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#1
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Hi All,
I am looking for my "perfect antenna". It should work on 75m-6m, with NVIS on 75m & 40m and good DX for 20m and above. Above all it must fit in my backyard which is 34 by 50 feet. The use of a tuner and/or balanced line is fine. By perfect, I mean an antenna that gets the RF out (reasonable efficiency as a percentage). At first, I considered a random loop of 34 ft by 50 ft, at about 20 to 30 feet high, with window line, but am having second thoughts. Any ideas or suggestions? Randy KA4NMA |
#2
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try putting up the loop anyway...and opening it opposit of the feedpoint for
use on 80 meters. I will probably work just fine. "Theplanters95" wrote in message ... Hi All, I am looking for my "perfect antenna". It should work on 75m-6m, with NVIS on 75m & 40m and good DX for 20m and above. Above all it must fit in my backyard which is 34 by 50 feet. The use of a tuner and/or balanced line is fine. By perfect, I mean an antenna that gets the RF out (reasonable efficiency as a percentage). At first, I considered a random loop of 34 ft by 50 ft, at about 20 to 30 feet high, with window line, but am having second thoughts. Any ideas or suggestions? Randy KA4NMA |
#3
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#4
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I had a loop that was about 200 feet, and it was triangular.
The only reason I took it down was that the way my trees had grown it was getting tangled on a regular basis. Fed it with 300 ohm tv line. Several different tuners WITHOUT a balun worked fine on the loop. I also used a Balanced (Johnson matchbox) tuner on the loop with good results. John KA9CAR "KC1DI" wrote in message ... On 03 Mar 2004 06:35:41 GMT, ospam (Theplanters95) wrote: Hi All, I am looking for my "perfect antenna". It should work on 75m-6m, with NVIS on 75m & 40m and good DX for 20m and above. Above all it must fit in my backyard which is 34 by 50 feet. The use of a tuner and/or balanced line is fine. By perfect, I mean an antenna that gets the RF out (reasonable efficiency as a percentage). At first, I considered a random loop of 34 ft by 50 ft, at about 20 to 30 feet high, with window line, but am having second thoughts. Any ideas or suggestions? Randy KA4NMA Randy , I Think the loop would work well for you under the perameters you mentioned.. it should be good NVIS on 80 & 40 and begin to show low angle radiation above those bands. you may have to do so work to get it load well for you on 80m though it's a bit short there.. I've use a 520' Horizontal loop here for number of years with good results.. it averages about 30' above ground. 73 Dave |
#5
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Nomen Nescio wrote:
In article ospam (Theplanters95) wrote: I'd love to see this thread expand to answers. Many of us have the same wants, maybe not all the bands, but a least 80-10 in the confines given above. Many solve with a vertical but I for one, would like something better. This has been covered before but bears repeating. Consider a 40m full-wave square loop of about 138 feet, about 34 ft. per side. If an insulator is installed halfway around the loop from the feedpoint, the antenna becomes 1/2WL on 80m. Figure out an easy way to short the insulator out for 40m-10m operation and open the circuit at the insulator for 80m operation. Three possibilities come to mind. Locate the insulator on a pulley on one of the support poles and lower that point on the antenna for physical access. Shouldn't take more than 5 minutes to accomplish the short/open function. Install a 1/4WL shorted stub for 80m operation. That will give an open circuit on 80m and a short circuit on any multiple of 3.8 MHz, for instance. I once rigged up a Rube Goldberg high voltage switch out of copper tubing supported by PVC pipe. One end of the antenna was attached to a piece of 1/2 inch copper tubing. The other end was attached to a piece of 1/4 inch copper tubing. By tugging on one of two strings, I could move the 1/4" tubing in or out of the 1/2" tubing. More elegant than strings would be a small screwdriver motor powered by +/- DC from the shack end of the 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! =----- |
#6
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Yes Cec, to use a vertical 1/4-wave line is a neat way of shorting and
opening a horizontal wire at a single frequency from ground level. I once used a sealed reed relay to do a similar job. One of the horizontal antenna wires was in fact twin 20-gauge speaker cable to operate the relay coil. The shack end of the twin wire required a bifilar choke wound on a ferrite rod to separate RF from the DC relay supply. --- Reg, G4FGQ |
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