Re: SDR Radio S/N measurement


That does not tell me your circumstances, only your use. While it helps a litle (rules out Radio Astronomy tweaks) it still does not suggest what is best for you. Presuming you are passing rational (are using the RTL dongle for 50 MHz and higher) then your circumstances of interest are local noise levels and whether or not you have local high power signals to contend with within 10 MHz or so of the frequencies you find interesting. I have published for some time now a source dll for SDRC using RTL dongles. It features three different gain setting modes that set all levels at the same time. One is little or no compromise for sensitivity, one is major compromise to improve dynamic range, and one is a reasonable compromise between the two. It does not feature three individual gain settings as it's too easy to find yourself off in the woods lost and alone.

The BASIC method for setting the gain control is fairly simple. Set the gain to about 10 dB give or take whatever. Find a signal that sticks up about 20 dB above the noise fuzz. Increase the gain step by step until you hit an increase that causes the signal and noise to increase about the same. That is maximum practical sensitivity without severely compromising dynamic range on the very limited dynamic range of the RTL dongles. If there is a lot of high power stations you may have to compromise sensitivity by dropping the gain a step or two.

You can grab "SDRSourceRTL2832Y Distribution". And if you are into sharing sets of favorites the "Merge SDRC Favorites" tool can be useful. (Thanks to Leon Koning who helped debug it.

My WorldShare folder,, also has some useful files (and some cat pictures.)

{^_-} Joanne

On 20190623 01:56:18, Chris van Lint wrote:
Thanks Claudio.
As I mentioned at this stage I am only interested in BPSK.  I could use the "other" software to determine the most suitable gain setting, but because I run 18 VFOs it is not really suitable for general use.  I am a SDR Radio fan and I'll wait until Simon and of course his dog are ready, even though I realise I am at the back of the queue.
At 06:06 PM 23/06/2019, you wrote:
Hello Chris .

/"What I want to do is find the best gain setting for the humble RTL2836, in my specific circumstances"

/In this case the tool of SDR# is useful for this purpose , while I don't know if for all kind of modulations , especially for FM , like in other discussions .

Please consider to install the plug I suggested you that look to give  you a continuous value of quality of what you are demodulating inside the RF BW window on a virtual analog meter representation .

Have fun with you hobby !

73 - Claudio Re I1RFQ

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