Topband: Evaluating Rx antennas with Spectran

[Nick Hall-Patch]

At 14:47 15/03/2006, you wrote:

>But could those BC audio frequency carriers, taken during the day on the
>ground wave, be really reliable?
>Here is my problem: I am unbable to get stable readings, as they are
>continously moving up and down on Spectran.... where am I wrong?
>(Not found enough explanations on the several Spectran settings!).
I'm sorry for the late reply, Luis, have just been checking my backlog of mail.

I don't have too much problem here with daytime signal variability on 
BC stations using Spectran (version 2, build 213).  With the Drake 
R8, I tune in LSB or USB mode to 400 Hertz away from the carrier, 
switch off AGC and leave RF gain at maximum.  If the signal is very 
strong  I adjust RF gain for a suitable level on Spectran; of course, 
it must remain at that level for other signals if one is trying to 
characterize an antenna.

In the "controls" (hit "show controls" if you haven't already done 
so), I usually use 8000Hz sampling, Avg factor of 4, and resolution 
of  .98 Hertz.   This can leave me with an audio tone that varies 
only about a decibel or so.  Is that too much variation for what you 
are trying to do?

best wishes,

Nick

VE7DXR




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Nick Hall-Patch
Victoria, B.C.
Canada

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