On Thu, 16 Dec 2004 14:51:44 UTC, K7MEM wrote:


I fully agree with you that, done right, QSK is a delight. I have been
using a Heathkit HR-1680/HX-1681 combination for over 20 years now.
The QSK works extremely well. It is virtually imperceptible that the
receiver is actually being shut down during my dots and dashes. There
is no thumping or bumping or hammering of the S-Meter, and I can hear
all of the band activity.

IMHO, I think that to have a good QSK setup, you must take the capabilities
of both the receiver and transmitter into account. This Heathkit pair
was designed to work together. There is a keying circuit inside that
controls the timing of the receiver muting, transmitter keying, and
T/R switch operation. No relays are involved at all. The low level
keying and frequency generation is all solid state and the final (tubes)
is run Class AB2, for a nice clean, well shaped, signal.

It may be beneficial to get a copy of the HX-1681 transmitter and
investigate how they implemented it. I haven't looked at the schematic
in a long time but I don't think it was very complicated. It may be
similar to Tentec's concept of QSK.

I also seem to remember that in the ARRL Handbook, 2000 I think,
there was a project for making implementing automatic T/R switching
for vintage transmitters and receivers. I don't remember if they went
into full QSK, or not, but it's another possible resource.

I'm hoping that www.radioadv.com version of the Handbook TR-Keyer
will supply that level of control.

I'm not in a rush to get this going. I'm mostly a listener and
haven't been on HF for decades. I have a TH3jr and a 204BA (with
35 foot boom) both disassembled. I've been refurbing receivers.
While I work on them, I'll listen to 40 CW or one of those 75 meter
nets.

I like to listen a couple times a month to keep my copying speed up.

The more I hear about that handbook/radioadv TR-keyer, the more
exciting it sounds. If it'll give me good QSK like a Triton IV or
your HR-1680/HX-1681, it'll be well worth it.

de ah6gi/4 qsy to 80 to listen for the QRP sprint.

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