advice needed as to G5RV 160m use
 

I am using the MFJ G5RV, and have a coil of coax for balun purposes between
the ladderline and coax to the shack. My G5RV works fine.

Now, I'm starting to think about using it on 160m, as the MFJ instructions
say I should be able to do---with a bit of monkeying around.

MFJ says the G5RV, when configured as a single wire fed horizontal antenna,
acts a Marconi type of top loaded vertical.

Specifically, the instructions give me two options for 160M use. One is to
feed one side of the coax at my shack with a single wire to the tuner, and
ground the other side of the coax to a good earth ground or counterpoise. I
have no idea what this becomes in this mode.

The other option is to connect the coax outer conductor to the inner one,
and feed both with a single wire from the tuner, using a good earth ground
or counterpoise to the rig.

A question is what the consensus is as to which of the above feeds would be
the better?

I could remove the balun, and then feed one side of the antenna hot, with
the other side going to ground and/or counterpoise. Again, what would this
be?

The other question is whether or not I'd be better off with two long (maybe
100') counterpoise runs in opposite directions, as opposed to a good earth
ground only?

Help appreciated.

A question is what the consensus is as to which of the above feeds
would be
the better?

Easiest way to find out is to try them. It depends on the path used,
but overall, I'd probably put my money on the "T" vertical setup being
the best. Neither just the ground, or the two radials are gonna be dx
busters, but they will work well enough to get on the air. If you run
it as
a dipole, the ground isn't much of an issue. But as a T vertical, it
is...
MK

In article ,
RB wrote:

MFJ says the G5RV, when configured as a single wire fed horizontal antenna,
acts a Marconi type of top loaded vertical.

Specifically, the instructions give me two options for 160M use. One is to
feed one side of the coax at my shack with a single wire to the tuner, and
ground the other side of the coax to a good earth ground or counterpoise. I
have no idea what this becomes in this mode.

The other option is to connect the coax outer conductor to the inner one,
and feed both with a single wire from the tuner, using a good earth ground
or counterpoise to the rig.

A question is what the consensus is as to which of the above feeds would be
the better?

The second is the more commonly-recommended approach, I believe. As I
understand it, you end up with a vertical radiator (the coax braid),
top-loaded with a big capacity hat (the G5RV proper), working against
your counterpoise wire or radials (or against just a ground stake,
which probably won't give great results due to high ground losses).

I'm rather sceptical of the first approach. If your rig is properly
RF-grounded, this approach seems little different than trying to feed
the coax directly from your tuner, except that you'll have some length
of the ground-return current coming back to your rig via its grounding
strap/wire rather than inside the coax. You're going to be trying to
drive a short horizontal antenna (low radiation resistance, in series
with a high capacitive reactance) through coax... a recipe for a very
high SWR and high losses. You may be able to get it to tune up, if
your external transmatch is a capable one, but your on-the-air
efficiency is likely to suffer badly.

If your rig isn't RF-grounded, you've got other problems with the
first arrangement :-(

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

I tried that top-hat thingy with the g5RV for 160 - but couldn't get it to
tune up.
still have not transmitted on that band.

"RB" wrote in message
. ..
I am using the MFJ G5RV, and have a coil of coax for balun purposes
between
the ladderline and coax to the shack. My G5RV works fine.

Now, I'm starting to think about using it on 160m, as the MFJ instructions
say I should be able to do---with a bit of monkeying around.

MFJ says the G5RV, when configured as a single wire fed horizontal
antenna,
acts a Marconi type of top loaded vertical.

Specifically, the instructions give me two options for 160M use. One is
to
feed one side of the coax at my shack with a single wire to the tuner, and
ground the other side of the coax to a good earth ground or counterpoise.
I
have no idea what this becomes in this mode.

The other option is to connect the coax outer conductor to the inner one,
and feed both with a single wire from the tuner, using a good earth ground
or counterpoise to the rig.

A question is what the consensus is as to which of the above feeds would
be
the better?

I could remove the balun, and then feed one side of the antenna hot, with
the other side going to ground and/or counterpoise. Again, what would
this
be?

The other question is whether or not I'd be better off with two long
(maybe
100') counterpoise runs in opposite directions, as opposed to a good earth
ground only?

Help appreciated.