[TenTec] Why a Scout drifts, correction

[Larry Kayser]

Re Scout

W5YR offers.....

"So, taking the keying task away from the cpu by using an external keyer
allows the cpu enough time to deal adequately with drift control."

Wrong answer.  The CPU has enough time but the VFO shifts frequency from RX 
to TX and there is not enough time to count the VFO frequency during the RX 
period to set the correction voltage up.  Eventually things reach their 
limits and the thing jumps frequency in the direction of drift.

The circuit is in fact excellent, the concept is excellent, the change in 
VFO frequency from RX to TX is what screws up the process.  There is not a 
simple way to keep the VFO on one only one frequency unless one was to 
switch the BFO frequency as an alternative.  There were design options, I 
have figured out three of them - there may be gotcha's in the alternative 
designs as well.

Larry
VA3LK