[Collins] KWM2 Tuning

[Dr. Gerald N. Johnson]

On Sun, 2008-10-26 at 17:35 -0400, bill riches wrote:
> Noticed when listening on 20 meters (14.2 MHz) and the “exciter
> tuning” is set to 7.0 MHz or so I can hear other signals – what is the
> mixing formula to figure out these frequencies?
> 
>  
> 
> 73,
> 
>  
> 
> Bill Riches, WA2DVU
> 
> Cape May, NJ
> 
> 
For the lower tuning point, lower edge of the tuning range is the
crystal frequency - 3.155 MHz. Normally above 12 MHz, its the crystal
frequency times 2 - 3.155 MHz. Because the trimmer capacitors are
different on each band, the prescaler frequency calibration isn't
correct.  e.g. the 14.0 band uses injection at 17.155 MHz from an 8.5775
MHz crystal on its second harmonic. On its fundamental you are tuning up
from 5.4225 MHz. Then you might be tuning down from 11.7325 MHz. Depends
on how the RF and oscillator slugs are tracking.  You should bee able to
work out which you are tuning by use of the 100 KHz crystal calibrator.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer