[Antennas] Appropos the care and feeding of GP'S

Wed Mar 2 03:33:42 EST 2011

I suppose a 2:1 balun between an 72 ohm line and a GP would be less 
cumbersome than two parallel
72 ohm lines, though 2 cables/lines would also reduce RF loss.
Is it all possible to design baluns with fractional ratios, e.g. 1.5:1 for 
35 to 50 ohm matches?
I don't mean RF transformers/tapped inductors, here: they would have 
narrow/single-band frequency applicability.
Unless, of course, you have a monoband GP; that could also be done with a 
capacitive divider.
Henry oz3o n2nr
----- Original Message ----- 
From: "Henry Mei'l's" <meils at get2net.dk>
To: <antennas at mailman.qth.net>
Sent: Wednesday, March 02, 2011 6:43 AM
Subject: Re: Antennas Digest, Vol 86, Issue 1
>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.
>> 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.
>> Henry oz3o n2nr