Icom AH-4 Universal Interface with KX3

[Terry]

I have an Icom AH-4 auto tuner that I would like to place at the feedpoint
of my horizontal loop so that when I tune, I will have 50 ohms coming
through the long run of coax to my rig instead of high swr.  I bought the
tuner when I had my ICOM rigs that would interface and tune directly to it.

 

I looked on the internet, and there are several universal interfaces, some
more complex than others.  I elected to go with the simple interface that
consists of a momentary switch, an led and 3K resistor in series as the the
main components.  The following link shows a photograph of the circuit.

 

http://pacificcoastsail.com/PCSC_working/Blog/BOAT%20RESOURCE%20LIST%20VIP/m
ods_dk%20-%20ICOM%20-%20AH-4_files/IC-AH3_and_AH4_wiring.gif

 

I have my KX3 connected to my KXPA100 but the tuner is bypassed.  I have
read that it requires at least 10 watts output from the rig to make the
circuit work.  If I set the TUN PWR to 10 watts and press the TUNE (not ATU
TUNE)  the power output shows 10 watts but when I press the momentary switch
to tune the AH-4, nothing happens and the tuner is not engaged and swr is
unchanged at 5.2:1..  

 

If I set TUN PWR to 20 watts and try it, the power output shows zero before
I can press the momentary switch.  .

 

The LED is 12V Led.  I have 12.8 volts into the circuit, and at the
terminals of the DC power receptacle where the circuit attaches, I read
3.66V with everything connected.

 

I would appreciate it if any others have gotten this circuit to work and
could tell me what I am missing.

 

Thanks,

 

Terry

 

 

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