TF3KX wrote in news:d5179c14-5fa8-4ca4-aaf3-
:

Is there any software available for measuring S/N and signal strength,
through the soundcard? My idea is to analyze signals arriving from my
antenna, through the receiver and the soundcard, and thus compare
antennas numerically in terms of signal strength and noise.

This capability is already present for the most part in the Faros
beacon monitoring software, but it is tailored to monitoring only the
IARU/NCDXF beacon signals.

73 - Kristinn, TF3KX

You haven't mentioned the frequency at which you want to make the
measurements. Techniques vary with frequency, and the significance /
nature of some noise sources is also frequency dependent.

Measuring S/N ratio is somewhat easier than measuring signal strength.

Nevertheless, there are ways to measure absolute field strength. FSM
(http://www.vk1od.net/fsm/) provides a method that uses a known antenna
and known receiver to measure field strength in absolute units. Along the
way, it calculates receiver input power which might be of interest.

NFM (http://www.vk1od.net/nfm/) was specifically written for noise figure
measurement using the Y factor method.

Spectran might well provide a first up simple solution to your needs,
here is a note on using Spectran for assessment of weak signals:
http://www.vk1od.net/gt/nfisa.htm . Keep in mind that S/N ratio is key to
copying another station, but the N term includes your noise environment
which may vary from one antenna to another. Improving the N term does not
often significantly improve your EIRP which contributes to the S term at
the other end of the link (assuming two way communications).

Here is an application of NFM to plot the pattern of a 1296MHz dish using
sun noise:
http://www.vk1od.net/nfm/application...ernFromSun.htm .

Owen

Owen Duffy wrote in
:

Here is an application of NFM to plot the pattern of a 1296MHz dish
using sun noise:
http://www.vk1od.net/nfm/application...ernFromSun.htm .

Correction, it is actually a plot of the pattern at 2304MHz.

Owen