Hello Andy,

as John wrote:

> MSK is available in Spectrum Lab, and we have used it a little over here 
> on 137. Wolf's implementation is based on the PSK31 varicode. The mode 
> does work, but seems to be a bit "deaf" compared to PSK. As I recall 
> (it's been a while), Wolf indicated that the decoder could stand some 
> improvement.
> 

Confirm, and not much to add here. The decoder works to some extent, but 
definitely needs improvement.
I gave up on improving it at that time, since there seemed to be little 
interest in it.
If I remember correctly, there was some successful  2-way MSK contacts within 
DL, and a few SWL reports, but that's about it.

I never got the Massey-Hodgart decoder running properly (it always got stuck in 
some state), so we just used the simple incoherent detector with a matched 
filter.  I still have the C / C++ sources here, so anyone is invited to improve 
it ;-)

Cheers, 
  Wolf  DL4YHF .

P.S: Thanks for the LF QSO Jim, pushing the score to four CW QSOs on one 
afternoon (PA0SE, DL2HRE, G3YXM, M0BMU). 
Now closing on LF due to increased QRN .