My TxInh circuit diode or'd various inputs together. What I did not do is
put a
resistor to ground after the diodes. The K3 TxInh input does not have a
pull
down, and has a high enough impedance that there is an appreciable time
delay before the TxInh coasts down to where it allows the K3 to t
Mark,
It is good to hear that the resistor solved the problem.
If you had to add a pull-down resistor, that is not a K3 problem, that
is a requirement of whatever in your sequencer that is driving the K3 TX
INH line. In other words, whatever is driving your TX INH line is not
going to zero v
Although Mark has solved his INH problem, I thought I would share my
ckt for using the inhibit function with the K3 (in fact it also has
ckts for inhibiting a FT-847 which I no longer have):
http://www.kl7uw.com/TX-INHIBIT.htm
I use the Band-0 and Band-1 select functions to control VHF
inhibit
Be aware that Ed's circuit is much like mine in that it does not have a pull
down on the
TxInh line. Therefore it could act like mine did and extend the time till
transmit is
enabled. A resistor to ground might be a good addition if this is important.
Also as a side note, the kx3 is differe
Oops, the txinh in Ed's circuit is done with relay k4 which pulls the line to
ground, eliminating
Any ambiguity. My mistake was assuming k1 was doing this function, instead of
its clearly indicated action of switching control between the k3 and ft 847.
Mea culpa
Mark. N2QT
On Jan 27, 201
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