Topband: Shunt feeding the Skyneedle

[Tom W8JI]

the vertical section was still suppressed and the top 29' was resonating. 
With this in mind I decided to run a shunt wire from the top to see where 
the antenna resonates.  Here's what I found..>>>>

I was afraid the tower was messing up the L. This is what happens when they 
are are nearly resonant.

You can't measure tower resonance with a drop wire. The drop wire is a stub 
or shorted transmission line in parallel with the common mode impedance 
presented by the drop wire and tower combination. It is just a mess of stuff 
going on.

 <<<
The MFJ read 380 ohms at 1825 and the X is way off the scale.  I inserted an 
EF Johnson 10-160pf air variable capacitor at the base.in series.and was 
able to tune the antenna to 60 ohms and the X=22.  If I played with the cap 
there was a real sharp drop in reactance showing X=12.  The air variable was 
about ¾ meshed.>>>



Reducing the lenth (tap point height) of the drop wire is a better way to 
get impedance right. Or, better still, use a multiple wire drop to make the 
drop diameter look larger. That will reduce Q, require more C, and should 
reduce impedance.

You are so close at 60 ohms I would not worry. Adjust the cap for lowest 
SWR. What is the SWR??