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[IRCA] Fwd: [sdr-radio-com] Re: Front End Overload from AM Band using SDRPlay RSP-2



An interesting take on the latest SDRPlay radio, from the sdr-radio list. MW overload may be an issue, so be warned.

best wishes,

Nick



Gents,

I have owned the RSP2 for a week now. I've also had an RSP1 for several months. Up to this point I've been running the RSP2 on HDSDR only because SDR Console didn't support that hardware. I feed them both (RSP 1 and 2) with a full size G5RV (into either the SMA input on the RSP1 or the Hi-Z input on the RSP2). My problem is that I am bombarded by two different 50,000 watt AM broadcast stations less than 8 miles from my QTH. The RSP1 handles the situation rather admirably on all but 80 meters (that's as low in the spectrum as I'm able to go as an amateur, I don't have a 160 meter antenna) but the RSP2 is hopelessly overwhelmed across all HF bands. The MW/FM notch filter on the RSP2 has absolutely no effect against the AM broadcast band overload (although it is very effective suppression against the FM broadcast band, but that's not where my problem lies). I have ordered a Morgan Mf g. (formerly I.C.E.) M-400X AM band filter that I'm hopeful will eliminate the overload problem with the RSP2. That filter should arrive later this week.

In the meantime, I've found that I can attenuate the input signal from the G5RV sufficiently to at least suppress the severe overload condition by attaching a 30 ohm resistor across the Hi-Z input connections shared with my G5RV. It actually works quite well, dropping the received signal strength roughly 15db and bringing my RSP2 HF receive performance very close to that of my RSP1. Indeed, the Hi-Z input appears to still be amazingly sensitive in the HF bands despite the attenuation.

Just wanted to pass along what's been working for me, as far as getting past the front end AM band overload on the RSP2. I'm not sure why that unit is so much more sensitive to overload than the RSP1, except that perhaps the RSP2 is designed to be sensitive down to 1KHz signals and the RSP1 isn't advertised to be usable nearly that low.

73,

Mark  KF5VQY

Nick Hall-Patch
Victoria, BC
Canada
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