WSPR Decoding Challenges

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!

A better WSPR generator would produce something like this:

…

We will get there at a low cost eventually ;)

References:

• https://github.com/rxt1077/wspr_spread

• https://github.com/kholia/Easy-Beacons-STEM

• https://github.com/kholia/Si5351-Module-Clone-TCXO/tree/master/Si5351-Trimmed-Module-25-MHz