Part of the reason for running low power with PSK is that when you are in
receive, you are listening to 2KHz of the band and a strong signal will wipe
out the whole 2KHz.
Another reason for reducing the power output is PSK requires linear (class
A) operation because the signal is phase shifting and most transmitters run
class AB at full output, which is 'almost' linear.
Most 'linear' amplifiers are not true linear - they run class AB or in some
cases (cw and fm) class C.
de Paul, W8AEF
ZF2JI/ZF2TA FO8DX/FO8PLA 8Q7AA XZ0A VU7RG/VU3PYM TX5C A52PP
> -----Original Message-----
> From: Amps [mailto:amps-bounces@contesting.com] On Behalf Of Jerry Kaidor
> Sent: Sunday, September 30, 2012 8:49 AM
> To: Allen Brier N5XZ
> Cc: amps@contesting.com
> Subject: Re: [Amps] Alpha 78 in Digital Modes
>
> I actually bought my Alpha 78 because of digital modes. My 30L-1 just
> wouldn't handle them. I got a little flak on Eham because I mentioned it
> - people were telling me - you shouldn't be running more than 20 or 30W on
> PSK. Personally, I thought they were full of it. PSK seems to work just
> like other modes - people don't hear you, you press the big switch and
> then they do hear you. It's not WSPR. Somewhere I read a comparison of
> low-signal performance of digital modes, and PSK was about as good as
> RTTY.
>
> Still, everybody I QSO says - 20 or 30 Watts. I wonder how many of'em
> are lying? :).
>
> I am careful to keep things linear - I turn the power down on my
> TS590S,
> make sure there's no ALC showing, and verify that the crossovers on the
> PSK waveform are nice and clean on my monitor scope.
>
> - Jerry Kaidor, KF6VB
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