Larry, thanks for your info and viewpoint.
But, why does using an external keyer avoid the problem?
I am afraid that I don't follow this one . . . see comments below.
Larry Kayser wrote:
>
> 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.
If "there is not enough time to count . . ." why do you say that my quoted
statement is wrong? Without the need to deal with code elements/characters,
the CPU *would* have time to count, etc. Hence, an external keyer allows
the CPU adequate time for frequency management. Right?
How can "The CPU has enough time . . ." be true when "there is not enough
time to count the VFO frequency during the RX period . . ." ? Doesn't that
mean that the CPU is, in fact, too slow to handle both keying and frequency
management when keying speed reaches or exceeds about 25 wpm?
> 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.
I gather then that because the CPU is not fast enough to count the VFO
frequency during the RX period, that is why slow keying with more space
between code elements and perhaps longer periods of not transmitting gives
the CPU "time" to catch up and put the PTO back on frequency.
Larry, it sounds like you are infinitely more familiar with this rig and
its problems than I am, so I defer to your opinion, but I sure don't
understand what you are saying. <:}
72/73/oo, George W5YR - the Yellow Rose of Texas
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
Amateur Radio W5YR, in the 56th year and it just keeps getting better!
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