[Moon-net] AC audio voltmeter via soundcard

[Leif Asbrink]

Hello Phil,

You can use Linrad for this purpose.
The Linrad S-meter can give you the averaged
RMS noise over as much time as you care to wait.

Linrad is available as an exe file at
http://www.sm5bsz.com/linuxdsp/linrad.htm

It is also available as source code for Microsoft
Windows 98,2000,XP (and perhaps others.) Download
the zip archive of Linrad source, mingw and nasm from
the above and type in one single command to generate
linrad.exe entirely from source code. It works 
under Windows, Linux and probably also free BSD.

Linrad will give highly accurate relative power 
measurements, but it will not give absolute voltages
at the soundcard input.

Beware that Linrad is a multi-purpose tool so it could
take some time to get used to it......

(To accumulate power averages, press F2. To clear
averages, press Z. Press F1 for this kind of info in Linrad)

73

Leif  /  SM5BSZ

> 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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