Mark Keith wrote:

Cecil Moore wrote:
It's a pretty good antenna for 80m, 40m, & 20m. My web page shows
how the "matching section" gives a pretty good match to coax on
80m and 40m. Mine also worked well on 12m.

I guess if a 2 S+ unit deficit compared to a coax fed dipole is
"pretty good", maybe so..."The average 2 s unit loss I saw was on 40,
not 80. 80 would have been worse. I remember a field day about 4-5
years ago where they used a G5RV on 80m. This particular one,
commercially made, was pitiful. My mobile antenna would have trounced
it...Was totally useless for us.

Of course, the quality of a G5RV makes a difference. Knowing all you do
about dipoles, I'll bet you could design a G5RV that is virtually
identical in performance to a dipole on 75m and 40m. The losses due
to SWR are pretty negligible using RG8x.

One note, however. The G5RV's null off the end of the antenna is about
6dB deeper than a 1/2WL dipole on 40m. Perhaps that explains part of
your findings.
--
73, Cecil http://www.qsl.net/w5dxp



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Thierry,

First, there is some confusion as to what a G5RV is. Some people refer to
any dipole fed with open wire line as a G5RV. As far as I can determine, a
G5RV is 3/2 wavelength long on 20 meters, fed with 1/2 wavelength at 20
meters of 450 ohm line.

I ran EZNEC on such an antenna, and got SWRs below 3:1 on 20 and 80 meters.
If you juggle things, you can get it below 2:1 on 20. Free space gain was
about 1 dbi on 20, and 2 dbi on 80. On 160m, the free space gain was about
2dbi, but that is almost meaningless because the impedance was 1 - j600.
So, even if your antenna tuner lets you get an SWR of 1:1 on 160, you are
really loading the transmitter into the losses of the transmission line, and
not the antenna. Note that just the DC resistance of 100 feet of #14 wire
approaches 1 Ohm.

Tam/WB2TT

"Thierry" Thierry, see http://www.astrosurf.com/lombry/ wrote in message
...

Hi,

Thanks for all answers.
Ok for the capacitance and other loads than destroy the ability of the 31m
G5RV to work on 160m.
But I must say that on 160m, my TS-570D automatic tuner does a good job. I
do not remember the value but I think that I get a SWR 1:1
I can reach the end the S-meter scale in emission, but at first sight
nobody
hear me, although on 80m I arrived 59++ in near countries.
(if I had observed a high SWR value on my S-meter- say over SWR 3:1 or so,
in all cases I know by experience that I could not emit the slightest
signal
or it should have been very weak).
But I wonder that having a SWR 1:1, nothing looks wrong (not heat, etc at
first sight), but the result is 0.0 on that band !!

PS. As for the one like G4FGQ saying that a multiband G5RV is not a good
antenna or the others saying that it can only work on 20m, I have to deny
these opinions.
I confirmed over 250 DXCC in one year at less than 100 W PEP from 80 to
10m,
including WARC. It works ! Not as a beam of course. But very well for what
it cost (about 100 euros). That stays an excellent investissment, not
necessary if you are hunting DX or want to participate in all contests
(that
stays a dipole than I work barefoot) but for ragchewing in local QSO
(inside
a radius of to say 5000 km) it is perfect. Now if you are a DX hunter or
want to reach all pileups with ease, you can add it an amplifier (as I
listen most far DX at least 53 or so) or purchase a performing "DX"
antenna,
I mean a 5-7 ele beam to place 10m high in an open field.

73
Thierry
ON4SKY, LX3SKY
http://www.astrosurf.com/lombry

What becomes all the energy sent by my TX on 160m ? What become de
standing
waves and reactive load ? Is it possible than all 100W are lost in the
coax
or the feeder without be emitted ?

Who could explain me this ?

Thanks

Thierry
ON4SKY
===========================

G5RV - WHERE THE POWER GOES ON 160m

Efficiency = Power into / Power out of

Efficiency % Location
========= =======
70.4 L-tuner
21.9 Coax line
78.8 Open wire line
11-6 Antenna wire and soil under anrenna

Overall radiating efficiency at 1.9 MHz = 1.40 %

or 18.5dB, or 3 S-units down relative to a very high 1/2-wave dipole.

Download program DIPOLE3 from website below. It analyses performance of any
dipole, of any length, any wire diameter at any height, and any lengths of
any types and combinations of feedlines. Also calculated are L and C
component values of L-network to match to 50 ohms.
----
=======================
Regards from Reg, G4FGQ
For Free Radio Design Software
go to http://www.g4fgq.com
=======================

Many thanks Reg, good link.

Thierry

"Reg Edwards" wrote in message
...
What becomes all the energy sent by my TX on 160m ? What become de
standing
waves and reactive load ? Is it possible than all 100W are lost in the
coax
or the feeder without be emitted ?

Who could explain me this ?

Thanks

Thierry
ON4SKY
===========================

G5RV - WHERE THE POWER GOES ON 160m

Efficiency = Power into / Power out of

Efficiency % Location
========= =======
70.4 L-tuner
21.9 Coax line
78.8 Open wire line
11-6 Antenna wire and soil under anrenna

Overall radiating efficiency at 1.9 MHz = 1.40 %

or 18.5dB, or 3 S-units down relative to a very high 1/2-wave dipole.

Download program DIPOLE3 from website below. It analyses performance of
any
dipole, of any length, any wire diameter at any height, and any lengths of
any types and combinations of feedlines. Also calculated are L and C
component values of L-network to match to 50 ohms.
----
=======================
Regards from Reg, G4FGQ
For Free Radio Design Software
go to http://www.g4fgq.com
=======================

"Thierry" Thierry, see http://www.astrosurf.com/lombry/ wrote in message
...

"Jerry" wrote in message
.. .

"Reg Edwards" wrote in message
...
The moral is - DON'T USE A G5RV.


Yup! I bought one in the late 80s and found that it was the craziest
acting
thing I had ever used! It most often
drove my Yaesu tuner bonkers; other times it would
settle down to an "acceptable" SWR. I fiddled with it
for a summer, and finally threw it out.

Hi,

Sorry to say that but you experimented a bad experience.

Who else has had non-success with this antenna?



or have not enough
knowledge to use it properly.

Wanna BET? I've been doing this stuff since I was a child of 8--trying to
get everything from a window screen to
work to all sorts of wires and verticals. I learned from
quite a few mistakes. Like wondering why I couldn't tune
in those "Donald Duck" sounds (was SSB, but I was too
young and new to know that). Or pretending that those
heterodynes were airplane engines and I was a bomber
pilot (drove my Mom crazy! and also led me to learn to
fly!

Just because something doesn't work for *me* does not
make me an idiot. If it works for you, FINE! If it doesn't
happen to work for me, that's fine, too. I didn't like the antenna, it made
my Yaesu tuner go nuts, did things that
couldn't be explained by usual antenna theory, and I shucked it.

Jerry
K4KWH


I know several OM in ON that use G5RV, W3DZZ and alike, and even longwire
of
about 20-30m that have similar results than mine.
And if the G5RV is always sold (thare a dozen variantes, see my website)
after decades, there is a good reason : this is because it works well !

Never hear on bands OM working with dipole and G5RV ? There are a lot !
better, G5RV offer you the best quality/price ratio !

73's

Thierry
ON4SKY

I then made me a
75 M doublet fed with ladder line. .......it's still up there.

Jerry
K4KWH

Specially one with any coax in the feedline.

If you've bought one, you've been robbed.

Use a random length dipole, longer than about 1/3 of the wavelength at
the
lowest frequency of interest. Choose a length which makes best use of
the
size of your backyard. Take the 450 or 600-ohm balanced line all the
way
back to the shack. You will need a tuner and a choke balun at the
tuner.
For multi-band operation you will need a tuner whatever you do.

If you find it inconvenient to feed the dipole in the middle, and you
have
a
relatively low local noise level, then feed it at one end and make an
Inverted-L of it. It will then very likely work very well also on 160
metres.

And you will never think of using a G5RV again !

By the way - Louis Varney, G5RV, a real genuine English gentleman,
now
no
longer with us, designed his antenna to work most efficiently ONLY on
14.15
MHz, perhaps the best day-or-night, all-year-round, any part of the
sun-spot
cycle, DX frequency. It's very good. And you may not need tuner even
with
the coax. Works great with the old fashioned TS-520 with its built-in
tuner
!
----
Reg, G4FGQ

Cecil Moore wrote in message
I'll bet you could design a G5RV that is virtually
identical in performance to a dipole on 75m and 40m. The losses due
to SWR are pretty negligible using RG8x.

The only way to do that and keep a dipole pattern on both bands is to
run parallel dipoles on one coax. And thats what I run. If I only have
room for one wire, I'll make a dipole for the lowest band, and
"jumper" the higher bands, using insulators and clips to bypass them.
Still dipole performance for each band...

One note, however. The G5RV's null off the end of the antenna is about
6dB deeper than a 1/2WL dipole on 40m. Perhaps that explains part of
your findings.

Nope, don't think so. Wouldn't that be on 20m? We used it on 80m. The
pattern should have been about the same as the dipole, considering
it's shorter than the dipole by 20-30 ft. The problem with the one we
ran was feedline and tuner losses. It made my 100w feel like 10w at
the rate we were cutting through the summer noise. Worst antenna I've
ever used on that band. What I never could understand is why we
were using a "compromise" antenna out on field day, when we have
enough room for anything. That seemed to be the normal pattern every
year, until I put my foot down..."for me to use personally" I never
could fathom that, when a dipole is only 20-30 ft longer, and the
overall efficiency is usually a large magnitude greater. Like I said,
after that field day, and all my lost hair from pulling it out, I said
never, ever, again.
If anyone wants to run one of those compromise antennas, G5RV,
windoms, etc, etc, be my guest. But don't expect me to use it. I'll
run like anthrax spores are on the radio. I can't afford to lose
any more hair. MK

"Thierry" Thierry, see http://www.astrosurf.com/lombry/ wrote in message ...
"Reg Edwards" wrote in message
...
The moral is - DON'T USE A G5RV.

Specially one with any coax in the feedline.

If you've bought one, you've been robbed.

Hi,
At first sight you never uses a G5RV. You opinion is completely false and
will induce novices (and other if I beleive you) in error.

Have you ever actually compared a G5RV to a coax fed dipole on 80m?
I'm talking A/B tests quickly using an antenna switch. His opinion is
most certainly not false. My first hand tests confirm his opinion.
Yes, I didn't make the G5RV's and Windoms that were tested against,
but I wouldn't bother using something like those anyway. It's not my
fault the the ones I tested against were poorly engineered. They were
all storebought antennas. Most made by a co. that uses a state for
part of it's name.

So read this and learn from the master, G5RV himself :
http://www.astrosurf.com/lombry/qsl-g5rv.htm

Even he usually recommended you do away with the junk, and run all
ladder line if using for all bands. The antenna as he designed was for
20m only.

I confirmed over 250 DXCC in one year with the G5RV at less than 100 W PEP
from 80 to 10m, including WARC. It works !

That doesn't mean anything though. You could do that with a mobile
antenna and 10w. How many qso's an antenna makes is not a good
judgement of performance.

Not as a beam of course. But very
well for what it cost (about 100 euros). That stays an excellent
investissment,

I think making a dipole from your own wire, is more cost effective.
Not to mention the best performer, being most won't ruin it by adding
a micky mouse feedline setup.

not necessary if you are hunting DX (away that to say 8000 km
in low solar acticvities like now) or want to participate in all contests
(that stays a dipole than I work barefoot) but for ragchewing in local QSO
(inside a radius of to say 5000 km) it is perfect.

No, it's far from perfect. On 75m phone, where most are closer than
500 miles, my coax fed dipole will eat that G5RV for lunch, if it's
the type and fed like the ones I usually see.

With an average emitting
power of 50W or so, most hams receive me in voice 59 or more, even 57 up to
VE, east K, VP5, FY, YB. More far the signal decreases (53 and less). But
this is a beam after all.

Again, signal reports are not an accurate indicator of antenna
performance, unless you quickly A/B with a switch with a comparison
benchmark antenna like the dipole. If you are two S units under me,
you would still make most all the same contacts I would. You would
just be 2 s units weaker. On an average radio, 2 S units is probably
about 10 db or so. I say this, because most all that change from 100w
to 1kw, usually increase by about 2 S units on most radios I see. When
I compared my dipole to one windom at a field day, and saw 2 S units
better performance on the dipole, just in the loss of efficiency with
the windom, that means he would have to run a KW to equal my 100w.
Thats no way to live. Just because they can still make most of the
qso's I do, doesn't mean the antenna is just as good. If I'm 20 over 9
somewhere, you would still be 10 over 9 if you used your antenna at my
qth. MK

"Jerry" wrote in message
.. .

"Thierry" Thierry, see http://www.astrosurf.com/lombry/ wrote in message
...

...
I didn't like the antenna, it made
my Yaesu tuner go nuts, did things that
couldn't be explained by usual antenna theory, and I shucked it.

Hi,

Have you ever try to solve your problem ? Replacing a component (feeder ?)
or doing measurements, etc.
That helps !

Thierry


Jerry
K4KWH