Comparing SDRs

This is purely subjective post describing my experience with various SDRs which some may find a little useful.

The UK powers that be still think that pagers with a million times more power than our weak sat signals should be allowed to operate on the top end of the VHF satellite band. Pagers overload most receivers so you need to find devious methods to over some the problem.

I've used many Software Defined Radios and primarily for weather sat reception. In no particular order I'd describe them as follows:


Generic RTL2132 based USB sticks
Very good for general VHF work with NOAA and Meteor sats as long as you don't live in the UK (pager problems). Cheap, so a good choice for starting before committing to this as a hobby. Easy to set up (using Zadig - just follow the online instructions). Works with most SDR software as well as with rx_fm if you want to automate reception using linux.

SDRPlay 1
Better quality reception than the RTL2132 sticks but a little more complicated to set up. Software is limited to a handful of apps such as  SDRUno or HDSDR although more can be made to work through the use of the EXTIO driver. Much more expensive than the RTL2132s.

SDRPlay 1A
More sensitive than the SDRPlay 1 but the same software limitations apply. Both are susceptible to pagers if those are strong in your area.

SDR v3
A better quality RTL stick than the originals. Less susceptible to pagers and an overall better experience. Reasonable cost.

AirSpy HF+ Discovery
This was purchased solely to resolve the pager problem once and for all. This device (like most Airspys) is not RTL based so can mostly be used with AirSpy's excellent SDR# software. Although older SDR# versions can run under wine the experience of controlling in on linux is patchy so we're really looking at SDR# on Windows. Similar cost to the SDRPlays.

I use a small preamp at the antenna with 25m of RG58 coax to the radio.The preamp increases signal by about 20db which causes pagers to overload the receiver regardless of which of the above I use. The answer would be to put a longer coax section in or add a 3-10db pad to reduce signal strength, or move the receiver to the antenna and dispense with the preamp altogether. I'm getting good pager-free results without a preamp by using the AirSpy connected to a Raspberry Pi running Airspy's SpyServer software at the antenna and connecting to it from SDR# some distance away. The Airspy has good inherent rejection of adjacent signals compared to the RTL2132s (IMHO better than the SDRPlays) so in this configuration, that, and it's amazing detection of weak signals makes it my favourite.