On Sun, 2007-07-15 at 08:08 -0400, Bwana Bob wrote:
> Yes, I thought about that, but I haven't done the math. Actually, the
> Scout has a 2.5 MHz PTO, but the second harmonic may cause trouble,
> although there is a low pass filter on the PTO output.
>
> 73,
>
> Bob WB2VUF
Double balanced mixers produce more output power from the second
harmonic of the drive than they do mixed output from fLO +/- fIN. Even
with a pure sine wave LO drive. Other mixers are generally less clean.
So the PTO tunes 2.5 to 3? second harmonic then tunes 5 to 6? kind of
makes that range a no go region because of transmitter spurs.
Getting on 60 meters might be better using a 28 MHz output and mixing it
in a transverter so the PTO spurs would be well filtered, but then the
PTO second harmonic will still likely be heard on receive at some
frequency, strong, and the bother of a transverter is a lot for 5
channels. Otherwise the 50 watt rating of the Scout is handy to match
the radiated power limit on 60 meters. Perhaps someday we will have a
band, not just shared channels. Then maybe the TenTec 160 meter
transverter could be retuned for 60 meters.
--
73, Jerry, K0CQ,
All content copyright Dr. Gerald N. Johnson, electrical engineer
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