[TenTec] circuits in modules Scout / 556

[Dr. Gerald N. Johnson]

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