Re: RF Gain & NR w/ RSPDuo


jdow
 

I see a little bit of a problem here. On 40 meters the RF Gain control cannot change the actual SNR due to all or most of it coming in on the antenna wire. And as a practical matter I've seen a front end that actually developed a lower noise figure with increased AGC action It had other defects that made it undesireable. So I am not sure what effect you are experiencing on your transceiver.

That said on the left you will see an AGC tab. Click to expand it. Then click the off button. The "Gain" slider then behaves like an RF gain control. But it will behave the same as the audio level control for SSB and CW. For AM you may see a difference. I suspect it will not be big. Note that an SSB or CW receiver without AGC is basically a direct frequency conversion to audio frequency from RF with filters and no other audio conditioning. So going from maximum gain downwards can only increase the noise level relative to the signal level.

In general you get the best SDR or ham transceiver performance with the gain set at the point the signal to noise stops improving with increased gain. You can increase the gain usefully until you see spurious signals more or less explode onto your spectrum display. You cannot do better usefully.

{^_^}

On 20210722 09:28:06, n6vl via groups.io wrote:
Using a new RSPDuo with V3 and having trouble with RF Gain and Noise Reduction. I've been listening to SSB and CW signals on 40 meters and trying new emulate my ham HF transceiver. I'm used to lowering RF Gain to get a better signal to noise ratio. Also the same with Noise Reduction.
But this isn't happening with SDR Console V3 for me. I have a little better success with SDRUno with noise reduction. But I like Console so much better, especially for an ergo perspective. Bottom line: I get fatigued trying to copy signals with my RSPDuo.
Any ideas? de Steve N6VL

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