Nooelec NESDR Smart XDR and IF gain settings in SatNOGS

Hi all,

In attempts to tweak the IF Gain (6 total) on a Nooelec NESDR Smart XTR, I’ve read the SatNOGS SDR setup guide and associated manufacturer data sheet.

The SatNOGS SDR setup guide offers this starting point for a E4000-based SDR such as the Nooelec:

  • SATNOGS_GAIN_MODE="Settings Field"*
  • SATNOGS_OTHER_SETTINGS=“IF1=6,IF2=3,IF2=2,IF3=0,IF4=0,IF5=2,IF6=3,TUNER=30”`*

This works without any modifications and yields decent observation results in terms of both the waterfall and generation of data frames for most satellites when compared to a RTL-SDR v3 blog that was in place for months prior to the Nooelec SMArt.

Why are there two IF2 parameters listed in the SatNOGS example, is it a typo? The Nooelec spec sheet show the possible setting for IF2 as 0,3,6,9 (not 2)

I’ve also tried changing the parameters to all 6 IF settings but do not see any difference but will keep messing with these.

I have noticed some satellites signals are now very weak and I can barely decode any frames from them any longer (FALCONSAT-3, BOBCAT-1 and RAMSAT-1 for example) when compared to using a RTL-SDR v3 blog for months with the same system and decoding tons of frames in single passes. Hence why I am trying to tweak the Nooelec IF gain settings.

Any insights would be greatly appreciated. Thanks.


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I think I wrote that, and it’s possibly a typo on my part.
Look into the SoapyRTLSDR code, it looks like it’ll just pick the nearest valid gain setting to the user-provided setting:

As for optimizing the E4000 gains… that’s a complex problem. I suspect you would be best off radiating a weak signal somewhere in the vicinity of your receive system, and tweaking the gains to adjust for best SNR, while also avoiding IMD products.


Great, thank you for this, much appreciated. That helps a lot.


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