What I saw as a "sine" envelope is apparently normal for PSK, and probably not
some kind of ground problem. See waveform descriptions at:
http://www.ssiserver.com/info/pskmeter/pacificon2002.pdf or
http://www.rcarc.org/presentations/PSK31.pdf
But the fact that it does have a varying envelope could account for the lower
average power readings.
Waveform shaping is used to soften "key clicks" caused by sudden phase
reversals. "In PSK31, a cosine shape is used. To see what this does to the
waveform and the spectrum, consider transmitting a sequence of continuous
polarity-reversals at 31 baud. With cosine shaping, the envelope ends up
looking like full-wave rectified 31Hz AC."
http://bipt106.bi.ehu.es/psk31theory.html
This is a learning process so I am hoping this is nothing more than an operator
problem, most likely it is. Thanks for the interest, but you may be hearing
more. ;-)
Jim N4BE
---- Ron Castro <ronc@sonic.net> wrote:
> That is beginning to make more sense, although the sine modulation may
> indicate there is a hum problem lurking somewhere! If you can't push the O2
> into ALC range, the output from the Navigator is too low. Even if you don't
> want to run ALC in normal operation, there should be enough input to drive
> it there when everything is 'maxed out'.
>
> Ron Castro
> Chief Technical Officer
> Results Radio, LLC
> N6IE
> www.N6IE.com
>
> ----- Original Message -----
> From: <jmiller1706@cfl.rr.com>
> To: "Ron Castro" <ronc@sonic.net>; "Discussion of Ten-Tec Equipment"
> <tentec@contesting.com>
> Sent: Wednesday, February 11, 2009 12:49 PM
> Subject: Re: [TenTec] O2 output level with PSK aux
>
>
> > Thanks to all for the suggestions. On RTTY AFSK (basically a constant
> > carrier)I do get about 80-90 watts out on second measurement, with
> > Navigator set to max outputs. The Navigator still seems to be a bit light
> > on drive for an Orion however. Now, looking at PSK on a scope, I see that
> > it is not exactly constant amplitude when idling, as I had assumed
> > erroneously previously - seems to have a slow sine modulation envelope on
> > it. I assume that's normal (?). This could account for the lower
> > average power reading on the wattmeter in that mode. When I set the
> > wattmeter to peak/hold, it shows close to 90 watts (by capturing the
> > peak). Of course that's too much, but I think that explains some of the
> > discrepancies.
> > N4BE
> >
> >
>
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