In message , Andy
writes

"Ian Jackson" wrote in message
...

Anyway, it's interesting what you have found out with the dipole
configuration. Presumably, you still have the coax braid and one side of
300 ohm feeder earthed. If so, I would not have expected there to be quite
such a dramatic change of resonance. However, if your earth rods are
totally ineffective (or you have disconnected the earth), you might expect
things to change a lot when you add 'the other half of the dipole'. If you
actually have room to put up an appx 60 foot + 60 foot dipole, why not
consider a G5RV (which, I believe, you have already tried) or a W3DZZ trap
dipole? This would get rid of your earthing problems.
--
Ian


How I got the extra 60 feet + up was to bring it back on itself towards the
house in a shape of the letter V. The wire is very low to the floor and in
every ones way. I have no idea how it radiates in this shape. It can only be
like this as a temp solution.
I really need to understand why the End Fed wire is behaving the way it
does. I think the Analyser is working OK or it wouldn't be able to tune a
Centre Fed Dipole. I hope

When the earth rod was connected to the End Fed wire as a ground, there was
a definite 2 S points up on received signal compared to it being
disconnected. So it must be doing something.

True.

I had a listen around 2 - 3.5 MHz for any strong signals and I can't find
any that might cause me problems.

Noted.

I would have expected the frequency to change when altering the length of
the wire.

73 Andy.

What you have done is essentially to add a counterpoise / radial which
is appx a quarterwave long. This is really the other half of the dipole.
The higher it is up in the air, the more it will radiate. Note that, as
it is at the top end of the 15 feet of 300 ohm feeder, the feeder will
act like a transformer, and couple RF into 'counterpoise'. The
'counterpoise' will be more lively than if it were connected to the
braid at the far end of the coax.

As the 'counterpoise' is coming back under the actual aerial wire
(albeit at an angle) the radiation will tend to oppose that from the
aerial. This will reduce the overall radiation, so the greater the
separation, the better.

[Of course, if the counterpoise can be run in the opposite direction
from the aerial wire, the radiation doesn't cancel, and you might as
well erect the counterpoise as high as possible. What you will have, of
course, is a 'normal' dipole.]

I still think all of this points to the fact that your earth rods are
making very poor contact with the ground. If you have a fantastic earth
connection, counterpoises and radials have little effect. With an
absolutely lousy ground contact (and poor ground conductivity), they can
make a great difference. With the single wire (and no counterpoise), the
analyser will need a good earth connection. Without it, it's going to
read rubbish, which may explain why a change of wire length makes no
difference.

I think I would concentrate on improving the ground connection a bit
more (more earth rods, or maybe some wires buried in the ground?). My
inverted-L aerial feed is at the fence at the end of my back garden. The
earthing system (at the fence) consists of three old bits of galvanized
water pipe (about 6 foot long), and each about 6 feet apart. In addition
to that, the wooden fence posts are mounted into 'Metposts'
http://www.metpost.co.uk/
each of which is about around 2.5 foot long, with only about 6 inches
above the ground. The length of the fence is 70 feet, so there about
Metposts. Most of these are also connected to my earthing system. I did
once try adding a counterpoise for 80m, but it had no effect. [My soil,
by the way, is mainly clay and flints. That which is not, is old
bricks.]

When you've done as much as is reasonable with you earth system, all you
can do is to add counterpoises etc.

If you really cannot get an efficient earth/counterpoise system, you
will probably be better concentrating your efforts on dipoles (even if
you have to use bent or compressed versions). At least you know where
you are with a dipole.
--
Ian