[AMPS] amp t/r control

[Joe Subich]

In <12348@icefog.gcgo.nasa.gov>, on 04/29/97 
   at 06:06 PM, kl7ra@icefog.gcgo.nasa.gov (KL7RA Fairbanks Alaska) said:

>Although not as elegant as the hardware xmit/rcv sequencer you suggest
>there is now available with some of the contest software comparable
>amplifier t/r controls (N6TR).

Another idea for handling the keying "problem" is the TR control board 
used in QRP equipment from Kanga Products (http://qrp.cc.nd.edu/kanga/).
The circuit normally switches transmit/receive voltages and drives the T/R relay.  The T/R control board delays input keying slightly (~2 mS) to allow the R -> T switching to be complete before RF is generated and adds an adjustable "hang" on T -> R preventing hot switching in that direction. 

The circuit could be modified slightly to key an amplifier relay (and perhaps, with the addition of "mode select" logic, the rig PTT for those rigs that tend to clip the first element) BEFORE the key line and release the amplifier relay after an adjustable delay.  Delaying the key line by 2 mS on "make" and adding a 5 mS hang on "break" should provide very clean operation without effecting QSK performance, even at 60 WPM. 

73, 

   ... Joe Subich, W8IK  ex-AD8I
       <W8IK@ibm.net>
       <jsubich@ibm.net>


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