[Fourlanders] MSK144 and Power

[Jim Worsham]

I had that happen to me also.  Apparently if someone calls CQ and they aren’t in the log it just assumes you want to work them, tunes the radio to their frequency and runs with them.  Surprised the crap out of me the first time it did that with.  Joe and his team are really pushing the edge of the possible now.  We aren’t in Kansas anymore guys.  Lots of new stuff for all of us to learn.

73
Jim, W4KXY

Sent from Mail for Windows 10

From: John Kludt
Sent: Wednesday, January 31, 2018 4:44 PM
To: Fourlanders
Subject: [Fourlanders] MSK144 and Power

All,

We did have some questions on MSK144 during the contest.  With all of the talk about distortion on FT8 I wondered if MSK144 had the same potential issues.  I asked the question and got the answer, "Na, meteor scatter is meteor scatter and you should run as much power as you can."  This was from one of the development group and is not an unexpected answer. He went on to say that the pings are rather distorted anyway and MSK144 seems to be very robust in figuring things out.  We still need to generate a clean signal but just as with FSK441 meteor scatter is meteor scatter

A couple of other questions were also resolved.  On some the reflectors it was noted that the "problem" with MSK144 was only one station could be on frequency at a time.  Not true.  Pings are frequently microseconds in duration.  hence, using natures algorithm we are using time domain multiplexing to get multiple signals on the same frequency.  Indeed , watching the decode screen multiple calls would appear in the same 15 second sequence.

The price for this is paid in the computer.  All of the other WSJT-X modes wait till the end of the sequence to decode.  MSK144 decodes real-time as the signal arrives.  And that takes a fair amount of horsepower.  The normally  green bar  on the lower left hand corner of the screen turns red and shows % use of the decoder at >90% and things pretty much stop until the decoder catches up.  Lesson learned, MSK144 takes a fair amount of computing power to succeed.  Not sure as to the minimum but it is probably in the range of an i5 or equivalent and 8Gigs of RAM.

One other things, just because it was the first time I had actually seen it happen:  K1JT calls "CQ 280 K1JT"  meaning Joe is looking for a contact on 50.280 (we were on 50.260).  I grabbed for the tuning knob only to realize through the magic of CAT Control the radio was already on 50.280 MHz.  Really cool stuff!

So, the digital revolution continues with new things to learn and new opportunities for weak signal work on an otherwise "dead" band.

Johnny, K4SQC
6m Band Captain

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