[Elecraft] Using the K3s Tune button causes a growing SWR on my KPA500

Dave Erickson radio at disseminator.net
Fri Jul 15 23:39:34 EDT 2022


On 7/15/2022 10:35 PM, Peder Kittelson wrote:
> That is a good question.  I was thinking of adding to the answer above.  
> I called Palstar about a year ago and asked if there was any problem 
> linking a coax cable through a short length of balanced line.  He said 
> he did not see any problem with that.  So I have used the tuner that way 
> and until now have not had any problem with it that I have noticed.  It 
> is unusual to be sure.
> 
> Thanks again for your help,
> 
> Peder
> 
> On Fri, Jul 15, 2022 at 8:28 PM Dave Erickson <radio at disseminator.net 
> <mailto:radio at disseminator.net>> wrote:
> 
>     On 7/15/2022 10:21 PM, Peder Kittelson wrote:
>      > The antenna is homemade, in a sense.  I bought a 9-1 Balun from
>     Balun
>      > Designs with the capacity for a tie into a counterpoise which I
>     use.  I
>      > have a 30 DB inline RF attenuator attached to the Balun Designs
>     piece.
>      > I have run RG213 to my radio room.  I have a separate Palomar 9-1
>     Un-Un
>      > in the line near my equipment.  The EFHW transmission wire is 53
>     feet
>      > long.  A length recommended for multiband EFHW wires.  That
>     length has
>      > no natural resonance which would cause problems, according to the
>     charts
>      > I have seen.
>      >
>      > Thank you for your thoughts
>      >
>      > Peder
>      >
>      > On Fri, Jul 15, 2022 at 8:07 PM Dave Erickson
>     <radio at disseminator.net <mailto:radio at disseminator.net>
>      > <mailto:radio at disseminator.net <mailto:radio at disseminator.net>>>
>     wrote:
>      >
>      >     On 7/15/2022 9:53 PM, Peder Kittelson wrote:
>      >      > When on 80 meters, the longer I hold the tune button down the
>      >     higher the
>      >      > SWR goes to the point the KPA500 folds back with warnings.  I
>      >     don't usually
>      >      > hold down the tune button longer than about 5-6 seconds.
>      >      >
>      >      > I use a Manual Palstar BT1500A tuner which does a good job of
>      >     tuning my
>      >      > EFHW wire antenna.  So the initial tune is very good. I
>     sometimes
>      >     will hold
>      >      > down the Tune button on the K3s for maybe 5-6 seconds with the
>      >     initial tune
>      >      > at 1-1 SWR.
>      >      >
>      >      > The KP500 first shows a 1-1 SWR.  Then 1.2-1, 1.3-1 and so
>     on.  I
>      >     stop when
>      >      > it reaches 1.5-1.
>      >      >
>      >      > I suppose that initially the transmitting wire sends out the
>      >     signal and
>      >      > over time the current backs up.  I have torroids in place to
>      >     prevent RFI
>      >      > coming back down the antenna transmission line.
>      >      >
>      >      > I only use the system for CW.  So when I send, the problem
>     does not
>      >      > escalate to the point of a dangerous SWR.
>      >      >
>      >      > I wonder if this is a normal problem when holding the
>     tuning button
>      >      > longer?  And since I do not hold down the key for a long
>     period
>      >     of time it
>      >      > doesn't develop.
>      >      >
>      >      > Still, I am looking at solutions. And I am concerned.
>      >      >
>      >      > Your thoughts?
>      >      >
>      >
>      >     Hi,
>      >
>      >     Are you feeding an EFHW antenna with balanced feed-line? I don't
>      >     believe
>      >     I have seen that done much.
>      >
>      >     Is your antenna commercial or home made? I'd like to see more
>     about
>      >     that.
> 
>     Peder,
> 
>     I am a little confused I guess, but how does this antenna system work
>     with the Palstar BT1500A which only has connections for balanced
>     feed-line?
> 
>     There is a lot going on there I think.

Peder,

That is a fairly unique arrangement to be sure.

Good Luck, I hope you find the answer.

-- 
Dave Erickson
AB0R
73



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