Hello, again, all.

 

Well, my Alpha Delta DX CC antenna is  finally up out here at the RV camp
site.

 

It is up a good 30 feet in the trees, with the  center and ends being at
about the same height.

 

I have done some preliminary testing of the antenna, and all looks good,
with one exception.

 

Specifically, the antenna tunes with the TS480 internal auto-tuner across
the 10, 15, and 40-meter bands.  It even tunes across much of 80 meters,
from about 3600 to about 3900 KHZ.

 

However, I cannot get it to tune at all on 20 meters, once again, using the
TS480 internal auto tuner.  I even put my MFJ auto-tuner extender in line,
with no luck.

 

This is a bit disappointing to me, since 20 meters is one of my favorite
field day operating bands.

 

As I am scratching my head here to try to determine what might be going on,
I have two theories.  First, it has to be understood that I am limited to
keeping the antenna within my lot space, and have to work with the available
trees.  This means that the legs of the antenna are probably only about at a
60-degree or so angle from the center.  In other words, the antenna is kind
of like a folded  dipole in some ways.  I wonder if this could be de-tuning
the antenna on 20, although I'm not sure why it also would not bbe de-tuning
it on the other bands I mentioned.

 

My second theory has to do with my coax feed line.  It turns out that I
probably have about 40 extra feet of coax that I have coiled up underneath
my station operating area.  I wonder too if this might have something to do
with the strange 20-meter behavior.

 

Obviously, I'm happy that the antenna is usable on 10, 15, 40, and 80, so
I'm sure I'll have a good Field Day exxperience.  But, the 20-meter problem
does puzzle me.

 

Does anyone have any thoughts, or suggestions that I might try to get things
working on 20 meters?

 

Tom Behler: KB8TYJ