[Elecraft] K3 and Expert 1.3

[Bob McGraw]

I'm really surprised that hams would expect ALC to be used to control 
power in any manner.  Yes, it can control power to some small limit.   
It is intended to, in general,  prevent amplifier damage in the event of 
a load failure or minor exciter spike or moment of excessive drive.    
But to expect one to dump the transceiver output into the input of an 
amp and expect to have ALC control the power.........that's old ham 
lore.  Not very smart operation either.

In the past I've used the ALC output of my KPA500 back to my K3S with 
ALC active.   Used correctly and monitored on the K3S, you'd never know 
that ALC was in the control path.    On the other hand, for those that 
must make that DX contact, set all knobs to the right and let the ALC 
handle the rest, that really makes a mess on the band.   Sounds like 
crap too.

Although the KPA500 is a bit less power than the Expert 1.3, there is no 
relay clicking when running full QSK and no fan noise.  I'm through with 
big noisy amp relays and with wind tunnel cooling systems.

73

Bob, K4TAX


On 10/5/2021 5:58 PM, elecraft-request at mailman.qth.net wrote:
> Message: 1
> Date: Mon,  4 Oct 2021 16:15:02 -0400
> From: Bill Frantz<frantz at pwpconsult.com>
> To: Mike March<mikek4qu at gmail.com>
> Cc:elecraft at mailman.qth.net
> Subject: Re: [Elecraft] K3 and Expert 1.3
> Message-ID:
> 	<r480Ps-10146i-02B923BAB0654A1BB83F7E374FAF0B06 at Williams-MacBook-Pro.local>
> 	
> Content-Type: text/plain; charset=UTF-8; format=flowed
>
> I have used an Expert 1.3K amp for several years with my
> upgraded K3. The short form is it works well. I got it when my
> wife won a $1000 off certificate. I knew this amp was a popular
> choice of many DXpeditions, and so worked well with the K3s they
> used and was reasonably reliable. When I got my amp, I also
> ordered a custom cable for the K3 which was delivered in the
> same shipment as the amp.
>
> I am careful to not depend on the ALC to control exciter power,
> but instead set the output power on the K3 to the right level to
> get the output power I want from the amp. I believe this
> procedure will result in a cleaner signal.
>
> I am thinking about replacing it with an Elecraft amp for two reasons:
>
>     Full break in CW produces a lot of relay clicking. The
> Elecraft amps use
>     PIN diodes.
>
>     The level of integration between the exciter (K3) and the amp
> is much
>     better. I can have my K3 operate at 100W when the amp is
> offline and at
>     whatever drives the amp to the right power level when the amp
> is online
>     with automatic switching.
>
> Cheers - Bill, AE6jV
>