[Antennas] long wire antenna - can you use coax to get outside house?

2002年5月16日 22:18:40 -0400

At 09:39 PM 5/16/2002 -0400, Joe Falcone wrote:
>I was wondering if you guys could give me your thoughts on the following:
>>I want to run a long wire direct from the tuner. I also wanted to run a 
>counterpoise from the tuner. Would it be a bad idea to run them together 
>until I got out of the house? Would I be better off to use coax, to get 
>out of the house, and just use the center conductor as part of the long 
>wire? Could I then run the counterpoise next to it? If I did that, do I 
>count the coax as part of the length of the wire?
>>Or should I use the shield of the coax as part of the counterpoise until I 
>got out of the house. The coax would be about 15 feet.
>>Thanks Joe,

You can use a coax and it changes the impedance of the antenna system at 
the feed point, but really is not part of the antenna or the 
counterpoise. I have a W3EDP antenna which is an 85' wire and a 17' 
counterpoise and at first I brought both into the shack to a manual 
tuner. Then I got an automatic tuner and ran a coax outside where I 
installed a 4:1 balun. The efficiency of the balun is good, but I lose a 
little power in it. It gets slightly warm at 100 watts. I also lose a 
little in the coax. I have a coax switch and switch from my K2 which has 
about 45' coax or to my Omni-VI with a Z11 tuner which has about 20' 
coax. I can tune both rigs up fine, but the tuning is a little different 
because the coax changes the impedance along its length.
GL
73, Chas, W1CG