Sunday, July 09, 2017

Airspy R2/Spyconverter R2: After a Few Days of Testing

Interesting days with my second mini-sized SDR! I am preparing a comprehensive evaluation, from a MW DX-ers perspective, of the Airspy. Hard-core MW DX-ers have had a preference for Perseus and RFSpace SDRs (and also the Elad FDM-S2), so there are a couple of interesting questions here: We're unfamiliar with these kind of devices, and the manufacturers and prorammers may be a bit unfamiliar with how MW DX-ers use our radios.

Some observations:

  • Its 0.5 PPM TCXO gives excellent stability when using SDR#, but SDR Console V3 (preview version) and HDSDR have some strange intermittent offsets, up to 500 Hz. Simon Brown, the owner of SDR Console is aware of the problem and I'm sure it will be addressed.
  • SDR# has limited IQ recording functionality. I hope this can be resolved, by native software or by plugin. SDR Console V3 does this very well, except a bug which is being addressed.
  • For best gain vs. protection from overloading, it's necessary to pay attention to the gain controls. I remember this being an issue also with the 12-bit Afedri SDR-net.
  • Audio quality in SDR# is very good.
  • Sensitivity isn't measured, but compared to the KiwiSDR in an A-B test on threshold signal levels. The Airspy is apparently marginally less sensitive on a MW test I did. I couldn't hear any difference when I did the same test on SW. Mind you there are many factors that determine sensitivity, not least how the AGC is used and gain settings. True DX situations late summer/early autumn will give me more answers.
  • The Airspy has a fixed 10 MHz sampling rate. Smaller bandwidths are made by decimation of the sampling rate. The more decimation (smaller bandwidth), the better performance. I'm using 2500 kHz (of which 2000 or more kHz are alias-free) for my MW tests.
  • Apparently very good sensitivity on FM. Both SDR# and SDR Console V3 have RDS decoding.
I'm looking forward to doing more work with the R2 in the weeks to come, and I hope that I can make some contributions to software and plugin programmers. There's a bit of work to be done before I would recommend the R2 for hard-core MW DX-ers. The hardware part is good though.


Luis Colunga said...

For SDR#, take a look at Vasili plugins here:

He has an IF recorder and Audio recorder you might like more.

Bjarne Mjelde said...

I know, I already have the Baseband Recorder and File Player.