[Elecraft] Externmal ATU

[Lu Romero]

Phil:

Yes and no.  I once wanted to build a "AT300 simulator" and
use DIGOUT but there is a more elegant and simple way to fix
this.  And you also protect yourself in case you forget to
tune if you set the tuner on AUTO and let it take care of
business.

I also have a K3 with an ALS600 and a MFJ998 and these
methods work for me.  I Just use the XMIT button and not the
ATU TUNE button.  They are right next to each other.

First, set the 998 tuner in auto mode.  Then, PRESS AND HOLD
the XMIT button on the rig (its labeled TUNE for a
reason...).  This outputs a carrier, in my case, ten watts,
from the rig (its adjustable under TUNE POWER in the menu). 
If I have the amp triggered by the KEY OUT socket of the K3,
this then keys both the rig and the amp and makes around 50
watts of power which the tuner finds acceptable.  If I have
the amp bypassed, the tuner can still tune using the 10
watts.  Since I "preset" the tuner on each antenna/band by
doing a tuning cycle every 10kHz (thereby pre-setting the
memories, the '998 has zillions of them!) and since my
antennas are rather consistent, it takes about half a second
for the tuner to snap in the L and C components and Im ready
to go.  You just have to remember to PRESS AND HOLD the XMIT
button then PRESS AND HOLD it again.  Just TAPPING it turns
on PTT on SSB and you get no carrier out.  TAPPING it on
RTTY gives you full output, and the tuner sends "QRP"
because it cant tune at 500+ watts.  This works perfectly
for a solid state amp.

Another way is to place a momentary normally open push
button on the K3 built in keyer line (since I use computer
keying, it has nothing in it) or even a spare CW paddle in
it and set the WPM at around 25 on the radio.  Closing the
switch sends a series of dits (or dahs, your choice) from
the internal keyer (that I dont use anyway) and the tuner
will set itself on that.  Since I am using a MicroKeyer to
assert PA PTT and not the internal KEY OUT, and Im using the
internal keyer and not the MicroKeyer, the amplifier is not
triggered and only the exciter power is output to the tuner,
which it is happy with (in my case, 65w output).  I dont do
it this way anymore, but when I had a tube amp, this was a
cheap and dirty way to get a amp keying "pulser".

Hey, I paid for that K3 internal keyer!... I wanted to put
it to use!

As an aside, thanks again so much for designing the AL600
Full QSK kit!  I have had one installed since my ALS600 went
out of warranty in March.  It is simply WONDERFUL!  It
should be a required modification to that amp!  I see
Ameritron has done a similar feature on the ALS1300.  Hope
you got something for that idea :)

-lu-w4lt-
K3 S# 3192

  

Message: 11Date: Tue, 24 Aug 2010 10:52:47 -0500
From: "Phil & Debbie Salas" <dpsalas at tx.rr.com>
Subject: Re: [Elecraft] Externmal ATU
To: <elecraft at mailman.qth.net>
Message-ID: <F459B5FC07C34992BDA8A0AA09723477 at OwnerPC>
Content-Type: text/plain; format=flowed;
charset="iso-8859-1";
    reply-type=original

"Phil.

 > The problem is that the K3 needs an external input to put
it in the
 > TUNE mode.  I have the KAT3, but I need an external
autotuner for
 > use with my ALS-600 amp.  So I have this same issue with
my MFJ-998
 > autotuner.  The MFJ-998 puts out a control signal
(ground) before it
 > starts tuning to automatically put a transceiver into a
CW TUNE mode.

I believe you will find the (Straight) Key input will
provide a carrier
in any mode if you turn on "CW in SSB" and enable VOX.  It
has been
used that way with the Yaesu Quadra which requires a carrier
for its
F-Set function.

73,

    ... Joe, W4TV"

Joe - The problem is that now you'll transmit at full power
when you key the 
radio.  Not good for most external autotuners.  And probably
not wonderful 
for the K3 output when playing into a relay-switched
autotuner at full 
power.  I like the way so many other radios do it whereby
the input from the 
external tuner puts the radio in a low-power TUNE mode.

Phil - AD5X