Setting up a bank of WSPR skimmers
A couple of months ago I bought a KiwiSDR + BBG and, among other tests, tried running multiple instances of its WSPR extension. I was struck by the fact that its sensitivity appeared significantly better across the MF/HF bands compared to a Red Pitaya SDR122.88-16 with sdr_transceiver_wspr software that I’d been using as a WSPR skimmer for the previous three years. With the KiwiSDR and Red Pitaya sharing the same broadband vertical antenna through a high-quality skimmer, spots from the KiwiSDR showed SNR typically nearly 10 dB stronger.
After buying a second KiwiSDR + BBG, I’ve been experimenting with using them together as WSPR skimmers covering eight bands. For now I’ve tried using a Windows 10 PC with Firefox browser and eight pages open covering the receivers on the two KiwiSDR’s. This worked well, except that it caused the power supply I was using for the KiwiSDR's to run really hot (a replacement is due shortly).
If I stick with using the two KiwiSDR’s for WSPR skimming, I’m wondering about some questions:
1) I’d like to go with a lighter-weight device to run the web client, instead of the Win 10 box. One option would be a Raspberry Pi 3B+ or 4B with Raspbian. Do one of these seem like it would be up to running the eight web browser instances? I assume that waterfall displays should be disabled to keep down the processing burden on both the KiwiSDR’s and the R Pi.
2) Is there any other way to do the WSPR instances besides use of a running web client as noted above? In case of a power loss, it would be great if all the pieces could auto-boot and restart skimming. Is this possible, or would I always be looking at manual config for each band after the components are restarted?
3) I was thinking about mounting the two KiwiSDR’s together in a shared metal case, with a quiet fan sized to cool both of them. Apart from thermal considerations, are there any reasons (RF issues?) to avoid that?
4) Are there any reasons to enable GPS if the KiwiSDR's are devoted only to WSPR? Or do they default to getting sufficient clock accuracy through, say, internet ntp?
Thanks for any possible thoughts.