[Antennas] Antennas Digest, Vol 86, Issue 1

Wed Mar 2 08:38:47 EST 2011

Henry oz3o n2nr Mei'l's wrote:
> I experienced that immediately after (April!) rains showers, I could work
> Florida and other Southern states on 40 meters AM from NYC, in mid
> afternoon, running about 70 Watts -- the antenna was a 1/4 vertical using a
> wire mesh fence as ground counterpoise.
> I could not do this in dry weather. Sunspot activity was also very favorable
> in the late 50's.

 Much more counterpoise (tuned as in 1/4 wl) and you can enjoy that 
performance year round and more.
> Since the theoretical impedance of an ideal GP is 35 ohms, what about using
> two parallel 70 ohm
> cables? But I suppose 50 ohms approaches the actual impedance of non-ideal
> GP's. By adjusting the angle of the radials
> with respect to the horizontal, 50 ohms can be achieved, assuming your feed
> point height and physical environment makes this a practical possibility --
> not often the case on the lower bands.

 Two 75 Ohm cables (the exact same length) in parallel is perfect and 
has been used for at least 50 years. (RG-59, RG-11 or cable company wire)
-- 
 Ron KA4INM - Endless Loop: n. see Loop, Endless.
 Loop, Endless: n. see Endless Loop.
 -- Random Shack Data Processing Dictionary