4m

The https://github.com/rxt1077/wspr_spread work is pretty awesome. It helped us debug why our TCXO-powered-WSPR beacon was pretty decent on 4m band but flaky on 2m. Doppler shift value on 70 MHz: ... 70.0924994 VU3CER MK68 23 0 0.29 1 1 0 1 44 1 810 0.517 Now see the problem on 144 MHz: ... 144.4905417 VU3CER MK68 23 -3 0.12 1 1 0 1 39 1 810 0.865 Pretty all over the place! ...

Our WSPR beacon design works fine even on the 4m band (~70 MHz) . The key is to use a 25 MHz high-quality TCXO, like the 25 MHz HCI 0.5ppm TCXO! 2m WSPR is still out of reach for now - see the following sporadic decodes. Of course, the next challenge is to get 2m WSPR beacons working 100% reliably at a low cost. ...