[Mldxcc] Fixed - but why?

[Emileigh Starbrook]

I found the solution to the height issue and the answer is more confusing
than ever.  Some history first.  Originally I had been feeding the antenna
with a 75' piece of LMR-400UF to the base, then 20' of LMR-400UF to the
balun mounted at the dipole.  The system was working flawlessly. However, I
was nervous about the wear and tear (and weight) of the LMR-400 on the
connector at the top so I replaced it with a brand new 20' length of
LMR-240UF - since this is HF - not much difference in the loss. Oh - the
reason for the two lengths of coax is so I can put the antenna analyzer on
it to retune it whenever I change bands.

After watering the ground, dismantling the antenna, cleaning every piece,
re-assembling it, moving it to the other side of the yard as far away from
the house as I could get,  and finally replacing the feedline with another
(50') piece of LMR-240UF, the results were all the same - no change.

I went back to the books and started looking at more than SWR.  The
MFJ-259C measures R,X,Z and phase angle.  What I found was that when
feeding it with either piece of LMR-240 (25 or 50') there was a very
curious change.  The measured phase angle was changing. Depending on the
height it could be 30, 0, 10 or 18 degrees - 0 happening at that shortened
height where the SWR was lowest.

This was new to me, so finally I went and got the old piece of LMR-400 and
measured with it.  What I found was the phase angle was always zero and the
problem was solved - the higher the antenna, the lower the SWR.

So I have no idea why that would make such a big difference.  Any comments
would be most welcome.

Emi


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"There are two ways to be fooled.  One is to believe what isn't true; the
other is to disbelieve what is true."
- Soren Kierkegaard

Three - watch Fox News.
- Emily Clarke