[Hallicrafters] Re: Hallicrafters Digest, Vol 9, Issue 26 (Dummy Antenna)

[Edward B Richards]

Hi all;

Re this thread on dummy antennas, I have some questions. I think most of
us use a 50 ohm coax cable to our receiver. In that event, what is the
advantage of aligning a receiver for peak performance at 300 -400 ohms
antenna Z ? It seems to me that the antenna Z only affects the antenna
tuned circuits. I would think that the isolation provided by the RF amp
would preclude it affecting anything down the line. In that case, why not
align the antenna circuits to the 50 ohm Z of the sig gen. I always peak
up the ant circuit on the antenna after alignment anyway. I think it was
Glen Zook that recommends using a TV balun to match the coax to the
300-400 ohm antenna input. In this event I would tune the antenna
circuits with the balun between the sig gen and the receiver. I would
re-peak them to the actual antenna being used after all else is done. Any
comments ? Thanks.

73, Ed Richards K6UUZ


On Tue, 26 Oct 2004 09:15:17 -0400 "David C. Hallam"
<dhallam at rapidsys.com> writes:
> Just for everyone's information in case you don't know;  The RMA 
> dummy
> antenna described by Jim is the same as the SM-35/URM-25 antenna 
> simulator
> as furnished with the URM-25D signal generator.
> 
> 73
> David C. Hallam
> KC2JD