[Elecraft] [K3] GPIO input to switch output power with external amplifier on?

[Joe Subich, W4TV]

On 9/4/2012 8:29 AM, Thomas Horsten wrote:
> I am wondering if anyone knows how the KXPA500 signals its state to
> the K3.

Per previous information, proprietary serial protocol on pin 2 (AUX
bus).

 > What cable is used to interconnect the two?

15 pin HD - KPAK3AUX.  see:
http://www.elecraft.com/manual/KPAK3AUX%20Cable%20Set%20Instructions.pdf

 > There might already be a GPIO

No - read the K3 Owner's manual for a description of the GPIO signals
on the ACC connector.

73,

    ... Joe, W4TV


On 9/4/2012 8:29 AM, Thomas Horsten wrote:
> I am wondering if anyone knows how the KXPA500 signals its state to the K3.
> What cable is used to interconnect the two? There might already be a GPIO
> on the extension connector that enables the alternative power settings on
> the K3 on a per band basis.
>
> Any info? Of course if there isn't wouldn't it be great if Wayne could add
> it :)
>
> 73, Thomas M0TRN
>
> On 29 August 2012 01:52, Vic K2VCO <k2vco.vic at gmail.com> wrote:
>
>> I also have suggested this. I wrote a macro which toggles the DIGOUT1 line
>> which I use to
>> enable/disable my 'dumb' amplifier. The macro also switches between 100w
>> and 65w, which is
>> more or less what I use to drive the amplifier. But I would really like to
>> have access to
>> the per-band settings used for the KPA500.
>>
>> This feature is only available if you have a KPA500 now, but it shouldn't
>> be hard to make
>> it accessible to everyone.
>>
>> On 8/28/2012 4:41 PM, Thomas Horsten wrote:
>>> Hi all,
>>>
>>> I know that the K3 can remember a separate power level for transmitting
>>> with an intelligent external amplifier like the KPA500, but I have an old
>>> boat-anchor amplifier which I switch in and out with a simple switch
>>> connected to the KEY OUT line of the K3.
>>>
>>> Sometimes I am working barefoot on the K3 with 100W and then I decide I
>>> need some extra power and turn on the amplifier. Then I have to turn the
>>> drive down on the K3 to about 40W to drive the amplifier, but sometimes I
>>> forget and the result is amplifier overdrive and burnt smell from the
>> tubes.
>>>
>>> It would be very nice if there was an input on the K3 that would switch
>> to
>>> the alternative per-band memory for drive power. It might already be
>> there
>>> and used for the KPA500, but I couldn't find it in the manual.
>>>
>>> 73, Thomas M0TRN
>>
>>
>> --
>> Vic, K2VCO
>> Fresno CA
>> http://www.qsl.net/k2vco/
>> ______________________________________________________________
>> Elecraft mailing list
>> Home: http://mailman.qth.net/mailman/listinfo/elecraft
>> Help: http://mailman.qth.net/mmfaq.htm
>> Post: mailto:Elecraft at mailman.qth.net
>>
>> This list hosted by: http://www.qsl.net
>> Please help support this email list: http://www.qsl.net/donate.html
>>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Elecraft at mailman.qth.net
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>