Satnogs with Airspy R2


After trying SatNogs with my RTL-SDR V3, I decided to go with an Aitspy R2 due to the better SNR. What I am experiencing is something weird. CAS-4A CW telemetry is a fair copy on my RTL-SDR but all I can receive with the Airspy is a weird signal that seems more some kind of FSK transmission.

Here’s the reception of CAS-4A with the Airspy:

This is CAS-4A with RTL-SDR:

Of course I am using the same antenna and Rspberry Pi.

What can be the problem with airspy?



The Airspy uses the host CPU to convert the samples into quadrature I/Q data and this process requires a significant amount of CPU power. A Raspberry Pi 3 might work at 2.5 MSps but not at 10 Msps (it can’t even do USB transfer at that rate). A Raspberry Pi 4 or an SBC with Intel CPU has better chances.


Many thanks Alexandru. I will try the Raspberry Pi4 and see how it handles CPU conversion.

73 es tu

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I’m trying to get my new Pi4 and AirSpy R2 working together. The updated Ansible client has new fields and I’ve entered the same values I’ve been using with SDR#, but some are unfamiliar. Here’s a screen capture of what I have so far. Any suggestions? .


What error do you get, if any?

I didn’t see any errors. I did change the receiver to “airspy” instead of “airspy/airspymini” and started seeing some satellites, but very few decodes. Have removed my custom values for the gain, bandwidth, and sample_rate and will try with just default values.

Using rx_device “airspy” with no custom receiver settings didn’t work. Nothing uploaded. Will try RX_SAMP_RATE at 2.5e6 again but with no other custom settings.

Passes still failing with RX_SAMP_RATE at 2.5e6. Running out of ideas!

Finally getting some waterfalls after I corrected the SatNOGS URL to https instead of http! But with the AirSpy R2 using SatNOGS defaults I’m not getting decodes but do see a good signal on the waterfall at least.

Using SDR# with my old AirSpy R1 teed to the same antenna I decoded 27 packets from Bugsat-1 but nothing decoded with the Pi4 and AirSpy R2. So, something’s not set right in my configuration.

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