[222Activity] MSK144 vs FSK441

Keith Morehouse

The main thing FSK441 has going for it is SINGLE TONE. 

Various literature can point to some advantages and some disadvantages of each mode (MSK144 v FSK441), mostly focusing on 2-3 dB more or less sensitivity, which, IMO, is not near as important with meteor scatter as it might be with very weak constant signal terrestrial or EME work.  The bottom line, as I see it, is the ability to detect, aurally and visually, the tiny, tiny single tone artifacts in the waterfall display (and between your ears) when using FSK441.  It's been proven by countless contacts that this ability increases completion rates.

It's been suggested that a single tone isn't valid because "the operator doesn't know WHO sent that tone".  When I set up a 222 sked on a specific frequency (not on a "calling" frequency), using a long boom yagi(s) with sharp pattern, pointed at my partner station, running a specific sequence and using gear on both ends with better then average frequency accuracy and stability (most successful ops on 222 have accurate means of being "on frequency" and WSJT modes, even the old ones, give you a relatively good method of detecting how accurately you're netted to the other station)  I suspect I have a chance, very close to 100%, of knowing EXACTLY who I'm hearing.

It's also been suggested that FSK441 single-tone isn't valid because no information is passed.  I consider that to be a pretty weak argument since a multitude of operators used FSK441 daily for over a decade to make probably 10's of thousands of contacts on 6M and above and nobody has yet come forth to try and "cancel" those contacts.  Contacts can not be made invalid just because technology changes.  Furthermore, the 4-tone aspect of FSK441 single-tone DOES pass along "decodable" data, with individual messages (R26, RRR, 73, ect) corresponding to individual tones (frequencies) that are easily recognized when stations are closely netted in frequency.

I strongly advocate the continued use of FSK441, outdated as it is, on 222 meteor scatter.


Keith J Morehouse
Managing Partner
Calmesa Partners G.P.
Olathe, CO

On Sun, Nov 15, 2020 at 8:09 AM James Duffey <JamesDuffey@...> wrote:
If you are interested in a quantitative comparison of the two modes, WB2FKO’s paper comparing MSK144 with FSK441, referenced in K5ND’s web article, is an enlightening read and well worth the time spent with it:

 Unfortunately, due to the pandemic shutting down the VHF society meetings, this nice bit of analysis has not received the widespread distribution it deserves. - Duffey

James Duffey KK6MC
Cedar Crest NM