Greetings to all,
Thanks for all of the response to my last post. I was pleasantly
surprised at the number.
There really are a lot of different ideas on how the QSK-5 operates
and methods of it's use. Most are based on misunderstanding of the circuit,
but quite a few are based on good solid reasoning.
There seams to be two main misunderstandings; 1, that the QSK-5
responds differently to different modes of operation, 2, that the switching
has something to do with RF. Neither are correct. The QSK-5 has no way of
knowing what mode the transmitter is operated in. It works the same an all
modes (this is one of it's best features). The QSK-5 is nothing more than
an electronic switch which controls the bias that is applied to the PINS
allowing them to conduct, or not conduct.
Several people responded that their QSK-5 switched in 1 MS. The
PIN do switch in approximately 1MS, the mechanical relays simply DO NOT and
the mechanical relays must actuate before the pins can do their job. The
longest switching time in the system determines the overall switching time.
My tests show that these relays are very slow, in the order of 20 to 30 MS,
or even longer. Remember, this only applies to the first dit transmitted.
After that, the delay circuit keeps the mechanical relays activated until
several seconds after keying stops.
Back of the delay problem. First I suggest that you download N6MW's
great paper on understanding the QSK-5. To get full benefit of his paper,
be sure to print it out on a color printer. The different colors really
help tracing through the rather complicated circuit.
In this paper, N6MW shows several different ways of hooking the
QSK-5 to your station. Check the page that is headed "IS BLOCKING DIODE
HELL REQUIRED", in my copy, it is the next to the last page (there are no
page numbers). I tried all of the different setups except "C" because N6MW
seamed to not like this setup. After thinking about some of the responses I
received last night, I tried setup "C". In this setup, KEY1 and KEY2 are
basically switched at the same time avoiding the internal circuit delay when
connecting KEY1 to AUX (as in "A" and "B"). The improvement in operation is
very obvious because the mechanical relays simply keyed sooner.
I ran the delay tests again (changing QSK delay) and found that I
can now use a 20 or 25 MS delay time and get perfect keying. No more
missing of the first dit.
I still think that the internal board is the better way to go with
no relays, at all. I guess you could wire the original T/R relay to
by-pass the QSK-5 when the amp is turned off. I have not tried this, yet.
73 de Lon, K5JV
1110 Golden Bear Ln.
Kingwood, TX 77339
281-358-4207
281-358-4234 FAX
281-795-1335 CELL
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