On Tue, 28 Dec 2004 02:36:11 -0500, Gary wrote:

I've looked at some commercial "full size" G5RV's and the leg lengths
are about 51 feet long each, that seems a tad short for 80 meters.

That's because the "missing" portions are in the open wire section.
It still works at 80m and can be fed with 75ohm coax at the lower end
of the line via a 1:1 balun. Better still would be to bring the open
wire section into the shack and to an ATU.

From what I remember from using one of these many, many years ago, I
used 29ft 6 inches of 300 ribbon feeder as against 32 - 33 ft of open
wire (300 ohm ribbon has different velocity factor to the open wire
and 450 ohm ladderline)

Would I experience quite a bit of loss in the tuner ( External ) Or
maybe I should try and erect a dipole with leg lengths as long as I
can and feed it with 450 Ohm Ladder line or 300 Ohm twinlead and be
able to operate on 30 meters ?

Yes ... and use the 450 ohm ladder line

I understand the G5RV doesn't work too
well for 30 meters,

It was never designed for that band as we didn' have that allocation
when Louis, G5RV, introduced the antenna. That's why it's best to use
open wire right down to the shack. You can then use it on all of
todays HF bands via an ATU. The 102 foot "top" is also no magic then.
Make the legs as long as you can .... you might even be able to work
160 metres if you can get out enough wire!

BTW, please dont buy a G5RV !!! They are so easy to make and work out
cheaper. You also have the satisfaction that you made it yourself,
which is what amateur radio is (hopefully largely) about.

Have you considered putting up a 50 ohm coax fed inverted V 80 metre
dipole and then adding a 40 metre dipole to the same coax feed point?
It can come down at a sharper angle than the 80m one or run at right
angles to it. You'll then have 80, 40 and 15 metres since the 40m
dipole will work has 3 half waves in phase on 15. You can hang dipoles
for the other bands to the same feeder as well. Be prepared for some
cut 'n try of course! This system elimates the need for an ATU but
you'll find the usable bandwidth on 80m to be only just a couple of
dozen kHz or so. The open wire version will be tuneable across the
whole of each band via the ATU.

Good luck,

Peter, G3PHO