August 17th 12, 01:56 PM
posted to rec.radio.amateur.antenna
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First recorded activity by RadioBanter: Jan 2012
Posts: 26
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DSP software for using sound card audio strength to compareantennas?
On Thu, 16 Aug 2012 09:25:12 -0700, TF3KX wrote:
Hi everyone:
I am about to compare the performance of two HF antennas and have an
idea for doing this, that I would appreciate comments on.
The objective is to determine which antenna yields a stronger signal to
DX locations, and even get a measure of the difference in dB. I am
assuming that the antennas are reciprocal, so if antenna A receives an
X-dB stronger signal than antenna B, antenna A will also yield an X-dB
stronger signal from my transmitter to that location. So, I would like
to measure the signal strengths received through these antennas and
compare them. For this I would listen for CW or digital mode signals,
switch back and forth between antennas, turn off the AGC and record the
audio into a file (or monitor it directly), where I could accurately
estimate the signal strengths and compare. I realize that different
noise levels, fading, intermittent signal transmission, etc. will affect
the absolute signal levels, so the software should be able to handle
this. For example, by measuring the signal carrier alone and/or SNR. And
it would be nice if the software could give me an "envelope reading" of
the signal, for example, to estimate the CW signal.
Do any of you have comments on this methodology to compare antenna
performance? And do you know of any DSP / sound card software that
could be used for this?
73 - Kristinn, TF3KX
http://w5big.com/spectrogram.htm
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