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#1
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Dummy Load Antenna
Has anyone ever tried putting a dipole antenna up with the center insulator
being a high power 50 ohm dummy load,then connecting the dipole elements across the dummy load.This would always keep a suitable match at 50 ohms and satisfy the transceiver.Would most of the power go to the dummy load and not the elements and wouldn't radiate.In thinking about this it all logically makes sense the load would really never change or would it have some reactance with the dipole elements. Thanx All Howard VE4ISP |
#2
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Dummy Load Antenna
Howard,
Yes. Been some years ago now, but there was even a commercial version sold (did pretty well too). Wish I could remember the name of that thingy. - 'Doc |
#3
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Dummy Load Antenna
Howard Kowall wrote:
Has anyone ever tried putting a dipole antenna up with the center insulator being a high power 50 ohm dummy load,then connecting the dipole elements across the dummy load. Yes. There was a commercial antenna quite a few years ago that did just that. I think QST did a review on it. It wasn't advertised as a resistor across the end of the coax, but they either tore the thing apart or X-rayed it, and there it was. This would always keep a suitable match at 50 ohms and satisfy the transceiver. Would most of the power go to the dummy load and not the elements and wouldn't radiate.In thinking about this it all logically makes sense the load would really never change or would it have some reactance with the dipole elements. I guess, But, and hold on to your hat... 50 ohms SWR is not an indication that an antenna works at all, much less that it works well! Imagine where the power is going to and what it is becoming. To the resistor, and it is becoming heat. Anything that is radiated is almost an accident. - 73 de Mike N3LI - |
#4
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Dummy Load Antenna
"Howard Kowall" wrote in message
... Has anyone ever tried putting a dipole antenna up with the center insulator being a high power 50 ohm dummy load,then connecting the dipole elements across the dummy load.This would always keep a suitable match at 50 ohms and satisfy the transceiver.Would most of the power go to the dummy load and not the elements and wouldn't radiate.In thinking about this it all logically makes sense the load would really never change or would it have some reactance with the dipole elements. Thanx All Howard VE4ISP It's lossy, but antenna tuners might be too much fiddling. |
#5
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Dummy Load Antenna
On Wed, 8 Oct 2008 08:11:04 -0500, Howard Kowall wrote:
Has anyone ever tried putting a dipole antenna up with the center insulator being a high power 50 ohm dummy load,then connecting the dipole elements across the dummy load. This would always keep a suitable match at 50 ohms and satisfy the transceiver. You seem to understand nothing about parallel resistances/reactances. |
#6
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Dummy Load Antenna
On Wed, 8 Oct 2008 08:11:04 -0500, "Howard Kowall"
wrote: Has anyone ever tried putting a dipole antenna up with the center insulator being a high power 50 ohm dummy load,then connecting the dipole elements across the dummy load.(...) There was some phony antenna that when tested turned out to be nothing but a resistor across the feed point. Google search and my fading memory couldn't recall the name. The VSWR was great, but nothing else about the antenna was useful, probably due to all your RF power being dissipated in the 50 ohm load instead of being radiated by the antenna. A squashed rhombic with an approximately 500 ohm resistor does have some proponents. See: http://www.hard-core-dx.com/nordicdx/antenna/wire/t2fd.html http://www.hard-core-dx.com/nordicdx/antenna/wire/t2design.html http://en.wikipedia.org/wiki/T2FD_Antenna Search Google for "T2FD antenna". -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
#7
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Dummy Load Antenna
Howard Kowall wrote:
Has anyone ever tried putting a dipole antenna up with the center insulator being a high power 50 ohm dummy load,then connecting the dipole elements across the dummy load.This would always keep a suitable match at 50 ohms and satisfy the transceiver.Would most of the power go to the dummy load and not the elements and wouldn't radiate.In thinking about this it all logically makes sense the load would really never change or would it have some reactance with the dipole elements. Thanx All Howard VE4ISP When you run a 73 ohm "resistor" and a 50 ohm resistor in parallel? You would need a balun (rf transformer) to match to that antenna ... Then you would need a suitable name for it. Let me see, we are mating up a "dummy load" with a "dipole." How about "Dummy-Pole?" grin Regards, JS |
#8
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Dummy Load Antenna
Howard Kowall wrote:
Has anyone ever tried putting a dipole antenna up with the center insulator being a high power 50 ohm dummy load,then connecting the dipole elements across the dummy load.This would always keep a suitable match at 50 ohms and satisfy the transceiver.Would most of the power go to the dummy load and not the elements and wouldn't radiate.In thinking about this it all logically makes sense the load would really never change or would it have some reactance with the dipole elements. Thanx All Howard VE4ISP You would probably be better off loss-wise just using 1000' of RG58 feedline......same result; lots of loss, low SWR. Rick - W7RT |
#9
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Dummy Load Antenna
You're probably thinking of the B&W multi-band folded dipoles.
Very expensive. Great SWR. -- -larry K8UT wrote in message ... Howard, Yes. Been some years ago now, but there was even a commercial version sold (did pretty well too). Wish I could remember the name of that thingy. - 'Doc |
#10
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Dummy Load Antenna
On Wed, 08 Oct 2008 10:07:03 -0700, John Smith
wrote: You would need a balun (rf transformer) to match to that antenna ... Then you would need a suitable name for it. Let me see, we are mating up a "dummy load" with a "dipole." How about "Dummy-Pole?" grin Been there, done that. About 30 years ago, I went on a field day exercise where one of the HF stations was running a lightbulb on a pole for an antenna. 100 watts RF, about 50ft of RG-8/u, voltage stepped down with some kind of xfomer or balun, and a 150 watt incandescent light bulb. I don't recall how well they did, but I could see that the log was filling with contacts. Who needs an antenna anyway? -- Jeff Liebermann 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558 |
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