SDRPlay overload "issue" on FM band
Posted: Sat Mar 07, 2015 7:30 pm
For info:
Beaming west - which is unusual - I've suceeded in overloading the SDR and generating inter-modulation products out of band. A number of input signals would have been above 70 dB and my set up includes a 20+dB preamp which is probably delivering 16dB extra after signal splitting. AGC was on. The problem was overcome simply by reducing the LNA GR to ensure the LNA did not kick in. Careful checking showed no reduction in s/n ratio on weak signals (because of the external preamp).
So - don't panic - but something to bear in mind to ensure best performance under different circumstances.
Rgds
David
Beaming west - which is unusual - I've suceeded in overloading the SDR and generating inter-modulation products out of band. A number of input signals would have been above 70 dB and my set up includes a 20+dB preamp which is probably delivering 16dB extra after signal splitting. AGC was on. The problem was overcome simply by reducing the LNA GR to ensure the LNA did not kick in. Careful checking showed no reduction in s/n ratio on weak signals (because of the external preamp).
So - don't panic - but something to bear in mind to ensure best performance under different circumstances.
Rgds
David