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question re K3's KAT3 ATU

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Kate Hutton

question re K3's KAT3 ATU

I am often on the same frequency daily - 3.575 MHz, but the ATU does not
give me exactly the same answer every night. On my wire antenna it always
starts at 5.8:1 to 6.1:1 and ends up at 1.8:1 or 1.7:1. But sometimes, it
gives me 1.0:1. The power shown on the display when transmitting always
seems to be more or less what I set it for. What is causing this
inconsistency & is it a problem?

Thanks,
73 Kate K6HTN
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Guy, K2AV

Re: question re K3's KAT3 ATU

Depending on your antenna, the answer can be as simple as ground
moisture. Would need more detail about your antenna to speculate
farther. 73, Guy.

On Mon, Jun 27, 2011 at 10:12 PM, Kate Hutton <[hidden email]> wrote:

> I am often on the same frequency daily - 3.575 MHz, but the ATU does not
> give me exactly the same answer every night. On my wire antenna it always
> starts at 5.8:1 to 6.1:1 and ends up at 1.8:1 or 1.7:1. But sometimes, it
> gives me 1.0:1. The power shown on the display when transmitting always
> seems to be more or less what I set it for. What is causing this
> inconsistency & is it a problem?
>
> Thanks,
> 73 Kate K6HTN
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

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wayne burdick

Re: question re K3's KAT3 ATU

Administrator

In reply to this post by Kate Hutton

It's not a problem, but I can probably improve this behavior in K3
firmware. It's on my list.

73,
Wayne
N6KR

On Jun 27, 2011, at 7:12 PM, Kate Hutton wrote:

> I am often on the same frequency daily - 3.575 MHz, but the ATU does
> not
> give me exactly the same answer every night. On my wire antenna it
> always
> starts at 5.8:1 to 6.1:1 and ends up at 1.8:1 or 1.7:1. But
> sometimes, it
> gives me 1.0:1. The power shown on the display when transmitting
> always
> seems to be more or less what I set it for. What is causing this
> inconsistency & is it a problem?
>
> Thanks,
> 73 Kate K6HTN
> ______________________________________________________________
> Elecraft mailing list
> Home: http://mailman.qth.net/mailman/listinfo/elecraft
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:[hidden email]
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html

Matt Zilmer

Re: question re K3's KAT3 ATU

In reply to this post by Kate Hutton

Push the ATU TUNE button once to get a quick but somewhat rough SWR
match. If you push ATU TUNE a second within 5 seconds of the first
pass completing, the ATU will take more time and come up with a better
SWR match.

Your antenna may have some wind on it, and this can affect SWR
consistency. Rain on ladder line does the same thing.

None of this is a problem, as long as your SWR matches 2.0:1 or less.
The K3's PA and protection circuitry work very well into imperfect
loads. The PA is *very* robust and well-tested for odd loads.

We had a balky 65 foot dipole during Field Day this year, where the
ATU TUNE SWR showed 1.5:1. When we put full power into the load,
during long term CW ops it showed 2.5:1. With 95W showing on the
external LP100 meter, we just kept on truckin' - for seven more hours
until the sun showed its face around 5:10 AM or so. My K3 survived
all that. I've seen it take on considerably worse SWR and handle the
situation just fine.

73,
matt W6NIA

==

On Mon, 27 Jun 2011 19:12:16 -0700, you wrote:

>I am often on the same frequency daily - 3.575 MHz, but the ATU does not
>give me exactly the same answer every night. On my wire antenna it always
>starts at 5.8:1 to 6.1:1 and ends up at 1.8:1 or 1.7:1. But sometimes, it
>gives me 1.0:1. The power shown on the display when transmitting always
>seems to be more or less what I set it for. What is causing this
>inconsistency & is it a problem?
>
>Thanks,
>73 Kate K6HTN
>______________________________________________________________
>Elecraft mailing list
>Home: http://mailman.qth.net/mailman/listinfo/elecraft
>Help: http://mailman.qth.net/mmfaq.htm
>Post: mailto:[hidden email]
>
>This list hosted by: http://www.qsl.net
>Please help support this email list: http://www.qsl.net/donate.html

DK4XL

Re: question re K3's KAT3 ATU

In reply to this post by wayne burdick

Hi Wayne,

would you tell us what else is on this (your) list ? :-)

Martin

Kate Hutton

Re: question re K3's KAT3 ATU

In reply to this post by Kate Hutton

Thanks all. I think the answer to my question was the one about whether it
is in "course" or "fine" tuning mode.

73 Kate K6HTN

On Mon, Jun 27, 2011 at 7:12 PM, Kate Hutton <[hidden email]> wrote: