[Elecraft] Triggering KPA500 from 2 Radios

[Don Wilhelm]

David,

Yes, the AUX cable connected to the K3 will cause the KPA500 to "do 
strange things" when attempts are made to use the KPA500 with another 
transceiver.  And those "strange things" will depend on whether the K3 
is powered on or off.

May I suggest that you alter the K3 to KPA500 AUX cable by inserting a 
switch in line with it.
There are computer switches for SVGA monitors to switch one monitor 
between two computers.  Inserting one of those switches between the K3 
and the KPA500 should allow you to manually disconnect the K3 AUX cable 
when using  the MKV.

73,
Don W3FPR

On 5/2/2014 7:30 PM, David Inger wrote:
> 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?
>   
>