[Elecraft] Triggering KPA500 from 2 Radios

[dmb at lightstream.net]

Hi David,

I've been doing this for at least a year, and it works fine. However, I
always leave the K3 powered ON when I'm using the other radios, and I can
switch between radios by switching only the coaxial switch. I just tried
turning OFF the K3 while trying to drive the amp from the KX3, and I see
the rx signal level on the KX3 drops, just as you stated. Turn the K3 back
on, and the signal level returns to normal, and the KX3 drives the KPA500
to around the 150 to 200 watt range. I currently have the KX3 and K2/100
set up with the K3 this way, and all work well.

I haven't experienced any adverse side-effects in doing this, and none of
the radios involved have lost any of their smoke.

73, Dale
WA8SRA



> I have been using my K3/KPA500 setup for quite sometime.  I am using the
> standard cable between the K3 ACC port and the KPA500 AUX for
> communications
> between the radio and the amp.  This has worked perfectly from the
> beginning.  At some time in the past, I wanted to use my Yaesu MKV Field
> to
> excite the amp.  I connected both radios tho the KPA500 through a
> 2-position
> coax switch.  I also connect a cable from the MKV  to the KPA PA. KEY
> jack.
> When I switched the amp from standby to operate, there was a huge
> attenuation of the MKV's received signal.  When I unplugged the K3-KPA AUX
> cable the problem went away.  The received signal level was fine and the
> amp
> produced +/-500 watts with about 40 watts of drive from the MKV.  An
> earlier
> message on the reflector indicated that this signal attenuation with the
> AUX
> cable connected was likely due to voltage signals on the AUX lines.  I
> remove the MKV from the system and forgot about.
>
> Well, I've rearranged my operating desk and would like to use the MKV a
> little; I sure do like operating "the old monster"!  Next to the K3 it is
> the best radio I have had on the desk.  So, back to the amp issue.  Has
> anyone connected two radios--one being a K3 using the AUX cable--to the
> KPA500, without having to plug/unplug cables to get everything to play
> nicely?
>
> 73 de K6SBA
> David in Santa Barbara, CA
>