[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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