[Elecraft] KPA-1500 wish list

[Doug Turnbull]

Bob,
    I was thinking of ALC between K3 and an external amplifier.    Your
point is taken; first trim the K3 properly.
                      73 Doug EI2CN

-----Original Message-----
From: elecraft-bounces at mailman.qth.net
[mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Bob McGraw K4TAX
Sent: 18 November 2019 18:08
To: elecraft at mailman.qth.net
Subject: Re: [Elecraft] KPA-1500 wish list

At risk of starting a FIRE storm here in the group, why not CORRECTLY 
configure the ALC between the amp and radio.  Just remember it is not a 
power control application but no different than the normal ALC in your 
radio.  You do use that don't you? And you can see the amp ALC on the 
K3S display ALC indication.  It will let you know if you are punching it 
too hard.

73

Bob, K4TAX


On 11/18/2019 11:55 AM, Doug Turnbull wrote:
> Dear OMs and YLs,
>       Why not just run 1400 Watts.    The difference in power will never
be
> noticed by anyone you are working.    It should reduce stress on the
KPA1500
> components.   Though feedback which is after all what we are talking about
> can not only reduce distortion but in some instances introduce distortion;
> ALC being just one example.   If your SWR forces the return power to over
> 200 Watts then it seems to me there is the more important problem to
> address.
>
>       I am sorry if I have stepped on any toes.   This is not my intent.
I
> too run a KPA 1500 which is a delight.
>
>                     73 Doug EI2CN
>
> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Rick Tavan
> Sent: 18 November 2019 17:45
> To: N4ZR; Elecraft Reflector
> Subject: Re: [Elecraft] KPA-1500 wish list
>
> I'd love to have something like this, Pete!  It's not only frequency
> excursions that cause output fluctuations but also warm-up. The gain of
the
> power transistors is temperature-sensitive. I'd like to be able to set a
> target output power (typically 1500w but maybe less on bands with
> mismatched antennas or in countries with lower power limits), have
> *something* monitor it, and send drive adjustment commands to the K3 via
> sharing the serial port. (The commands exist - PC and PO.) It's not the
> same as AGC which is analog and real-time and can cause distortion. I've
> called it "Slow AGC" because it would only operate every second or so,
> perhaps taking multiple cycles to recover a desired output power and
> causing no measurable distortion. It would essentially duplicate what we
do
> manually - keep a sharp eye on the power and tweak the K3 PWR control
> appropriately. That's not only a significant drain on brain and muscle
> cycles over the course of a long operating session as in contesting but
> also useful in less extended situations like the excitement of a DX
pileup.
> It would require software in the KPA1500 and maybe also an external box or
> computer where port sharing would take place. (It could also be done
> entirely external to the KPA1500 by replicating its power sensing
> circuitry, a bit of a waste.) It's not trivial but I'm convinced it's
> possible.
>
> 73,
>
> /Rick N6XI
>
> On Mon, Nov 18, 2019 at 8:31 AM N4ZR <n4zr at comcast.net> wrote:
>
>> Here's one that I kept running into.  My K3/KPA-1500 when operating at
>> one end of the band on 40 and 80, would work fine, but when I went to
>> the other end  I found that often I would be running over 1500 watts,
>> and sometimes, the result would be reflected power exceeding 200 watts,
>> causing a fault.  For those of us who have the Aux port cable connected,
>> wouldn't it be pretty simple for the KPA-1500 to turn down the K3's
>> power to limit output to 1500 watts?
>>
>> --
>>
>> 73, Pete N4ZR
>> Check out the Reverse Beacon Network
>> at <http://reversebeacon.net>, now
>> spotting RTTY activity worldwide.
>> For spots, please use your favorite
>> "retail" DX cluster.
>>
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