KAT3 tuning per Antenna

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KAT3 tuning per Antenna

Greg - AB7R
On Thursday a few people asked if the KAT3 tuner could be on AUTO for one
antenna and bypassed for the other.

At present it is global.  But it is high on the firmware list to be changed
so the tuner state is per antenna.  Its not likely to be done prior to first
shipment, but will not be long after.



------------
73,
Greg - AB7R
Whidbey Island WA



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Re: KAT3 tuning per Antenna

Don Wilhelm-4
Greg,

If one of the outputs is tuned into a 50 ohm resistive load, it is
effectively bypassed.  I just don't understand the real need for a
bypass and consider it a 'nicety'.  Like if ANT2 has a resonant
multiband antenna connected, just tune it once on each band and you are
ready to go.

Perhaps someone can enlighten me about the utility of a true bypass
function.

73,
Don W3FPR

Greg wrote:
> On Thursday a few people asked if the KAT3 tuner could be on AUTO for one
> antenna and bypassed for the other.
>
> At present it is global.  But it is high on the firmware list to be changed
> so the tuner state is per antenna.  Its not likely to be done prior to first
> shipment, but will not be long after.
>
>  
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Re: KAT3 tuning per Antenna

Vic K2VCO
Don Wilhelm wrote:

> If one of the outputs is tuned into a 50 ohm resistive load, it is
> effectively bypassed.  I just don't understand the real need for a
> bypass and consider it a 'nicety'.  Like if ANT2 has a resonant
> multiband antenna connected, just tune it once on each band and you are
> ready to go.
>
> Perhaps someone can enlighten me about the utility of a true bypass
> function.

Setting the tuner to a 50 ohm load is a better way of 'bypassing' it
than removing all the autotuner's capacitors and coils from the circuit
(which is what 'bypass' does).

Because there is some stray capacity/inductance in the board and
connections, tuning it into a dummy load cancels this out.

There was a lot of discussion on the beta test reflector about this.
It's possible that Wayne will either make bypass work per-band, or (as I
prefer) make it set the tuner (per band) to match a 50 ohm load.

Meanwhile, I just connect my dummy load and tune it (and of course the
tuner remembers the settings per band) if I want to 'bypass' the tuner
on a particular band or bands.
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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Re: KAT3 tuning per Antenna

M0XDF
In reply to this post by Don Wilhelm-4
I have an external SGC to a long wire, it tunes up on every band. I plan on
putting up some form of non-specific dipole so I only need to tune that.
Apart from not knowing if the KAT3 could handle the long wire, the tuner is
external to keep the RF out the shack. Therefore I would like to be able to
control tuning on the ANTs independently.


On 23/9/07 05:30, "Don Wilhelm" <[hidden email]> sent:
> Perhaps someone can enlighten me about the utility of a true bypass
> function.
--
Always remember, half the people in the world are above average
intelligence!


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Re: KAT3 tuning per Antenna

M0XDF
In reply to this post by Vic K2VCO
I might have missed something - the KAT3 will remember its setting per ANT
socket?
But how do you stop it attempting to tune again - maybe one just doesn't
worry about it.

> Setting the tuner to a 50 ohm load is a better way of 'bypassing' it
> than removing all the autotuner's capacitors and coils from the circuit
> (which is what 'bypass' does).

--
I know that you believe that you understood what you think I said, but I am
not sure you realize that what you heard is not what I meant.
-- Robert McCloskey, State Department spokesman (attributed)


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Re: KAT3 tuning per Antenna

Tom Hammond-2
Hi David:

The KAT3 will NOT re-tune unless you TELL it to do so!

When changing from one band/antenna to another, the KAT3 will select
the last-used
L-C set for that band/antenna and use that set unless you press the [ATU TUNE]
button to force it to retune.

So, assuming you have already (previously) told the KAT3 to select a set of L-C
values for a band AND for a certain antenna (connected to ANT1 or ANT2) then
going back to that band and antenna selection will result in the KAT3 choosing
the last-used (supposedly suitable) set of values.

If you have two different antennas (connected to ANT 1 _and_ ANT2) and EITHER
of these antennas can be used on a certain band (say both a vertical
and a dipole,
capable of operation on 40M), then the KAT3 will remember the L-C
values used for
EACH antenna and they will be selected FOR that antenna (whichever antenna is
selected) when you switch to 40M.

73,

Tom   N0SS

At 03:12 09/23/2007, David Ferrington, M0XDF wrote:

>I might have missed something - the KAT3 will remember its setting per ANT
>socket?
>But how do you stop it attempting to tune again - maybe one just doesn't
>worry about it.
>
> > Setting the tuner to a 50 ohm load is a better way of 'bypassing' it
> > than removing all the autotuner's capacitors and coils from the circuit
> > (which is what 'bypass' does).
>
>--
>I know that you believe that you understood what you think I said, but I am
>not sure you realize that what you heard is not what I meant.
>-- Robert McCloskey, State Department spokesman (attributed)
>
>
>_______________________________________________
>Elecraft mailing list
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>
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Re: KAT3 tuning per Antenna

Vic K2VCO
In reply to this post by M0XDF
David Ferrington, M0XDF wrote:

> I might have missed something - the KAT3 will remember its setting per ANT
> socket?

Yes.

> But how do you stop it attempting to tune again - maybe one just doesn't
> worry about it.

It only tunes if you press TUNE. Wayne has said that he might add some
more complicated optional behavio(u)r in the future, but for now it
tunes when you tell it to. Of course when you change bands or antennas
it switches to whatever it has saved for that band/antenna combination.

This is exactly how the KAT2 and KAT100 work (except they do not have an
explicit bypass setting).
--
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco
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Re: KAT3 tuning per Antenna

Don Wilhelm-4
In reply to this post by M0XDF
David,

It still works the same - tune the KAT3 (or KAT2) output that is to
connect to the autotuner into a dummy load on each band.  Thereafter, do
not press TUNE when that antenna is selected.
If you need to provide RF to tune the external autotuner, reduce the
power if necessary and press the key.

I guess there is utility for a bypass mode on one antenna port for those
who use an external autotuner which requires RF power for tuning, but I
cannot think of any other instance.

73,
Don W3FPR

David Ferrington, M0XDF wrote:
> I have an external SGC to a long wire, it tunes up on every band. I plan on
> putting up some form of non-specific dipole so I only need to tune that.
> Apart from not knowing if the KAT3 could handle the long wire, the tuner is
> external to keep the RF out the shack. Therefore I would like to be able to
> control tuning on the ANTs independently.
>
>  
>
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