[Elecraft] KAT500/KPA500 with Icom 7100

[Dick Dievendorff]

The 4-wire AH4 connection doesn't PTT key the amp. It has 12v, ground, Start, which is a signal from the Icom to the tuner that is asserted when you press the Icom tune button, and ah4 key, which is asserted by the tuner when it needs a tune level signal from the Icom.  The amp needs a separate PTT key line from the Icom RCA connector to the kat500, and another RCA cable from kat500 to amp.  The AH4 Key line is distinct from exciter to amp PTT and although both have key in their names, they have different purposes.

One of our diagrams in the owners manual may have omitted the RCA keying cables. A manual revision is in the works. 

73 de Dick, K6KR

Sent from my iPhone

> On Nov 6, 2013, at 5:43, "Jeff Griffin" <kb2m at comcast.net> wrote:
> 
> I brought my KAT500/KPA500 setup to my winter home after getting it put
> together and working with my K3 at my shore residence. Now I'm trying to get
> it working with my Icom 7100. After setting up the Elecraft pair, only menu
> item I see to set is in the KPA500, RADIO, set to ANALOG. I'm having two
> problems. 
> 1. I'm not getting PTT to activate. I checked the AH-4 interface cable and
> it has the correct pinout. If I ground the center pin of the RCA PTT cable
> the AMP keys as expected. The problem is the 7100 isn't grounding pin one.
> Does anyone know if there a config command in the 7100 to activate this? I
> can't find anything. When you key up the 7100 the pin stays open and not to
> ground as I think it should be doing.
> 2. I'm not getting any band switching with this setup. If I click on a spot
> with DXLab I would expect the Elecraft pair to follow the 7100, I'm thinking
> if problem 1 is fixed problem 2 will also be ?
> 
> All other AH-4 functions seem to be working ok. The cable powers the KAT500,
> and If I hit the tune button on the 7100 the KAT500 obeys.
> 
> Coolaid drinkers, yes I know if I replace the 7100 with another K3 my
> troubles will be over :-)
> 
> 73 Jeff kb2m    
> 
> 
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