes in a variety of configurations and slight differences in Z. This feed line will be for a full wave 160m loop. Hi Bill, You repeatedly characterize this as 160M and given the size and height - Why do you think you need ladder line when it will in all probability fit quite nicely into a coax? In free space, it may show as much as 140 Ohms R; however, within the cold embrace of earth only 50 feet away, you will barely muster 35 Ohms at resonance. 73's Richard Clark, KB7QHC |
zeno wrote:
Any recommendations on a specific type of commercially made window (ladder) line? I see that it comes in a variety of configurations and slight differences in Z. I use Wireman #554, #14, stranded, copper-clad steel. It's virtually indestructible. http://www.thewireman.com -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
zeno wrote:
http://www.w7fg.com/ant.htm How close do these spacers appear to be. Using a tape measure, they appear to be 21 inches apart. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
zeno wrote:
I tried practicing making some diy ladder line... I am now thinking: how bad could those commercially manufactured window lines be? Any recommendations on a specific type of commercially made window (ladder) line? I used 300 ohm TV twin lead for years. Why the concern about 600 ohms? It really doesn't matter unless you have a 600 Ohm feedpoint. The losses are still very low regardless of conditions, and as for dirty or rain, I had some up from 1983 to 1996 -- and never noticed any changes. When I took the antenna down the twinlead was as good as new and I used it for other things. Irv VE6BP -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/ Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/ Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/ -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
Irv Finkleman wrote:
I should have added that the Twin Lead was the cheapest stuff available as I just tried it for an experiment! It was a 60 foot run as well! Irv -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/ Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/ Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/ -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
Irv Finkleman wrote:
I used 300 ohm TV twin lead for years. Why the concern about 600 ohms? It really doesn't matter unless you have a 600 Ohm feedpoint. The losses are still very low regardless of conditions, and as for dirty or rain, I had some up from 1983 to 1996 -- and never noticed any changes. When I took the antenna down the twinlead was as good as new and I used it for other things. Here's the 600 ohm concern. A dipole's feedpoint is likely to vary from about 60 ohms min to about 6000 ohms max. With 300 ohm line, the SWR varies from 5:1 to 20:1. With 600 ohm line, the SWR is relatively constant at 10:1, i.e. 600 ohm line gives more consistent SWRs over the entire HF range than does 300 ohm line - just my two cents. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Hi Richard,
My beginner's understanding is that I would have a better multi-band antenna utilizing a balanced feedline than with coax. I had seen a couple of recommendations by doing internet searches. Several operators spoke highly of the ~540' loop with balanced feed. I have a nice old 250W Johnson matchbox on hand. Again, my beginner's understanding, the more wire=the better, so I figured this long loop would be a good antenna for "all" bands. I am just now setting up a station for the first time. I need to think I know what I am doing long enough to simply put something into action for fear I will spend forever in a complex endless decision making matrix. I enjoy trips to the hardware store and the junkyard, I haven't even been on the air yet......(or at least since 1953....). I figure antenna concerns are first, a good ground, then I need to think about some serious equipment. This can be a bit overwhelming. Ihis next Sat. I will be going to a local hamfest (my first one), hopefully to meet some locals and make friends (mentor's, Elmers, etc.), also to track down the guy with the bow and arrow who can get a line up my Eucalyptus tree (165'+) for another possible antenna in an alternate shack on the property...... actually, now that I think of it, my whole involvement in ham radio at this moment (besides the fun of studying for the exams last month) is dreaming of antenna farm. just the other night while listening to some local maniacs on 3840, now I realize I need to get my Extra if I want to be able to chime in at that frequency.....those guys last night almost shattered my naive expectation that hams are always gentlmen, a pursuit of integrity I personaly fully intend to promote in my own operating demeanor. Apparently there is some "famous" AM talk show host involved with that little late night net..... shame on them.... Great, now I have a shopping mission.....go out and buy the Extra exam book.....I do actually enjoy studying and learning..... Now....a trip to the junk yard to find an old fashion DPDT Knife switch I can mount on the wall so I can switch my incoming balanced line from the Johnson to the Kenwood tuner.... help!..... 73 Bill (KG6UHM) Richard Clark wrote: On Tue, 20 Apr 2004 06:23:13 GMT, zeno wrote: Any recommendations on a specific type of commercially made window (ladder) line? I see that it comes in a variety of configurations and slight differences in Z. This feed line will be for a full wave 160m loop. Hi Bill, You repeatedly characterize this as 160M and given the size and height - Why do you think you need ladder line when it will in all probability fit quite nicely into a coax? In free space, it may show as much as 140 Ohms R; however, within the cold embrace of earth only 50 feet away, you will barely muster 35 Ohms at resonance. 73's Richard Clark, KB7QHC |
Hi Cecil,
I will check that out. While playing around with wire last night, seriously, the diy that looked like it would work best was the sample I put together with some #10 bare copper! I have been known to end up doing things the hard way, and overdoing things.... so why not this #10 bare copper ladder line? 73, Bill Cecil Moore wrote: zeno wrote: Any recommendations on a specific type of commercially made window (ladder) line? I see that it comes in a variety of configurations and slight differences in Z. I use Wireman #554, #14, stranded, copper-clad steel. It's virtually indestructible. http://www.thewireman.com -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Hi Irv,
The 300 ohm TV line I am sure works, but it does not appeal to my tendency to want to make everything "industrial strength" as if we were all going to live for ever. I am finding it difficult at the moment to resist the idea of making my ladder line out of #10 bare copper, thus insuring I will have a *&^%$#@!!!!! time up on top of a ladder yelling and screaming things like ("why do I always make things so difficult) hi hi. Actually I think that the #10 bare copper ladder line with my secret hardware store insight spacers will look impressive.... (who am I trying to impress is the question) I need to get my butt on the air otherwise I be only a "theoretical" ham..... Secret hardware store spacer insight: the 4" uv/pvc ferrules that come with the gutter spikes!....no I didn't say gutter snipes.....hi 73 everyone was working this guy in Lithuania on 20m this morning....can't wait to get in there...... fun..... Bill Irv Finkleman wrote: zeno wrote: I tried practicing making some diy ladder line... I am now thinking: how bad could those commercially manufactured window lines be? Any recommendations on a specific type of commercially made window (ladder) line? I used 300 ohm TV twin lead for years. Why the concern about 600 ohms? It really doesn't matter unless you have a 600 Ohm feedpoint. The losses are still very low regardless of conditions, and as for dirty or rain, I had some up from 1983 to 1996 -- and never noticed any changes. When I took the antenna down the twinlead was as good as new and I used it for other things. Irv VE6BP -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/ Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/ Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/ -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
Cecil Moore wrote:
Irv Finkleman wrote: I used 300 ohm TV twin lead for years. Why the concern about 600 ohms? It really doesn't matter unless you have a 600 Ohm feedpoint. The losses are still very low regardless of conditions, and as for dirty or rain, I had some up from 1983 to 1996 -- and never noticed any changes. When I took the antenna down the twinlead was as good as new and I used it for other things. Here's the 600 ohm concern. A dipole's feedpoint is likely to vary from about 60 ohms min to about 6000 ohms max. With 300 ohm line, the SWR varies from 5:1 to 20:1. With 600 ohm line, the SWR is relatively constant at 10:1, i.e. 600 ohm line gives more consistent SWRs over the entire HF range than does 300 ohm line - just my two cents. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- Understood, Cecil, but when the SWR losses are of so little concern then the SWR consistency becomes likewise, at least IMHO. Irv -- -------------------------------------- Diagnosed Type II Diabetes March 5 2001 Beating it with diet and exercise! 297/215/210 (to be revised lower) 58"/43"(!)/44" (already lower too!) -------------------------------------- Visit my HomePage at http://members.shaw.ca/finkirv/ Visit my Baby Sofia website at http://members.shaw.ca/finkirv4/ Visit my OLDTIMERS website at http://members.shaw.ca/finkirv5/ -------------------- Irv Finkleman, Grampa/Ex-Navy/Old Fart/Ham Radio VE6BP Calgary, Alberta, Canada |
Understood, Cecil, but when the SWR losses are of so little concern
then the SWR consistency becomes likewise, at least IMHO Hi Irv, Excellent point! Although I am sure Cecil put it in there as Point/Counterpoint. 73 Gary N4AST |
zeno wrote:
so why not this #10 bare copper ladder line? For one thing, it is overkill. And if it is solid, it is subject to failure from fatigue. Many, many hams have had trouble with breakage of solid wire ladder-line. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
JGBOYLES wrote:
Understood, Cecil, but when the SWR losses are of so little concern then the SWR consistency becomes likewise, at least IMHO Hi Irv, Excellent point! Although I am sure Cecil put it in there as Point/Counterpoint. If the SWR on 300 ohm twinlead is 5:1, the impedance at the current maximum point is 60 ohms. If the SWR on 300 ohm line is 20:1, the impedance at the current maximum point is 150 ohms (3:1 SWR). If the SWR on 600 ohm line is 10:1, the impedance at the current maximum point is 60 ohms NO MATTER WHAT THE ANTENNA IMPEDANCE. The impedance at the current maximum point for a 6000 ohm antenna fed with 600 ohm line is the same as the impedance at the current maximum point for a 60 ohm antenna fed with 600 ohm line. That's a definite '+' in my book. I like 60 ohms better than 150 ohms. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Hi Cecil,
The only reason I was considering #10 solid wire was because it would absolutely hold its shape with a minimum of spacers. Aside from the fact that it is electrically overkill, you are saying that even wire that thick could possible flex enough over time to fatique and fail? Somehow I got it into my head that the best way to go was homebrew ladder line, and the only way I could see doing it myself was with this thick wire, all other wires were too messy somehow. I checked the #554 that you suggested and it is rated for full power. I didn't realize that #14 wire could handle that (guess I have AC wiring in mind and not RF). So you have come to the conclusion that this wire is the best way to go for balanced feed line all things considered? (weather, dirt, etc.) Maybe I should just use that and move on from this obsession about making my own ladder line. I'll tell you that #10 was going to look cool in a kind of science fiction movie laboratory kind of way..... It is hard to get off that track, but maybe I am not being very practical... I see that Radio Works also has this #14 copper-clad for about the same price, he says that the actual impedance is approx. 390 ohms. Now I am wondering how I got onto this do it yourself homebrew ladder line obsession in the first place, I think it was some folks complaining about how erratic it was with the rainy weather and when it gets dirty, and stories of oldtimers going out and coating it with bacon fat etc. yuk..... So you are predicting eventual unhappiness with #10 bare copper wire ladder line with cute little gutter spike uv/pvc ferrules as spacers. Why do all those guys make their own ladder line...is it because the commercial version is nearly 30 cents a foot? Or is there some other downside they were trying to avoid? I was going to order some stuff from Radio Works anyway, so I could just get a chunk of that #14 ladder line......unless ....... Zeno (can't seem to really get away from this nickname....so maybe Bill will just have to wait in the wings.....) Cecil Moore wrote: zeno wrote: so why not this #10 bare copper ladder line? For one thing, it is overkill. And if it is solid, it is subject to failure from fatigue. Many, many hams have had trouble with breakage of solid wire ladder-line. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Hi Richard, You remind me that I do not understand something. Let's say the characteristic impedance of this 540' loop is in the neighborhood of 140 ohms in free space, or even as you say closer to even 35 ohms in reality. Your point was, if I understand correctly, that this is in the ballpark of 50ohm coax and you suggest it can just as easily be fed into the coax. But I thought that coax is unbalanced and the point was to go with a balanced feed line? I guess I am not understanding the relevant differences between balanced vs. unbalanced feedlines, and getting the impedance of the the transmission line close to the impedance of the antenna. I thought the point of my striving to use balanced ladder line was to somehow gain something that would be compromised by using coax. I thought that the the ladder line which might be 488 ohms say is still going to be a better feedline than using the 50ohm coax. The coax would still then require a balun, correct? (a 1:1 banlun?). It is sites like this: http://www.cebik.com/par.html that tend to get one thinking about this whole diy approach. My reading and gleaning of websites has me of the opinion (at this point) that the balanced line with this long loop is better (multi band) than to feed it with coax. I believe Cecil has already explained this in terms of the wide range of actual resistance that may be encountered multi band. (hey, I am just now learning to talk this lingo....just barely know what I am talking about....operating intuitively, and with the kindness of strangers....... Zeno (aka Bill) KG6UHM for the moment..... Richard Clark wrote: On Tue, 20 Apr 2004 06:23:13 GMT, zeno wrote: Any recommendations on a specific type of commercially made window (ladder) line? I see that it comes in a variety of configurations and slight differences in Z. This feed line will be for a full wave 160m loop. Hi Bill, You repeatedly characterize this as 160M and given the size and height - Why do you think you need ladder line when it will in all probability fit quite nicely into a coax? In free space, it may show as much as 140 Ohms R; however, within the cold embrace of earth only 50 feet away, you will barely muster 35 Ohms at resonance. 73's Richard Clark, KB7QHC |
zeno wrote:
So you have come to the conclusion that this wire is the best way to go for balanced feed line all things considered? Not the best, but hard to beat for the price and convenience. So you are predicting eventual unhappiness with #10 bare copper wire ladder line ... The solid copper wire usually breaks at the antenna where there is lots of lateral movement. That can probably be cured by a rigid center support. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Wed, 21 Apr 2004 05:40:11 GMT, zeno wrote:
You remind me that I do not understand something. Let's say the characteristic impedance of this 540' loop is in the neighborhood of 140 ohms in free space, or even as you say closer to even 35 ohms in reality. Your point was, if I understand correctly, that this is in the ballpark of 50ohm coax and you suggest it can just as easily be fed into the coax. But I thought that coax is unbalanced and the point was to go with a balanced feed line? Hi Bill, True, but easily answered with a feed line choke (1:1 BalUn) at the drive point that will render the coax balanced if the load is - being that close to ground there is every chance that may be debatable. Again, there is no getting it right the first time out of the box - you can only put it up and test to see how much you need to change it. You were planning pulleys right? I guess I am not understanding the relevant differences between balanced vs. unbalanced feedlines, and getting the impedance of the the transmission line close to the impedance of the antenna. You can build a twin line of 50 Ohms. Takes pretty close spacers, and you will need a lot if you use bare wire. The wire pairs would be as close as zip cord. Twisted pair, insulated could do the trick (might even match the 35 Ohms). I thought the point of my striving to use balanced ladder line was to somehow gain something that would be compromised by using coax. I thought that the the ladder line which might be 488 ohms say is still going to be a better feedline than using the 50ohm coax. Well.... Only if you use this as a monobander. As a multibander it will ALWAYS have SWR, the point of big wire twin lead is that the loss will be less than if you used the same antenna with coax feeding it. Coax with big center wire is HUGE and COSTLY for the same loss figures at the same SWRs met by multiband use. For 160M band, I would REALLY look for the Archer and put my effort into that prospect. A low loop is the pits - hi Z, lo Z, balanced, unbalanced, SWR, no SWR hardly counts for diddly. The coax would still then require a balun, correct? (a 1:1 banlun?). ibid. It is sites like this: http://www.cebik.com/par.html that tend to get one thinking about this whole diy approach. My reading and gleaning of websites has me of the opinion (at this point) that the balanced line with this long loop is better (multi band) than to feed it with coax. True enough. I simply responded to you describing it as a 160M loop. If it was a dedicated monobander, twin lead is extravagant and forces unnecessary SWR into the picture. I believe Cecil has already explained this in terms of the wide range of actual resistance that may be encountered multi band. (hey, I am just now learning to talk this lingo....just barely know what I am talking about....operating intuitively, and with the kindness of strangers....... Stella! (Oops, wrong "Streetcar"). 73's Richard Clark, KB7QHC |
Richard Clark wrote: You were planning pulleys right? yes indeed, lots of pulleys, I only want to be putting up these masts once. For 160M band, I would REALLY look for the Archer and put my effort into that prospect. A low loop is the pits - hi Z, lo Z, balanced, unbalanced, SWR, no SWR hardly counts for diddly. I am going to meet the archer this weekend at the hamfest in Sonoma. Another friend is giving me a homebuilt house trailer (quaint gypsy wagon) which I can park out in the back 40 as an alt. shack which will be close to the antenna up in the 200' Eucalyptus tree. It is not that I am particularly excited about 160m (although good to be able to operate there when necessary I guess), but HEIGHT is everything, right? I believe Cecil has already explained this in terms of the wide range of actual resistance that may be encountered multi band. (hey, I am just now learning to talk this lingo....just barely know what I am talking about....operating intuitively, and with the kindness of strangers....... Stella! (Oops, wrong "Streetcar"). Wow, a cinematically (literary) erudite ham, cool....I feel like I am home..... Zeno (aka Bill) KG6UHM (until further notice.....) |
Richard Clark wrote: For 160M band, I would REALLY look for the Archer and put my effort into that prospect. A low loop is the pits - hi Z, lo Z, balanced, unbalanced, SWR, no SWR hardly counts for diddly. OK, the 540' loop will be up as high as I can get it with these telescoping masts, somewhere between 45-55 feet at each corner. How will this be for bands other than 160m (either with the Johnson or my Kenwood ATU (+current type balun)? As mentioned I have the real estate to try several antennas here. I am curious to find out how the loop will work. I only call it 160m because of the length of the wire. There were a handful of websites expressing enthusiasm about this antenna. Another plan is some kind of antenna on a rotator. Any ideas of how to engineer some kind of beam (light-weight) or something similar atop one of these 50' telescoping tv masts? If I am to telescope 4 - ten foot sections, the antenna and rotator would have to be light. I would have to engineer this with a crew of buddies holding the guy ropes as the stong person is up ten feet trying to push up this whole thing into the air a section at a time. Anyone done this? The motivation here is 1) I have the 50 mast, so economy is a factor, and 2) the result will look more like some kind of elaborate tv antenna. A tower out in the front yard might be a bit much in the neighborhood at this point. I need to test these waters first. |
On Wed, 21 Apr 2004 19:33:03 GMT, zeno wrote:
OK, the 540' loop will be up as high as I can get it with these telescoping masts, somewhere between 45-55 feet at each corner. How will this be for bands other than 160m (either with the Johnson or my Kenwood ATU (+current type balun)? As mentioned I have the real estate to try several antennas here. Hi Bill, Above 80M it should be gangbusters. However, you may wish to look into Rhombic designs given the vast footprint available to you to experiment with. This will be more directional, more gain for the 30M bands and above, so you will want to investigate what direction that should be (don't guess using a flat map either). It would be roughly the same shape, only more diamond than haphazard square. Such a design shouldn't hurt your 160M loop prospects, but would optimize the higher bands (where formerly you were just going to take what came with the turf). With a lot more wire (and work), you could get into the Fish Bone Array, or a wire Log Periodic Array. Both would, again, be fixed direction so planning ahead is again seen in the XTAL ball. I am curious to find out how the loop will work. I only call it 160m because of the length of the wire. There were a handful of websites expressing enthusiasm about this antenna. What choice did they have? Such is the fallacy of testimonial. As the saying goes, if all you have is a hammer, everything looks like a nail. Another plan is some kind of antenna on a rotator. Any ideas of how to engineer some kind of beam (light-weight) or something similar atop one of these 50' telescoping tv masts? That would have to be WARC bands and 10M, probably; otherwise you are dreaming in technicolor and surround-sound. 73's Richard Clark, KB7QHC |
zeno wrote:
Another plan is some kind of antenna on a rotator. Any ideas of how to engineer some kind of beam (light-weight) or something similar atop one of these 50' telescoping tv masts? Check out Worldradio's SD-20 systems at http://www.wr6wr.com -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Hi Richard,
Above 80M it should be gangbusters. However, you may wish to look into Rhombic designs given the vast footprint available to you to experiment with. This will be more directional, more gain for the 30M bands and above, so you will want to investigate what direction that should be (don't guess using a flat map either). It would be roughly the same shape, only more diamond than haphazard square. Such a design shouldn't hurt your 160M loop prospects, but would optimize the higher bands (where formerly you were just going to take what came with the turf). Although I have the acres (7) there are a lot of buildings (old barns etc.), trees, etc. My antenna planning has to dodge many many obstacles actually. This is an old chicken ranch and there are building everywhere, then all the trees. Are you saying that a rhombic could be put up on the same masts more or less (only one of the masts is potentially moveable, meaning that it would only be diamond like at one end of the trapezoid. This rhombic would be instead of the 540' loop? I will look up rhombic in the books and see what gives. With a lot more wire (and work), you could get into the Fish Bone Array, or a wire Log Periodic Array. Both would, again, be fixed I will look these up as well. I don't want to get so complex and over my head that I will be overwhelmed. Now that I have the call sign of choice, I am ready to rock and roll..... -Bill (aka Zeno) Hey I got it!!! I am now K6TAJ, Tango Alpha Juliet. The old bongo drummer morse code tapper in me is tickled DAH, DI-DAH, DI-DAH-DAH-DAH is so cool for me for a variety of esoteric reasons, aside from the fact that it is fun to tap out. My second choice was my 1953 call K6CCG (also fun to tap, but not as fun as TAJ, the new call is shorter as well), also I like tango alpha juliet more than charlie charlie golf.....I don't really own any checkered pants..... I actually found myself listed in an old 1958 call book, which actually was the year my old Tech ran out..... Hopefully I can make up for lost time...... 73 Bill, K6TAJ |
roger, tnx Ceece.
I apologize for the Beany reference....I am just elated at getting k6taj. Cecil Moore wrote: zeno wrote: Another plan is some kind of antenna on a rotator. Any ideas of how to engineer some kind of beam (light-weight) or something similar atop one of these 50' telescoping tv masts? Check out Worldradio's SD-20 systems at http://www.wr6wr.com -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
zeno wrote:
Hey I got it!!! I am now K6TAJ, Tango Alpha Juliet. Now we will have an endless thread of words to match your TLA (three letter acronym). Transmitting All Joules? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On Wed, 21 Apr 2004 20:47:47 GMT, zeno wrote:
Although I have the acres (7) there are a lot of buildings (old barns etc.), trees, etc. My antenna planning has to dodge many many obstacles actually. This is an old chicken ranch and there are building everywhere, then all the trees. Are you saying that a rhombic could be put up on the same masts more or less (only one of the masts is potentially moveable, meaning that it would only be diamond like at one end of the trapezoid. This rhombic would be instead of the 540' loop? I will look up rhombic in the books and see what gives. Hi Bill, No, this time shape matters as it is a function of all angles of radiation combining to ADD rather than jumble. Again, think in terms of the supports/mast merely being the outer, irregular perimeter to an ordered interior antenna shape. The Rhombic would BE the 540' loop. Normally it is open or terminated at the end opposite the feed point, but having the shape anticipated is more the work than this simple change. (It has the same feed considerations, complete with your expected twin lead.) Congrats on your desired call. 73's Richard Clark, KB7QHC |
for starters a good contest alternative: Toronto Alaska Japan
and for the hometown crew: Tasty Apricot Jelly or Typical Antique Junk Cecil Moore wrote: zeno wrote: Hey I got it!!! I am now K6TAJ, Tango Alpha Juliet. Now we will have an endless thread of words to match your TLA (three letter acronym). Transmitting All Joules? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
The problem, as I see it, with using the fixed masts as outside perimeter
configuration support structure for the specifically ordered interior shape is the sag the inevitably occurs when wire is a rope and pulley distance away from the supporting mast. I already see this with the tree supported antenna. The ropes drop down and the wire is 8' or so lower than anticipated. This seems critical when the masts are only 50' to begin with. How high, or shouls I say, what is the minimum height for an acceptable Rhombic? Bill, K6TAJ Richard Clark wrote: On Wed, 21 Apr 2004 20:47:47 GMT, zeno wrote: Although I have the acres (7) there are a lot of buildings (old barns etc.), trees, etc. My antenna planning has to dodge many many obstacles actually. This is an old chicken ranch and there are building everywhere, then all the trees. Are you saying that a rhombic could be put up on the same masts more or less (only one of the masts is potentially moveable, meaning that it would only be diamond like at one end of the trapezoid. This rhombic would be instead of the 540' loop? I will look up rhombic in the books and see what gives. Hi Bill, No, this time shape matters as it is a function of all angles of radiation combining to ADD rather than jumble. Again, think in terms of the supports/mast merely being the outer, irregular perimeter to an ordered interior antenna shape. The Rhombic would BE the 540' loop. Normally it is open or terminated at the end opposite the feed point, but having the shape anticipated is more the work than this simple change. (It has the same feed considerations, complete with your expected twin lead.) Congrats on your desired call. 73's Richard Clark, KB7QHC |
On Thu, 22 Apr 2004 00:20:50 GMT, zeno wrote:
The problem, as I see it, with using the fixed masts as outside perimeter configuration support structure for the specifically ordered interior shape is the sag the inevitably occurs when wire is a rope and pulley distance away from the supporting mast. I already see this with the tree supported antenna. The ropes drop down and the wire is 8' or so lower than anticipated. This seems critical when the masts are only 50' to begin with. How high, or shouls I say, what is the minimum height for an acceptable Rhombic? Hi Bill, Think positively: how high will they be? 40 Feet? 10 Meters? One quarter wave for 40M? This is not a hardship case. One half wave or better high for 20M and above? No one's gonna let you cry in your beer there either. And now for the classic "testimonial": it's gonna be boomin! (what choice do you have?). As a cautionary, don't try to pull out the catenary. The tension rises with the tangent of the of the deflection angle. If you could achieve perfect flatness, a breeze would snap the line. 73's Richard Clark, KB7QHC |
ladder line construction methods?
What are the units of distance? Inches? CM? MM? For 300 ohm ladder line, I get .390. Thanks On Tuesday, March 30, 2004 at 8:43:04 PM UTC-5, Tom Bruhns wrote: Impedance is about 120*ln(2*D/d) ohms, where ln is the natural logarithm, and D is the wire spacing, center to center, and d is the wire diameter. Assumes round wires, and air dielectric. You can rearrange that: if you want x ohms and have d diameter, D = d*exp(x/120)/2, where exp(x/120) is "e to the x/120 power". If you don't have a calculator that handles that sort of math, this table will probably get you close enough: D/d impedance, ohms 1.9 150 2.8 200 6.2 300 22 450 75 600 Construction depends a bit on how much you're making and what you have available for materials and tools. People used to use wooden spacers, boiled in parafin wax. Someone gave me a bunch of PETE tensile-strength test strips that are a good size. You can make spacers from PVC pipe. You can thread wires through holes (generally not so efficient), or fit wires into notches and secure by with a plastic or wire wrap, or by melting the wire into an undersized notch, or with various glues. Undoubtedly lots of other ideas, both tried-and-true and just waiting to be tried for the first time. You can drill holes through the glass and install feedthroughs (but probably not if it's double-pane!), or drill a couple over-size holes through the wall or possibly through a wooden window frame member, or install a wood or plastic piece in a partially-open window. You can also possibly inductively or capacitively couple through the window. If you decide to go through wood or wall materials, plan to make oversized holes, lined with decent electrical/RF insulation. What strikes your fancy? Cheers, Tom Larry Gagnon wrote in message ... Hello to all. I intend to erect an 80 meter full size dipole and feed it with homebrew open ladder line. Would anyone care to reply as to how to construct ladder line easily and effectively? How does one determine spacing to get X ohms impedance line? Also any ideas on how such line can easily be fed in through a window with a wood frame would be greatly appreciated. Larry Gagnon VE7EA |
ladder line construction methods?
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