[TenTec] Wire loop antenna question

["Rob Atkinson, K5UJ" <k5uj@hotmail.com>]

Use parallel wire feedline, either ladder line (450 ohm a.k.a. window line) 
or better yet, open wire feed (600 ohm, available from W7FG or you can make 
it yourself which always impresses the uninitiated.."I make my own 
feedline...").  You are getting rf in the shack because your coax is 
radiating because you have a high swr on it; even worse it's also radiating 
below 7 mhz because on 80 and 160m. your antenna's resonant freq. is above 
where you are operating.  Coax is extremely lossy in these situations.  I'm 
kind of surprised you can get it to work on 160 because it is so close to 
ground and narrow (7m wide), close to ground and narrow in terms of 
wavelength on 160.  But anyway, feed it with open wire feedline to your 
house--it is low loss on any frequency you want to get on compared to coax.  
Forget the balun at the feedpoint and the ten tec transmatch because it is 
not best for balanced line.  Where feed comes in to your house, terminate it 
at a balanced feedline tuner.  Palstar makes one that I understand is very 
nice.  It is balanced because it is two parallel L networks (two rollers, 
one on each side of the line in series with the line and a capacitor across 
the line.  The balun is on the low Z side where it should be, between your 
tx and the transmatch just B4 the transmatch.  Then you can run coax from 
the tx to the tuner's balun and the tuner itself.  Now with it tuned, you 
have a nice load for your tx to work into so it's happy and almost no loss 
on the coax, and you can pretty much forget about how long the loop is and 
how long your feedline is and let the balanced transmatch take care of all 
that.  The open wire line is so low loss, length of the loop and feed won't 
matter, except maybe in an extreme case like 160 where you may have to make 
the loop longer, or you can tie the open wire feed ends together at the 
transmatch and turn it into a T Marconi.  Does all this make sense?  Write 
me if you have any questions.  I am doing this with the fishing poles too; 
mine is about 220' long and around 20 to 25' up; I run up to 1.2 kw with the 
feedpoint about 30' from shack--no rf problems (but I use a lot of ferrite 
chokes also, hi.).  Since I put this antenna up I have found I can run the 
exciter only a lot more than before.  Mine won't tune on 160 though because 
my xmatch doesn't have enough L and C.  I think the Palstar does though.
GL
Rob Atkinson
K5UJ

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