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Worse reception with SDR console 2274

Posted: Thu Oct 22, 2015 1:53 pm
by zanco
Hi, I also posted this on facebook:

SDRPlay and SDRConsole build 2274 question.
Hi, I installed the newer build 2274, running Win10 on an I7 with 16 GB ram. I do notice that the stop start when switching bands in not longer necessary and that's great news. I do however have a problem with the gain (settings). Some of the gain reduction settings (10 dB, 15 dB) remove the signal completely, where 20 dB or 5 dB shows the signal again. The visual gain has influence on the signal strenght. If I change the visual game, which I assume has only to add to the signal that it's high enough to show in the waterfall, then the S meter readout lowers for the same amount. So, visual gain from 25 to 0 "costs me" 4 S point on the S meter,
I also notice a big lot of loss in the USH 401 - 406 MHz band. With the Airspy and the SDR Play connected to the same antenna, where the SDR play is bandpass filtered and pre-amped at 403 MHz the Airspy gives me a solid S9 (without preamp) and the SDR play gives me S6. If I exchange the receivers and have the Airspy connected to the preamp output the signal rises from S9 to S9 + 10 and the SDR play without preamp drops about S3. Does anyone else have this experience ?
I have switched to HDSDR for a moment and with the SDR play and preamp the signal is now S9 +30 (Logper pointed at a radiosonde at 15 km height and 100 km away)
Kind regards,
Ben - PE2BZ

Re: Worse reception with SDR console 2274

Posted: Sat Oct 24, 2015 6:50 am
by jon
S-meter readings are tricky with SDRs - since they try to mimic something designed for analogue receivers which measured AGC voltage in a very narrow bandwidth. Hence why there are calibration settings to allow users to get close to something familiar in any particular way of working - this WIKI may be helpful where it talks about Accuracy and SDRs : https://en.wikipedia.org/wiki/S_meter

In SDR-Console, 'visual gain' is effectively the way you calibrate the S-meter.

In HDSDR, click Options -> Misc Options -> S Meter calibration.
• You will be presented with a dialog box which outlines the instructions
• Once you click OK you will see the S meter now read S – Units calibration
• By left clicking you can set the meter to the known reference.
• One you are happy right click to finish the calibration.