[Elecraft] KPA500 with K3 in TUNE mode?

[Nels Anderson]

I'm confused as to why the aux bus is referred to as being one way.

Just received KPA500 #32 yesterday and starting playing around with it. 
When I change bands on the K3 the band automatically changes on the 
KPA500 (as indicated by the display). When I use one of the band buttons 
on the KPA500 to change bands, the same band change takes place on the 
K3. To me that sounds like two way communications. Still more learning 
to do to maximize ease of operation though :-)

73 Nels K1UR

On 5/13/2011 8:48 AM, Randy Farmer wrote:
> I didn't realize the AUXBUS comms were one-way. Turning the TUNE level
> down to a few Watts would work OK with the 235 and the KPA500 on-line.
> Unfortunately, I have another antenna matched with a SG-230 that I want
> to use as well. I don't know if the low level would be enough for the
> 230 or not. I'll do some experimenting to see what it takes.
>
> It would be nice if an Amp Inhibit signal were available. Maybe some day.
>
> Thanks for the advice.
>
> 73...
> Randy, W8FN
>> The AUXBUS provides one-way communication between the KPA500 and the K3
>> (KPA500 to K3).  So the KPA500 won't know that the K3 is in TUNE mode.  The
>> KPA500 has about 12-13 dB gain, so if the SG235 can take up to 100 watts
>> without problems, you could set the TUNE mode to output no more than 5-watts
>> for tuning.  Unfortunately the K3 amp-enable output is always active whether
>> in TUNE mode or normal operating mode (I understand this is hard-wired and
>> so can't be changed in firmware).
>>
>> What would be nice is if the K3 would output a signal (Dig Out 0 or Dig Out
>> 1?) that would feed the amp-inhibit input on the KPA500 (pin 11) when you
>> press TUNE on the K3.  Not sure if this is possible, but that would do the
>> trick.
>>
>> Phil - AD5X