Reg Edwards wrote:
R.L.Varney himself never gave a value to Zo. He didn't need to. He was
concerned mainly with 14.15 MHz. It would be unfair to accuse him of
not understanding the serious effects of Zo on other bands.

However, in The ARRL Antenna Compendium #1, he did describe the
matching section well enough to calculate his Z0. It is #14
copper open-wire separated by 1.75 inches. I'll bet that's
an improvement over 300 ohm twinlead.
--
73, Cecil http://www.qsl.net/w5dxp

Reg Edwards wrote:
R.L.Varney himself never gave a value to Zo. He didn't need to. He
was
concerned mainly with 14.15 MHz. It would be unfair to accuse him
of
not understanding the serious effects of Zo on other bands.

However, in The ARRL Antenna Compendium #1, he did describe the
matching section well enough to calculate his Z0. It is #14
copper open-wire separated by 1.75 inches. I'll bet that's
an improvement over 300 ohm twinlead.
--
73, Cecil
==========================================

Cec, the facts are, G5RV never mentioned Zo, either because he never
attached any importance to it, or he didn't understand its relevance
to other bands.

When considering other than 14.15 MHz perhaps he should have done. In
any event, everybody else has followed suit.

Now we have the situation where dozens of people are busily seriously
comparing all-band versions, one with another, and unknown to each
other they are all using different value Zo transmission lines.

Many of those who purchased the antennas, or just copied G5RV's
construction, havn't the foggiest idea what their particular Zo is.
Yet, from an analysis point of view, which you are involved with, it
is a crucial matter.

Your own Zo is a non-standard 375 ohms because you measured it. Yet
you describe its performance to others as if everybody else's Zo is
the same, whereas there is no hope of anybody else reproducing your
particular results.

Its all a load of nonsense!

If anybody, at this very late stage in the art, should still wish to
acquaint themselves with the less than mediocre performance of a G5RV,
then download program DIPOLE3 from website below.

DIPOLE3 is a general purpose program which deals with a dipole of any
length, at any frequency, plus balanced-twin feedline of any length
and any Zo, plus balun, plus coax line of any length and Zo, plus
L-tuner. So it happens to include a G5RV.

All the data for the original G5RV can be inserted in the program by
depressing one key. Modifications to the system, such as changes in
Zo, can easily be done and changes in performance immediately seen.

The final important output figure is overall loss between transmitter
and radiated power. Individual losses in the antenna, in the two
transmission lines, and in the tuner, are reported seperately. Even
the tuner L and C settings and their circuit locations are predicted.

It is very easy to sweep over the HF frequency range to check when low
swr happens to fall into amateur bands. (Unfortunately it doesn't do
this very often.)

It is also easy to change the length of transmission line (as Cecil
recommends and advertises) to try to obtain an swr of less than 2:1.
But you can use any dipole length other than 102-feet to play with
this useful aspect.

Accuracy is better than needed for the intended purposes and is
generally as good as the accuracy of program input data. There is only
one known trivial bug which occurs when dipole length is extremely
short compared with wavelength. But clearly this is not of
consequence.

What more could you want from a G5RV? There's nothing to do but erect
it and then compare it with a dipole of any other length with an open
wire feedline of thick wire, of no particular length, all the way to
the shack. Plus a choke balun.

I'm still on Red, South African, Western Cape.

Download DIPOLE3. Its free to USA citizens.
----
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........

Reg Edwards wrote:
Cec, the facts are, G5RV never mentioned Zo, ...

Now Reg, you know that most statements using the word
"never" are false. Here's a quote from G5RV, himself,
from "The G5RV Multiband Antenna ... Up-to-Date" in
The ARRL Antenna Compendium, Vol. 1.

"If you decide to use 300-ohm ribbon type feeder for
this (series) section, it is strongly recommended that
the type with 'windows' be used. ... Since the VF of
standard 300-ohm ribbon feeder is 0.82, the mechanical
length should be 28 ft. However, if 300-ohm ribbon with
windows is used, its VF will be almost that of open-wire
feeder, say 0.90, so its mechanical length should be
30.6 ft."
--
73, Cecil http://www.qsl.net/w5dxp

Now Cec, your reference to my use of the English language, which you
well understand, is an admission that you have lost the argument -
whatever that may be.

And you, more than most people, should realise that it's fatal to use
ARRL publications as Bibles.

The facts are, the Zo of the G5RV trannsmission line is indeterminate.
Everybody has a different but unknown value.

And it follows that, so are all the interminable discussions on the
subject which take place on this and other newsgroups. Hardly
educational. They approach amusing nonsense!

But no doubt you will wish to further dig yourself in and have the
last word. Go ahead! ;o) smiley
----
Reg.

Owen Duffy wrote:
http://www.vk1od.net/temp/G5RV-W5DXP.GIF

Owen, what software did you use to generate that graphic?
--
TNX & 73, Cecil, http://www.qsl.net/w5dxp

In article ,
says...
The G5RV antenna can be found by googling. Anyone using this
arrangement. It uses a coax feed to balanced feed (which variously acts
as radiating elements, depending on the band). The author says a balun
is not needed but then describes an RF choke that sounds a lot like a
balun. I am also concerned about TVI with this system.

I've been using a "shorty" version of the G5RV (not the full length
version, due to space limitations -- mine is capable of operating on 40-
10 meters) with moderate success, even at QRP power levels. Rig is an
FT-817 with no amplifier, so max power is five watts, often quite a bit
lower.

--

-- //Steve//

Steve Silverwood, KB6OJS
Fountain Valley, CA
Email:

There's more nonsense, old wives tales and gobbledegook generated by
THAT antenna than all other antennas put together.

Just erect the longest and highest dipole you have space for and feed
it with 450-ohm open-wire line all the way to the shack. If you don't
have a balanced tuner, use an unbalanced tuner with a choke balun. An
unbalanced tuner will probably be better anyway.

To lengthen a dipole make an inverted-U. Or make a Z with it.
----
Reg.