On Jan 16, 2011, at 10:21 AM, Ktfrog007@aol.com wrote:
> For rag chewing, which is mostly on PSK, I run 30-40W.
Remember that PSK31 works under a different "rule."
PSK31 is, through the genius of Peter G3PLX, not simply PSK modulation but also
is amplitude waveshaped. If not for the amplitude waveshaping, PSK will have
the same wide keying sidebands that you see on FSK signals.
Instead, when you look at an idle PSK signal, all you see are just two
carriers, 31.25 Hz from one another (unless the transmitter has poor IMD, when
you will see more keying components).
However, this waveshaping also creates a crest factor of 3 dB. If your
transmitter clips at 100 watts, you should not set the average RF power, under
the idle PSK31 modulation, to any greater than 50 watts.
This peak power to average power ratio is not such a big deal to hams. But to
professionals, crest factor matter since peak transmit power is sometimes a
constraint in the design. Because of that, PSK31 is probably not as useful to
them, but the waveshaping of PSK31 a going to be a godsend when the sunspots
come back again to face many more digital mode stations.
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