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K2 has one freq with low swr - all others fine - what to check

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Tim Logan

K2 has one freq with low swr - all others fine - what to check

Hi all -
I have a K2 connected to a separate KPA/100 - KAT/100 box. Any frequency
on my rig will tune with an SWR of 1.5 or less EXCEPT in the 7.200 MHz
area where it only hits about 3.7 - 1.0. It seems odd to me that only
such an isolated freq range would do this....so it makes me wonder if
there is something within the rig I need to check.....vrs blaming it on
my wire loop which has served me so well.

Being a guy whose highest technical acheivement is turning on a
soldering iron - I would like a suggestion for where to start and how to
proceed checking out my rig for this particular issue. Could someone
offer a suggestion? Thanks very much in advance.

73/ Tim, NZ7C
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Dan Barker

RE: K2 has one freq with low swr - all others fine - what tocheck

Change the length of the feedline by a few feet. See if the problem can be
"encouraged" to move outside the ham bands.

Dan / WG4S / K2 #2456

<snip>
is something within the rig I need to check.....vrs blaming it on my wire
loop which has served me so well.
</snip>

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Don Wilhelm-3

RE: K2 has one freq with low swr - all others fine - what tocheck

In reply to this post by Tim Logan

Tim,

It is likely that your feedline is presenting a very high impedance at that
frequency. The Elecraft tuners do not like to tune high impedances very
well - OTOH, they do not usually have a problem with low impedances.

Try adding about 25 feet of feedline - if the KAT100 then is able to tune
it, you will know that the antenna is truly presenting a high impedance at
the shack end. You can either adjust the antenna or the feedline length
until it tunes on all bands of interest.

73,
Don w3FPR

> -----Original Message-----

>
> Hi all -
> I have a K2 connected to a separate KPA/100 - KAT/100 box. Any frequency
> on my rig will tune with an SWR of 1.5 or less EXCEPT in the 7.200 MHz
> area where it only hits about 3.7 - 1.0. It seems odd to me that only
> such an isolated freq range would do this....so it makes me wonder if
> there is something within the rig I need to check.....vrs blaming it on
> my wire loop which has served me so well.
>
> Being a guy whose highest technical acheivement is turning on a
> soldering iron - I would like a suggestion for where to start and how to
> proceed checking out my rig for this particular issue. Could someone
> offer a suggestion? Thanks very much in advance.
>
> 73/ Tim, NZ7C
>

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Tim Logan

Re: K2 has one freq with low swr - all others fine - what tocheck

In reply to this post by Dan Barker

Yep that appears to have done it - thanks Dan - and thanks Don!
73/Tim

Dan Barker wrote:

>Change the length of the feedline by a few feet. See if the problem can be
>"encouraged" to move outside the ham bands.
>
>Dan / WG4S / K2 #2456
>
><snip>
>is something within the rig I need to check.....vrs blaming it on my wire
>loop which has served me so well.
></snip>
>
>_______________________________________________
>Elecraft mailing list
>Post to: [hidden email]
>You must be a subscriber to post to the list.
>Subscriber Info (Addr. Change, sub, unsub etc.):
> http://mailman.qth.net/mailman/listinfo/elecraft
>
>Help: http://mailman.qth.net/subscribers.htm
>Elecraft web page: http://www.elecraft.com
>
>
>