Satnogs with Airspy R2

Hi,

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:
https://network.satnogs.org/observations/1371007/

This is CAS-4A with RTL-SDR:
https://network.satnogs.org/observations/1353481/

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

What can be the problem with airspy?

Thanks

2 Likes

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.

2 Likes

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

73 es tu

1 Like

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? .

2 Likes

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!

Update:
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.

1 Like