Let's talk about the keying on the Omni 6 that Del Seay mentioned. I've
heard some that sound fairly good and others that stink to high heaven.
Last night while I had the rig opened up and was QSOing K5CX, I ran some
checks with him. I also monitored my signal in another receiver.
Cranking R24, the keying adjustment, fully counterwise produced an obvious
click in my monitor rx. Jim even said it had a chirp. Turning it almost
all the way down removed the chirp and smoothed out the click. Jim was
still reluctant to give me an "excellent" keying report.
There are two items that bother me about the keying set up.
1. The 9mhz xtal's frequency is shifted as the rig is keyed (typical of
most systems) but this seems to be where the click or pop originates that
is finally reproduced in the speaker. Adding filtering to the cw-t supply
voltage that keys the xtal will greatly smooth out the pop and no doubt
cure the sharp keying but if you hold the key down long, the electrolytic
will begin to charge and gradually cause the frequency to change. This is
not a good solution but a step in the right direction.
2. The output of the balanced modulator mixes the 9mhz rf with the dc
keying voltage. It looks awful on a scope. You see a huge jagged pulse
with the poor little RF signal riding going along for the ride, not a
pretty sight.
Tonight I may try experimenting with regulation of the cw-t voltage on
that xtal and see what happens. Stay tuned. 73
Steve Ellington N4LQ@IGLOU.COM Louisville, Ky
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