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Re: Preamp bypass circuit



I like your idea, but it should go even further:

Instead of a "TX inhibit" input, there should be a "TX enable" input.
(The difference being that if you have nothing hooked up to the input,
the radio does not transmit.)

There should also be an "TX request" signal that is generated from the 
mike's PTT button, the VOX, the front-panel Xmit button, the TNC port's
xmit input signal, etc.  "Normal" users would jumper the two signals
together, either with a real jumper plug, or a software-controlled virtual
jumper.

People who need to use sequencers or delays would break the jumper and
connect the two signals to their own circuitry.  This way, they could still
use the stock PTT/Xmit switches, and everything would be 100% foolproof.
Problems like broken wires or accidentally-pulled-out plugs would
not cause a disaster.

I am really surprised that $2000 specialty satellite radios do not 
already work this way.

Another beef:  My IC821 has a "preamp" button, and when you turn it
on, it puts 12 volts DC on the output only when receiving.  But
there is no way to program the radio to provide a delay between the
time the voltage is dropped, and the transmitter actually starts
up...



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