FT897D and KPA500

[David Mitchell]

I am having difficulties keying my KPA500 from my Yaesu FT897D.  It has no
dedicated PA Out jack. The CAT/Linear jack is currently in use transmitting
band data to the RS-232 port on my computer and I had hoped to use the ACC
jack to key the amp.

I can get a connection for ALC voltage through the tip of that stereo
connector, but the ring wants to be brought to ground to transmit.  I have
a Quicksilver "Tune-Rite" that does just that and if I connect the amp PA
key and the Tune Rite using a "Y" connector the amp keys fine, but I can't
key it from the rig itself since the PA input wants to be brought to ground
to transmit.

Any creative suggestions on how to get a PA key output from my FT897 are
appreciated.

-- Dave WB2PJH
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[Phil Salas]

“I am having difficulties keying my KPA500 from my Yaesu FT897D. It has no dedicated PA Out jack. The CAT/Linear jack is currently in use transmittingband data to the RS-232 port on my computer and I had hoped to use the ACCjack to key the amp.”

The TX GND output on the CAT/Linear jack is active no matter how the CAT/Linear jack is used.  Just bring out the leads for TX GND and use that to key the amplifier.

Phil – AD5X
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[Dave Johnson]

Dave, I used to have an FT857D, which is probably the same
connections. The 857 has a connection in the mini DIN socket that will
ground the keying input of a low voltage keying line of a linear, I am
not sure of the maximum voltage but 12 volts from the Acom was OK. I
used my 857 with an Acom 1000, so the same output will also key a
KPA500. I do not have the circuit to hand but it will be a
straightforward (if a bit fiddly) connection.

Beware that the FT857D and no doubt the 897D, is prone to serious ALC
problems which result in high power spikes on transmit. See
http://www.astromag.co.uk/ft857d/ for details and a "work around".

73 Dave, G4AON

>I am having difficulties keying my KPA500 from my Yaesu FT897D
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