Re: K3 Internal Tuner Question

Posted by Joe Subich, W4TV-4 on Jan 02, 2012; 4:56pm
URL: http://elecraft.85.s1.nabble.com/K3-Internal-Tuner-Question-tp7143025p7144264.html


> You didn't say how much coax ran from the K3 to the Palstar. For an
> accurate comparison it should be zero (use an adapter) or at most an
> couple of inches of coax.

It the KAT3 is in use one can *never* compare the SWR displayed by the
K3 and that displayed by an external SWR bridge/wattmeter since there
will be an *impedance changing device* (the KAT3) between the K3's SWR
detector and the external SWR detector even if the length of coax is
zero.

73,

    ... Joe, W4TV


On 1/2/2012 11:27 AM, Ron D'Eau Claire wrote:

> John, that is a common question.
>
> The KAT3 is providing a 1:1 SWR between the KAT3 and the PA *inside* the K3
> so the K3's PA is 'seeing' the correct load. The KAT3 cannot change the
> impedance of the antenna presented to the ANT connector.
>
> You didn't say how much coax ran from the K3 to the Palstar. For an accurate
> comparison it should be zero (use an adapter) or at most an couple of inches
> of coax.
>
> You can replace the antenna with a good dummy load, and they should read
> much closer, although most dummy loads have some error as well, nor are SWR
> meters precision instruments; they don't need to be for efficient
> transmission line operation at H.F.
>
> Ron AC7AC
>
>
> -----Original Message-----
> From: [hidden email]
> [mailto:[hidden email]] On Behalf Of John Dziedziejko
> Sent: 02 January 2012 04:13
> To: [hidden email]
> Subject: [Elecraft] K3 Internal Tuner Question
>
> I installed the KAT3 over the weekend and the construction and calibration
> was successful. This evening I hooked everything back up to check reception,
> tuning and swr. I have it set to AUTO, when I tap the ATU TUNE switch the
> tuner does its thing and I read a 1.0:1 swr on the K3 meter. I have a
> Palstar Wattmeter installed between the K3 and the antenna and for some
> reason I am getting a high swr on the Palstar meter of 5:1 and don't
> understand why. I have a multiband vertical antenna with a 4:1 Unun at the
> base of the antenna. Am I missing something here?
>
> A little hand holding would be appreciated.
>
> Regards,
>
> John W9QP
>
>
>
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