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Externmal ATU

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Nr4c

Externmal ATU

I have a nice new K3/100. I am not ready to add the ATU yet. But I have
both an LDG AT11mp and an ICOM AH-4 (in the car). Has anyone figured how to
interface one of these tuners to the K3 so that it works off the ATU button,
just as they do with my ICOM-706MKiig?

Currently I'm using the LDG on the table with the radio, HOLD the TUNE
button, hit the LDG Tune button and adjust as necessary. Release the K3
TUNE button. It works well enough, but it sure would be nice to just TAP
the ATU button. I'm thinking of taking it on a trip this weekend, and would
like to use the AH4 with my mobile antenna. The required signals are
probably on a plug on the RF board, just waiting for a connector and cable.

Thanks....

....bc nr4c

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Don Wilhelm-4

Re: Externmal ATU

Bill,

I would assume that you have the LDG interface cable for the Icom.
Unfortunately, LDG does not make a similar cable for the Elecraft K3.

You could go to a lot of trouble and reverse engineer the LDG cables and
then adapt them to the K3, but for the time and effort involved, it
might be more economical to just spring for the KAT3 - it depends on how
much you value your time and effort. Yes, creating your own custom K3
to LDG cable may be a fun exercise, it may or may not be economically
feasible depending on the value you place on your time and effort.

73,
Don W3FPR

Bill Conkling wrote:

> I have a nice new K3/100. I am not ready to add the ATU yet. But I have
> both an LDG AT11mp and an ICOM AH-4 (in the car). Has anyone figured how to
> interface one of these tuners to the K3 so that it works off the ATU button,
> just as they do with my ICOM-706MKiig?
>
>
>
> Currently I'm using the LDG on the table with the radio, HOLD the TUNE
> button, hit the LDG Tune button and adjust as necessary. Release the K3
> TUNE button. It works well enough, but it sure would be nice to just TAP
> the ATU button. I'm thinking of taking it on a trip this weekend, and would
> like to use the AH4 with my mobile antenna. The required signals are
> probably on a plug on the RF board, just waiting for a connector and cable.
>
>
>
> Thanks....
>
>
>
> ....bc nr4c
>
> ______________________________________________________________
> Elecraft mailing list
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>

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Phil Salas

Re: Externmal ATU

"...You could go to a lot of trouble and reverse engineer the LDG cables and
then adapt them to the K3..."

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. Many transceivers have
this capability - FT857/897, Yaesu MKV, IC-706/7000 are ones I know of.
Sooner or later the K3 will need this external TUNE REQUEST input if
Elecraft does build an external tuner for their amplifier.

Currently, I leave my MFJ-998 in the full auto mode so it starts tuning when
the SWR goes above 2:1. So whenever I change bands or antennas, I manually
enable TUNE on my K3 (output set for 15 watts). If SWR is greater thyan 2:1
the MFJ-998 interrupts the ALS-600 key line, tunes, and then re-enables the
amp key line (a neat feature of the MFJ-998). But since it takes some
milliseconds for the tuner to recognize there is an SWR problem, the
amplifier momentarily sees a high SWR before the MFJ-998 takes it off-line.
With the TUNE output of the K3 set for 15 watts, I haven't had problems with
the ALS-600 tripping out during this short time period. However, if the K3
had a TUNE REQUEST input, then punching the TUNE button on the MFJ-998 would
disable the amp first before enabling the TUNE ouput of the K3 (the MFJ-998
timing is set up this way).

Phil - AD5X

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Joe Subich, W4TV-4

Re: Externmal ATU

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

On 8/24/2010 7:03 AM, Phil & Debbie Salas wrote:

> "...You could go to a lot of trouble and reverse engineer the LDG cables and
> then adapt them to the K3..."
>
> 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. Many transceivers have
> this capability - FT857/897, Yaesu MKV, IC-706/7000 are ones I know of.
> Sooner or later the K3 will need this external TUNE REQUEST input if
> Elecraft does build an external tuner for their amplifier.
>
> Currently, I leave my MFJ-998 in the full auto mode so it starts tuning when
> the SWR goes above 2:1. So whenever I change bands or antennas, I manually
> enable TUNE on my K3 (output set for 15 watts). If SWR is greater thyan 2:1
> the MFJ-998 interrupts the ALS-600 key line, tunes, and then re-enables the
> amp key line (a neat feature of the MFJ-998). But since it takes some
> milliseconds for the tuner to recognize there is an SWR problem, the
> amplifier momentarily sees a high SWR before the MFJ-998 takes it off-line.
> With the TUNE output of the K3 set for 15 watts, I haven't had problems with
> the ALS-600 tripping out during this short time period. However, if the K3
> had a TUNE REQUEST input, then punching the TUNE button on the MFJ-998 would
> disable the amp first before enabling the TUNE ouput of the K3 (the MFJ-998
> timing is set up this way).
>
> Phil - AD5X
>
> ______________________________________________________________
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Nr4c

Re: Externmal ATU

The discussion below is one approach, but not the situation I am
dealing with. I am looking for a way to access the signal from the K3
that tells the ATU to TUNE. I want to use the front panel ATU button
to start the TUNE process, not a button on the tuner. Leaving the
tuner in AUTO mode is an annoyance I really don't like. There has to
be a signal that tells the internal ATU to start tuning, so I want to
acess that signal to send to my LDG or AH-4.

...bc

>
> 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.
>
>>

M0XDF

Re: Externmal ATU

Does your LDG or AH-4 tune on RF sense? You can use the TUNE function (hold XMIT) to send RF and the power of that is adjustable.
73 de M0XDF, K3 #174, P3 #108

On 24 Aug 2010, at 15:03, [hidden email] wrote:

> The discussion below is one approach, but not the situation I am
> dealing with. I am looking for a way to access the signal from the K3
> that tells the ATU to TUNE. I want to use the front panel ATU button
> to start the TUNE process, not a button on the tuner. Leaving the
> tuner in AUTO mode is an annoyance I really don't like. There has to
> be a signal that tells the internal ATU to start tuning, so I want to
> acess that signal to send to my LDG or AH-4.

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Don Wilhelm-4

Re: Externmal ATU

In reply to this post by Nr4c

The "signal" you are seeking in the K3 is a decode of AUXBUS data. It
does not exist as a single signal line.

73,
Don W3FPR

On 8/24/2010 10:03 AM, [hidden email] wrote:

> The discussion below is one approach, but not the situation I am
> dealing with. I am looking for a way to access the signal from the K3
> that tells the ATU to TUNE. I want to use the front panel ATU button
> to start the TUNE process, not a button on the tuner. Leaving the
> tuner in AUTO mode is an annoyance I really don't like. There has to
> be a signal that tells the internal ATU to start tuning, so I want to
> acess that signal to send to my LDG or AH-4.
>
> ...bc
>

KK7P

Re: Externmal ATU

The K3's ATU function is handled within the MCU. It is an internal
logic state, not a physically accessible signal, that actuates the ATU.

73,

Lyle KK7P

>> ...I am looking for a way to access the signal from the K3
>> that tells the ATU to TUNE.
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Phil Salas

Re: Externmal ATU

In reply to this post by Joe Subich, W4TV-4

"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

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Jack Brabham KZ5A

Re: Externmal ATU

In reply to this post by KK7P

Bill,

I ran into this problem a few months back and swapped several emails
with Wayne about it.

Currently there is no specific support for external tuners from the K3,
so the method you are using is the only possibility.

I did some research on external auto-tuner protocols for Wayne and my
understanding of the ensuing discussion was that Wayne was going to
implement Kenwood AT-300 hardware handshake protocol in the K3. This is
a the common Kenwood 2 wire/2 way interface and allows for tuner
initiated auto tune sequences as well as enabling the K3 TUNE button to
function normally with an external autotuner.

The initial estimate for availability was a couple of months ago. I
have no idea where this is currently on the "enhancement list" for the
K3 but I'm still looking for it, and hopefully soon.

73 Jack KZ5A

On 8/24/2010 10:05 AM, Lyle Johnson wrote:

> The K3's ATU function is handled within the MCU. It is an internal
> logic state, not a physically accessible signal, that actuates the ATU.
>
> 73,
>
> Lyle KK7P
>
>>> ...I am looking for a way to access the signal from the K3
>>> that tells the ATU to TUNE.
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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>
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Lu Romero - W4LT

Re: Externmal ATU

In reply to this post by Nr4c

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" <[hidden email]>
Subject: Re: [Elecraft] Externmal ATU
To: <[hidden email]>
Message-ID: <F459B5FC07C34992BDA8A0AA09723477@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

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Joe Subich, W4TV-4

Re: Externmal ATU

In reply to this post by Phil Salas

> 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.

The Quadra uses F-Set for adjusting its internal tuner and is spec'd
to require at least 70W for F-Set to operate. If a "full power" auto-
tuner can't handle 70 Watts while tuning there is a problem.

The K3 should certainly be able to handle a relay-switched tuner on
short-term tuning without a problem ... it certainly does with the
KAT-3.

73,

... Joe, W4TV

On 8/24/2010 11:52 AM, Phil & Debbie Salas wrote:

> "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
>
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
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> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
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>

Phil Salas

Re: Externmal ATU

"The K3 should certainly be able to handle a relay-switched tuner on
short-term tuning without a problem ... it certainly does with the
KAT-3."

I believe that the K3 tunes with low power (5 watts?) when using the KAT3.
The thought of running the K3 at full output into momentary infinite SWR
conditions as autotuner relays switch makes me somewhat uncomfortable.

Phil - AD5X

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Don Wilhelm-4

Re: Externmal ATU

Phil,

I am not certain if you or someone else originally asked the question -
but --
The K3 can provide a lower power RF source for tuning.
As others have mentioned - first set the Tune power in the menu.
Then use TUNE (not ATU TUNE) and the K3 will transmit at the power you
set in the menu.

How you command the tuner to initiate its tune is quite a different
matter. Perhaps RF sensing is appropriate - or one would put the K3
into TUNE and then operate the TUNE button for the tuner.

73,
Don W3FPR

On 8/24/2010 8:56 PM, Phil & Debbie Salas wrote:

> "The K3 should certainly be able to handle a relay-switched tuner on
> short-term tuning without a problem ... it certainly does with the
> KAT-3."
>
> I believe that the K3 tunes with low power (5 watts?) when using the KAT3.
> The thought of running the K3 at full output into momentary infinite SWR
> conditions as autotuner relays switch makes me somewhat uncomfortable.
>
> Phil - AD5X
>

Gary Gregory

Re: Externmal ATU

Or wait for the Elecraft auto-tuner when released in the new year.

Till then use manual mode.

Just my 2cents worth...keep the change...(:-))

Gary

On Wed, Aug 25, 2010 at 11:38 AM, Don Wilhelm <[hidden email]> wrote:

> Phil,
>
> I am not certain if you or someone else originally asked the question -
> but --
> The K3 can provide a lower power RF source for tuning.
> As others have mentioned - first set the Tune power in the menu.
> Then use TUNE (not ATU TUNE) and the K3 will transmit at the power you
> set in the menu.
>
> How you command the tuner to initiate its tune is quite a different
> matter. Perhaps RF sensing is appropriate - or one would put the K3
> into TUNE and then operate the TUNE button for the tuner.
>
> 73,
> Don W3FPR
>
> On 8/24/2010 8:56 PM, Phil & Debbie Salas wrote:
> > "The K3 should certainly be able to handle a relay-switched tuner on
> > short-term tuning without a problem ... it certainly does with the
> > KAT-3."
> >
> > I believe that the K3 tunes with low power (5 watts?) when using the
> KAT3.
> > The thought of running the K3 at full output into momentary infinite SWR
> > conditions as autotuner relays switch makes me somewhat uncomfortable.
> >
> > Phil - AD5X
> >
> ______________________________________________________________
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--
Gary
VK4FD - Motorhome Mobile
http://www.qsl.net/vk4fd/
K3 #679
For everything else there's Mastercard!!!
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Phil Salas

Re: Externmal ATU

In reply to this post by Don Wilhelm-4

"Phil, I am not certain if you or someone else originally asked the
question -
but -- The K3 can provide a lower power RF source for tuning.
As others have mentioned - first set the Tune power in the menu.
Then use TUNE (not ATU TUNE) and the K3 will transmit at the power you
set in the menu."

Don - Yes, I have my TUNE power set for 15 watts (this gives excellant
accuracy with the MFJ-998, and is running the K3 PA at pretty much minimum
power during the tune process). I was commenting on your comment to use the
keying input to tune the radio with a straght key. I currently hit TUNE on
the K3 to start the MFJ-998 tuning process (MFJ-998 is set for full auto and
begins tuning when SWR > 2:1). And while the MFJ-998 disables the amp-key
line during tuning, unless I remember to turn the amp to standby first,
there are a few milliseconds when the amp may be looking at a high SWR
before the MFJ-998 "realizes" the SWR is high, interrupts the amp-key line,
and tunes. My ALS-600 has about 10dB of gain, so with a 15 watt TUNE drive
level I get around 150 watts out. However, a K3 remote input request for
TUNE would eliminate this problem. When you press the TUNE button on the
MFJ-998 it first interrupts the amp-key line, sends a TUNE request to your
transceiver (not currently implemented in the K3, but is in many other
transceivers), tunes, disables the TUNE request, and then re-enables the
amp-key line. Normally my ALS-600 doesn't trip out if I forget to switch it
to standby before pressing TUNE on the K3, but occasionally it does. If the
K3 took in a remote TUNE request, then I would not have to remember to
manually take the ALS-600 off-line.

Phil - AD5X

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Joe Subich, W4TV-4

Re: Externmal ATU

Phil,

> If the K3 took in a remote TUNE request, then I would not have to
> remember to manually take the ALS-600 off-line.

The problem is that the lack of external I/O to accommodate a remote
TUNE request or provide a tune command (e.g., Icom "Start" signal).
It will take some fancy programming - and overloading some of the
existing I/O perhaps with outboard decoding - to accommodate external
tuner control.

73,

... Joe, W4TV

On 8/25/2010 6:43 AM, Phil & Debbie Salas wrote:

> "Phil, I am not certain if you or someone else originally asked the
> question -
> but -- The K3 can provide a lower power RF source for tuning.
> As others have mentioned - first set the Tune power in the menu.
> Then use TUNE (not ATU TUNE) and the K3 will transmit at the power you
> set in the menu."
>
> Don - Yes, I have my TUNE power set for 15 watts (this gives excellant
> accuracy with the MFJ-998, and is running the K3 PA at pretty much minimum
> power during the tune process). I was commenting on your comment to use the
> keying input to tune the radio with a straght key. I currently hit TUNE on
> the K3 to start the MFJ-998 tuning process (MFJ-998 is set for full auto and
> begins tuning when SWR> 2:1). And while the MFJ-998 disables the amp-key
> line during tuning, unless I remember to turn the amp to standby first,
> there are a few milliseconds when the amp may be looking at a high SWR
> before the MFJ-998 "realizes" the SWR is high, interrupts the amp-key line,
> and tunes. My ALS-600 has about 10dB of gain, so with a 15 watt TUNE drive
> level I get around 150 watts out. However, a K3 remote input request for
> TUNE would eliminate this problem. When you press the TUNE button on the
> MFJ-998 it first interrupts the amp-key line, sends a TUNE request to your
> transceiver (not currently implemented in the K3, but is in many other
> transceivers), tunes, disables the TUNE request, and then re-enables the
> amp-key line. Normally my ALS-600 doesn't trip out if I forget to switch it
> to standby before pressing TUNE on the K3, but occasionally it does. If the
> K3 took in a remote TUNE request, then I would not have to remember to
> manually take the ALS-600 off-line.
>
> Phil - AD5X
>
> ______________________________________________________________
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>
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>

Lu Romero - W4LT

Re: Externmal ATU

In reply to this post by Nr4c

I would LOVE to have a Kenwood-AT300-Like press of the ANT
TUNE button on the K3 panel to start an automatic tune
cycle on my K3/ALS600/MFJ998 combo. That would be perfect!

My TUNE POWER is set to 10w. This makes between 40 to 60w
on the ALS600. Using the TUNE press and hold method, the
tuner sort of "snaps" the needed values in in less than a
second, everywhere I go. Again, I have taught the tuner my
antennas and memorized them into the tuner memory ahead of
time. The amp is interupted, the tuner tunes, then the amp
is re-enabled, and the power then goes up from 10w to the
above values. The red light on the amp sort of blinks.

Interesting that Phil's '998 takes a while to figure things
out.

I bought my ALS600/MFJ998 combo after reading Phil's review
of the system... Could it be a '998 firmware thing?

-lu-w4lt-

Message: 15
Date: Thu, 26 Aug 2010 17:07:12 -0400
From: "Joe Subich, W4TV" <[hidden email]>
Subject: Re: [Elecraft] Externmal ATU
To: [hidden email], [hidden email]
Message-ID: <[hidden email]>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

Phil,

> If the K3 took in a remote TUNE request, then I would not
have to
> remember to manually take the ALS-600 off-line.

The problem is that the lack of external I/O to accommodate
a remote
TUNE request or provide a tune command (e.g., Icom "Start"
signal).
It will take some fancy programming - and overloading some
of the
existing I/O perhaps with outboard decoding - to accommodate
external
tuner control.

73,

... Joe, W4TV

On 8/25/2010 6:43 AM, Phil & Debbie Salas wrote:
> "Phil, I am not certain if you or someone else originally
asked the
> question -
> but -- The K3 can provide a lower power RF source for
tuning.
> As others have mentioned - first set the Tune power in the
menu.
> Then use TUNE (not ATU TUNE) and the K3 will transmit at
the power you
> set in the menu."
>
> Don - Yes, I have my TUNE power set for 15 watts (this
gives excellant
> accuracy with the MFJ-998, and is running the K3 PA at
pretty much minimum
> power during the tune process). I was commenting on your
comment to use the
> keying input to tune the radio with a straght key. I
currently hit TUNE on
> the K3 to start the MFJ-998 tuning process (MFJ-998 is set
for full auto and
> begins tuning when SWR> 2:1). And while the MFJ-998
disables the amp-key
> line during tuning, unless I remember to turn the amp to
standby first,
> there are a few milliseconds when the amp may be looking
at a high SWR
> before the MFJ-998 "realizes" the SWR is high, interrupts
the amp-key
line,
> and tunes. My ALS-600 has about 10dB of gain, so with a
15 watt TUNE drive
> level I get around 150 watts out. However, a K3 remote
input request for
> TUNE would eliminate this problem. When you press the
TUNE button on the
> MFJ-998 it first interrupts the amp-key line, sends a TUNE
request to your
> transceiver (not currently implemented in the K3, but is
in many other
> transceivers), tunes, disables the TUNE request, and then
re-enables the
> amp-key line. Normally my ALS-600 doesn't trip out if I
forget to switch it
> to standby before pressing TUNE on the K3, but
occasionally it does. If the
> K3 took in a remote TUNE request, then I would not have to
remember to
> manually take the ALS-600 off-line.
>
> Phil - AD5X

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Chuck - AE4CW

Re: Externmal ATU

I bought my ALS600/MFJ998 combo after reading Phil's review
of the system... Could it be a '998 firmware thing?

-lu-w4lt-

MFJ released a new Firmware for the MFJ-998 dated 08/02/2010. See here:

http://www.mfjenterprises.com/support.php?productid=MFJ-998

Chuck, AE4CW

---
Chuck, AE4CW

Phil Salas

Re: Externmal ATU

"...MFJ released a new Firmware for the MFJ-998 dated 08/02/2010. ..."

The MFJ-998 wasn't interrupting the amp-key line when it tuned from memory.
I guess it was assumed that this happend very quickly so this would not
cause a problem. However, as the relays operate you can have a momentary
high VSWR condition. So this will help. HOWEVER - it takes a finite period
of time for the tuner to "decide" that the VSWR is high and to measure the
incoming frequency. So during this "decision" process (when you change
bands or antennas), you could have a high VSWR presented to the amplifier
before the amp-enable line is interrupted and the new tuner values are
snapped in place. There are four ways around this:

1) With the tuner in full auto, flip the amp to standby and hit TUNE on the
K3 when you change bands/antennas. If the VSWR is greater than the MFJ-998
programmed "start tuning" value, the tuner will tune. Then flip the amp to
operate. This is what I do now (K3 tune output set for 15 watts).
2) Provide band data to the tuner so it tracks band changes before you even
transmit. Not supported by the current MFJ-998. And this requires more
untelligence if you have more than one antenna/band.
3) Leave the tuner in manual mode and press TUNE on the tuner when you
change bands or antennas. This interrupts the amp-key line before tuning
starts. But this requires a TUNE REQUEST input to the K3 which is not
available.
4) Use resonant antennas on all bands and forget the tuner!

Phil - AD5X

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