Lots of good comments on the reflector already, but I will pass along my
observations.
Getting an amplifier to close relays quickly enough is not a problem, maybe
even without resorting to the vacuum relay speed-up circuits. Even
sequencing them to close and open in the correct order is relatively easy,
depending on the relays you have available. All of this has been covered
in excellent detail by Rich Measures, AG6K and others.
Background:
When you go key down on the Omni 6+, after some setup delay in the
transceiver, the "TX OUT" line on J-1 goes low (to ground). When the
factory jumper is installed, it pulls "TN ENABLE NOT" on J-2 down and the
transmitter goes on the air.
This is important: In my Omni 6+, if you pull "TX ENABLE NOT" down on
J-2, no matter what the state of the operator's mind or the condition of
the remainder of the station, the transmitter goes on the air. This allows
a failure external to the transceiver to put Omni into transmit, even
though that may not be what you had in mind.
I believe the optimal solution would be for the Omni to go into transmit if
both J-2 and J-1 were driven low, that way only a response to the Omni
transmit request would put the transmitter on the air. That would require
additional logic in the transceiver.
I tried to the "Y-cable" trick, and the Omni didn't like the pull-up
voltage on the opto-isolator I ground to key the amplifier. You might be
able to get around that with either an emitter-follower or FET input to the
amplifier that didn't confuse the existing Omni signalling. Another
possibility might be to pick off the collector of Q-16 and bring it out to
an external connection, and you could still keep the TXHang programmability.
Anyway, I wimped out before solving the problem, settling out of court for
the relatively inoffensive built-in relay. If anyone nails this, I would
like to hear your approach.
Very 73,
Hank
AA4HP
At 01:59 AM 12/1/2005 +0000, you wrote:
Hi-
I have an OMNI VI and a TL-922a amp which I just finished wiring with
vacuum relays for QSK fast switching. Works great but, the OMNI relay
used to key non Ten Tec amps is annoying on CW. (Not real annoying but....)
Of course when not using the amp, which is 99.9% of the time I can
switch the relay off and have quiet CW.
Is there any reason why I can't tap into the TX EN and TX OUT jumper
with a "Y" connection and run the quiet transistor switching to ground
since TX OUT does go to ground when its active and then leave the relay OFF?
73 de Dave in NH K1OPQ
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