wrote in message
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826,
My first thought is that the feed line has become 'part' of the
antenna and has changed the antenna's characteristics accordingly. My
second though, if that 6 foot of feed line was connected directly to
the antenna when measurements were taken, is that you being that close
to the antenna changed it's characteristics.
So, what to do? How about doing that checking from the end of the
feed line that will normally be used? Make any antenna adjustments
accordingly. Don't want that feed line to be 'part' of the antenna?
Well, how about using a feed line to do the checking that's of an
appropriate length to sort of 'cancel' it's self out, to do the
checking?
Doing all that checking will also give you some idea as to the
accuracy of your measuring device, and the characteristic values of
the feed lines, etc, sort of.
That's the 'long' version. The 'short' version is that you're
probably doing something wrong, re-do it.
- 'Doc

Not much of an answer, huh?


Surprise!

It is turning out that coax isn't what you thought it was, is it?

Lots of folks think that coax is some miracle device that absolutely
contains all of the RF until the RF reaches (poetic license please) the
termination point. In truth, no such creature exists in any form of
transmission line.

What you are trying to do is to make the transmission line the worst
possible radiator and the antenna the best possible radiator. There are
gazillions of possibilities somewhere betwen those two potentials.

Run the full length of transmission line into your shack and then tune the
antenna based upon the data gathered in the shack. Yes, it is a PITA, but it
is the only way to do it, if you want the best tuning.

Every antenna system is just that, a system. It cannot be tuned piecemeal to
obtain the best end result. Welcome to the world of radio.

Oh, it isn't so bad once you get used to it. Now you have an excuse to
invite a ham over to help you by reading the analyzer while you are outside
making adjustments to the antenna.

Wait until you discover, if you haven't already, that adjusting one part of
the antenna will cause you to readjust another part of the antenna, probably
the one that you adjusted before the last part that you adjusted. Hang in
there. It is doable. Good luck with your project.

Jack