[CQ-Contest] Splatter and poor modulation

Rick Kiessig kiessig at gmail.com
Wed Oct 10 19:33:34 EDT 2012

I've been using an SDR for about 6 months now, including observing up to 400
Khz at a time during a number of SSB and RTTY contests. I'm using a NetSDR
with an FTdx-5000 and the SDR-Radio software.


One thing I've noticed when the bands are busy is that there are often quite
a few SSB signals with splatter so bad that instead of occupying the usual
2.7 KHz or so, they use three times that much bandwidth. Of course, you can
hear the splatter without an SDR, but the waterfall display makes the cause
(and extent) obvious. Such stations are relatively easy to avoid in
day-to-day operations, but in contests they can be very annoying; if a
high-splatter station starts to call CQ 3 or 4 KHz away from my run
frequency, it eventually forces me to QSY.


I've also noticed a number of stations with modulation so poor that they are
very hard to understand for a brief contest-type QSO, and close to
impossible to work for any length of time.


I realize that neither of these problems are anything new, but I was
thinking that providing SDR recordings of such signals to the operators
might help them understand the problems they're causing and perhaps motivate
them to clean up their act.


I know if my signal was causing splatter or was poorly modulated, I would
definitely appreciate someone letting me know. I thought about creating a
website to host SDR recordings, but for the moment I'm planning to just
upload them to someplace like Dropbox, and email hams directly with a link,
provided I can find their contact details. Eventually, it might be
interesting / useful to provide recordings on request as well.


Has anyone tried something like this before?


If you have an interest in collaborating along these lines somehow, please
let me know.


73, Rick ZL2HAM (ZM1G)


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