[Elecraft] KAT500 Tuning issue

[Jerry Weisskohl]

Mark,
Thanks for the reply. I received quite a few replies pointing out exactly
what you said. Because it wouldn't load on 20 meters I was using my other
antenna, which works fine with the KAT500 (80 meter vertical). However, I
was trying to understand why the 40 meter dipole wasn't working well on 20
and I thank all those that replied. This reflector is a wealth of
knowledge! Now I realize my KAT500 is working as it should. Having two
antennas comes in handy!

Thanks,

Jerry - AC4BT


On Sat, Dec 8, 2012 at 5:49 PM, Mark Bayern <plcmark at gmail.com> wrote:

> Just to make sure we're all on the same page ...
>
> When the tuner (at the radio) gets an acceptable match, that just
> means the transmitter will _think_ there is a good antenna system out
> there. The feedline between the antenna and the tuner will know
> otherwise and can have points of very high voltage that could cause
> insulation breakdown, and points of very high current that can cause
> overheating and will be a source of power loss. This isn't really a
> problem in QRP operations, but when you head into the QRO world it can
> make a difference. The antenna also has issues. In an earlier post
> K3KO had the calculated feedpoint impedance, and it was very far from
> the 'nominal' 50 ohms of your feedline or the ~75 ohms of a dipole at
> altitude. W6GF also gave this info in terms of SWR to show how bad it
> was. All in all a resonant 40M dipole makes an unhappy antenna system
> on 20 meters.
>
> I understand that if that is all you have you're stuck with it, but it
> is really time to consider something else. Maybe a fan dipole, or trap
> dipole?
>
> Mark AD5SS
>
>
>
> On Sat, Dec 8, 2012 at 3:30 PM, Jerry Weisskohl <jweisskohl at gmail.com>
> wrote:
> > Right now, I have the coax from the antenna directly connected to the
> > KAT500. I could try using my Delta-4 switch, have the coax go to that and
> > then a small run to the KAT500 to see if that makes a difference. The
> high
> > swr is an issue on 40 and 10 meters, however, ten is manageable, it's
> about
> > 1.9 - 1 and I am working around the issue but using my 80 meter vertical
> on
> > 20 meters. So this is not a "show-stopper" but just wanted to understand
> >  why it was happening.
> >
> > Jerry - AC4BT
> >
>