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#1
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(RHF) wrote in message om...
= = = "Pierre Vachon" wrote in message = = = ... Hi there, I am trying to build a longwire antenna for use in the 20 meter band to 70 meter band area. I was looking for advice on what materials to use for the antenna and the lead in lines. I will hook it up to a Drake r8B radio. What is the minimum height it has to be? Where to ground it?. Actually, does it have to be grounded if the radio is grounded at the outlet? A year or so ago I had to come up with a replacement for an ageing vertical antenna for my amateur radio station...After researching, I decided to put up a full wave loop cut for 80 meters..Im going to quote some sentences from this article, which you should check out: http://www.bloomington.in.us/~wh2t/loop.html "To determine the approximate length in feet of a Full Wave Loop antenna use the formula 1005/Freq in Mhz = length in feet. For 160 meters a full wave loop antenna resonant at 1.9 Mhz would be about 529 feet long. For the 75 meter band a full wave loop antenna resonant at 3.85 would be about 261 feet long. A full wave for 3.9 Mhz = 257 Feet 8 inches. " I happened to design mine for the 75/80 meter band. "This type of antenna doesn't depend on an efficient ground system for efficient performance. The impedance of a Full Wave Loop antenna is theoretically in the vicinity of 100 ohms. Connect one end of the wire to the coax center and Connect the coax shield to the other end of the wire. Be sure and seal the end of the coax against water. Form the wire in a loop and run it horizontally to trees or whatever supports are handy. Be sure to insulate the wire from the supports. " Now, this antenna works great on receive and transmit on everything from 75/80 meters and up (10-80) for transmit, the meager automatic antenna tunner in me bloody kenwood ts450sat tunes it..amazing..and the one band that sometimes gives me a bit of trouble is 15 meters, where I have to use the external tuner.. And it hears really good everywhere my radio will go (general coverage)...mine is only up an average of about 20 ft.. So, if you have the room I'd seriously consider a full wave loop..good luck.. Steve kb8viv |
#3
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Hi RHF, I used to subscribe to it but I tend to change hobbies in the Summer
LOL..Anyway, last year I remember we were trying to have a net (so to speak) on hf and it never really materialized. When summer hit I was back into my other hobby of motorcycles..I should resubscribe though, if I remember correctly there was a pretty good group there..Thanks again for the invite.. Steve kb8viv |
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