Hello folks,
I'm trying to build a simple relay circuit to key a Yaesu FL2100B
amplifier. The amplifier uses negative keying voltage, so I need to have
some sort of interface in between the K3 and the amp (Per the manual,
the K3 supports +200v but not negative voltage).
If I put an ohm meter on the K3's key out jack, and hook the positive
lead to the center conductor, and the negative lead on the shield, I
measure an open when the K3 is not keyed up, and measure a short when
the K3 is transmitting. So far so good..
I built a simple circuit that looks something like this:
Center conductor on K3 Key line
|
|
|
+12V from power supply ------ ----------------Relay
coil
|
|
Shield on K3 Key line
-12v from power supply ------------------------------------Relay coil
When I DO NOT have the K3's key out plugged into this circuit, and short
the RCA cable, the relay closes & the circuit works. Again, so far so
good.....
However, when I try this plugged into the K3 and hit the transmit, the
relay does not close.
Why would I be able to measure a short on the K3's key out when
transmitting, however it will not bridge my 12v & close the relay circuit?
I hope I'm not doing something very stupid here :)
Thanks,
W9PDS
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