[UK-CONTEST] Inverted V help

john lemay john.lemay at which.net
Tue Feb 18 07:34:26 EST 2003


Hello all

In one of my very rare forays below 50MHz, I decided to try an inverted V
for 80m. It would use my modest Versatower for the central support, and the
ends would end up where-ever.

I knew it would be a compromise :-

I probably could not get enough height
I probably could not get the right apex angle
One end in particular would need to be close to the house and bent through
90 degrees
The other end would be in trees.

Even so, I thought that at least I would get an antenna that would be within
the limits of a typical internal ATU on my rig.

Wrong !

It received quite well, and nicely quiet compared to my HF6V. But the match,
checked out on the MFJ analyser was about 10 to 1. I have done the obvious
tests, such as continuity of wire, continuity through balun etc.

Today, I have taken down the 1:1 balun (Watson) and checked it out with a
resistor across the terminals. Interesting: - Using a 50ohm resistor which
is suitable for low frequency rf use, the match through the balun at 3.0MHz
is about 2 to 1. It gets worse going lf, and improves to 1.2 to 1 by about
10MHz. Then not surprisingly above 40MHz the match gets lots worse.

What I need help in deciding, is whether my abysmal match with something
resembling an inverted V is due to too many antenna compromises or is it due
to a dodgy balun ? (Preferably without too many more sessions freezing in
the garden, or hauling the tower up and down).

Regards

John G4ZTR






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