[Moon-net] AC audio voltmeter via soundcard

[Rex Moncur]

Hi Phil

FSM (Field Strength Measurement) by Owen Duffy, VK1OD, should do what you
want at:

http://www.vk1od.net/fsm/

You can set the samples up to 256 which produces an average of around 20
seconds and is great for sun noise measurements. You can also set it to
wider than SSB passband, if you have it, to get an improved average. It has
a resolution of 0.1 dB and measures true RMS.

It is still best to use it as a reference for a Y factor measurement with a
good attenuator to avoid any non-linearties in your system. But if your
attenuator has only 1 dB steps you can measure any non-linearity and correct
for it to get better accuracy.

73 Rex VK7MO


Hi All,

I wonder if there is a win freeware program using soundcard that can tell me
the 
value of the audio voltage at the input of the sound card, via mic or line 
input. If it could average the data it would be fine also. I would like to
use 
it for sun noise measurement and other source also, to get a good reading on
my 
antenna gain.
Via my voltmeter is not that good.
I have found some spectrum analyser and oscilloscope software but none can
give 
me this value.
Tks in advance.
I will send my results on 70cms asap. 26 qsos and found cdx not that good...

Vy73 - Phil - FR5DN


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