Re: SW2 S-Meter #fdm-sw2 #fdm-s2 #smeter

Neil Smith G4DBN

I find the markers in the IF window more useful than those in the main window. If you set the averaging in the IF window to 60 or 100, then the numbers are smooth enough to use for sun noise measurements on microwave bands.  You can reduce the jumpiness of the on-screen measurements by changing the averaging on the main waterfall to 20 or so, and smooth out the S meter readings by changing the update interval from the default 60 ms, but I don't know if that does an averaging process, or just discards the intervening measurements!

For anything really clever, it is probably easier to work on the waterfall data which is streamed out of the extio port, and do the analysis using some custom code.

Neil G4DBN

On 19/03/2020 10:01, Paul White wrote:
Ivo's post prompts me to air my own comment on the SW2 S-meter.
I'm not an expert user. There are two radio/software combinations available to me whose S-meter by reputation provides a well-defined, accurate and reliable total (not peak) power measurement: RSP1A+SDRuno and S2+SW2.
My use of S-meter readings includes:
(a) meaningful logging of received signal strength, for signals of any type
(b) comparative assessment of changes to system components (e.g. antenna mods)
I have no specialised signal measurement equipment, hence the reliance in (b).
In those activities (for my comfort) there are two enhancements to SW2 that could help considerably:
(1) showing Marker 1-type data in the "desert" next to the S-meter
(2) calculating/displaying an average S-meter reading as well as SNR
The argument for (1) is that bringing up marker data is time-consuming. For (2) it is that even relatively stable signals show fluctuations that cannot accurately be averaged by eye.
Refinements could be:
(3) user control over averaging period
(4) calculating/displaying the S-meter variance (standard deviation)
I would find (3) especially useful for slow fading, and (4) as a measure of fading severity.

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