[Elecraft] KX2 / KPA500

[Mark Goldberg]

My confusion is connecting the KPA500 to both the KX2 and K3 at the same
time. I use my KPA500 with two different radios, but it is only connected
to one of them at a time. In my case it is:

RF, RS232 and PTT in from my TS-590S
OR
RF, and PTT in from my KX3

I assumed that pull ups / downs when units are not powered up would mess
things up and they are not designed to be wired ored,  especially when not
powered up. Since I don't have a K3, I don't know how it connects up.

73,

Mark
W7MLG


On Tue, Apr 28, 2020 at 4:48 PM Jack Brindle via Elecraft <
elecraft at mailman.qth.net> wrote:

> I went back and reread this . My question is this - with the interrupter
> in place, does the K3 still key the amplifier?
>
> I suspect you are running into the issue of pull-ups on the K3 pulling the
> PTT signal up to Vcc. Of course Vcc when the K3 is off is 0 volts, which
> causes the KPA to key.
> We see the same issue with the BAND lines, which is why the KPA500
> switches to 60 meters shortly after the K3 is powered off.
>
> So, I’m wondering what is going on also. More details and tests should
> resolve the questions.
>
> 73!
> Jack, W6FB