On Fri, 26 Sep 2008 15:16:47 GMT, "JB" wrote:

I had a hard time separating what he actually thought from what he was
complaining about.

I have yet to read what problem he's trying to solve. There has to be
a reason for all that effort.

I find that even if go to great pains to be extremely clear and eliminate
all distractions from a document, and write for a 6th grade reading level,
only 10% will actually get it. Some will cling to a word that has special
meaning to them and go on a wild tangent and some will only get 3 or 4 words
out of it, throw away the context and quote those words.

I think a 10 year old level is more appropriate. It's roughly what TV
shows try to target.

Topic drift is a problem, but boilplate solutons are what drive the
technical newgroups and mailing lists. Whenever someone asks a
question, the vocal experts are usually first to misinterpret the
question and provide their favorite boilerplate answer. In my case,
it doesn't matter what antenna problem you're having, a computer model
will provide the answer. Lots of other approaches (careful
measurement, ignore VSWR and use a field strength meter, etc) that
vary with the person providing the analysis and boilerplate. OF
course, the answer never completely solves the original problem, so
the discussion drifts off into optimizing the computer model, instead
of fixing the antenna problem. My guess is about 3 back and forth
postings and the original topic is lost. Kinda like this posting.

Anyway, I've never used or built a G5RV, know nothing about the
antenna type, and propose building a computer model of the antenna,
supporting structure, and nearby buildings, that will solve any
problem with a G5RV, including operating it on bands for which it was
never designed.



--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Thu, 25 Sep 2008 18:33:11 -0500, "Howard Kowall"
wrote:

yes i have built a dipole and it works good with the manual tuner
BUT now my new rig has a built in tuner and of course it wont tune it
the dipole i built was cut for 3.747mhz and works great without a tuner
but with the auto tuner it wont tune anyware but 80mtrs
is there a magic number for a dipole to make it tunable on 80 and 40



A popular antennas over here in the UK is a centre fed doublet,
80 to 100 Foot top with 450 ladder line feeder into your ATU. You
will need a balun near the shack end if your ATU is coax only input.
This makes feeder access into the shack easier than balanced feeder
coming in. DX Engineering makes excellent baluns for this purpose.
This antenna will work all HF bands, 80m and up.

At the moment I have an 80m inverted V dipole and a 40 metre one fed
with the same RG213 coax (about 60 feet of the stuff). These antennas
work worldwide DX very nicely, even though the apex is only up at 32
feet. NO atu needed :-)./ However I'm shortly going to erect the
doublet described abovce so that I can work all the WARC bands as
well. I already have a 3 el beam for 10/15/20m.

73

Peter G3PHO

(Peter) wrote in news:48de67d3.1883747435
@news.virginmedia.com:

A popular antennas over here in the UK is a centre fed doublet,
80 to 100 Foot top with 450 ladder line feeder into your ATU. You
will need a balun near the shack end if your ATU is coax only input.
This makes feeder access into the shack easier than balanced feeder
coming in. DX Engineering makes excellent baluns for this purpose.
This antenna will work all HF bands, 80m and up.

Modelling suggests that the efficiency of such an antenna degrades quickly
for dipole lengths less than about 35% of a wavelength.

80' is 28% of a wavelength at 3.5MHz.

Owen

Owen Duffy wrote:
Modelling suggests that the efficiency of such an antenna degrades quickly
for dipole lengths less than about 35% of a wavelength.

Walter Maxwell agrees. In "Reflections", he suggests the
minimum length for a dipole should be 3/8WL.
--
73, Cecil http://www.w5dxp.com
"According to the general theory of relativity,
space without ether is unthinkable." Albert Einstein

On Sep 25, 5:55*pm, Danny Richardson wrote:
On Thu, 25 Sep 2008 18:33:11 -0500, "Howard Kowall"
wrote:

yes i have built a dipole and it works good with the manual tuner
BUT now my new rig has a built in tuner and of course it wont tune it
the dipole i built was *cut for 3.747mhz and works great without a tuner
but with the auto tuner it wont tune anyware but 80mtrs
is there a magic number for a dipole to make it tunable on 80 and 40
thanx
howard

Howard,

Before you go sailing off into space on the GRV check this out.

http://www.degendesigns.com/Downloads/TheEasyWay.PDF

Danny, k6mhe


Danny,

Thanks for sharing this link. I found the article very well written
and some very good information on SWR and suggestions on antenna
design. Looks like the author is SK, so probably no way to follow up
with questions, as suggested in the article. I'm curious as to when
the article was written. I am just getting back on the air after
several years of inactivity. I am trying to decide what type of
antenna to put up in a 1/3 acre city lot without any tall trees. I'm
thinking about an off-center fed dipole. Looks like an 80 meter
dipole fed with ladder line and using a good antenna tuner would work
on all bands. I don't have room for a full half-wave 80 meter dipole,
but could do a bent off-center fed dipole. The Carolina Windom is
probably what I'm thinking about, but hate to pay their price for
something that could probably be home built. Also considering an all-
band vertical, mounted on the roof of my home.

Thanks again
Vee W7IBB – Utah

Vee wrote:

Danny,

Thanks for sharing this link. I found the article very well written
and some very good information on SWR and suggestions on antenna
design. Looks like the author is SK, so probably no way to follow up
with questions, as suggested in the article. I'm curious as to when
the article was written. I am just getting back on the air after
several years of inactivity. I am trying to decide what type of
antenna to put up in a 1/3 acre city lot without any tall trees. I'm
thinking about an off-center fed dipole. Looks like an 80 meter
dipole fed with ladder line and using a good antenna tuner would work
on all bands. I don't have room for a full half-wave 80 meter dipole,
but could do a bent off-center fed dipole. The Carolina Windom is
probably what I'm thinking about, but hate to pay their price for
something that could probably be home built. Also considering an all-
band vertical, mounted on the roof of my home.

Thanks again
Vee W7IBB – Utah


This paper takes the view that the final stage(s) in a PA is/are very
much like a power generating plant. And, in a very simple comparison,
it/they is/a

http://www.degendesigns.com/Downloads/TheEasyWay.PDF

However, that power generating station has carbon piles to sink the
power into and maintain a correct draw for the power the plant is
producing--until generators can be slowed or dropped off line to match
"the impedance" of the load being presented to it. The power plant has
switches and breakers to cut part of its' load to maintain a "correct
match" (or, correct impedance) being presented to its' load, etc.

In our PA's, we do not have such niceties ... the antenna must present
and hold a proper "draw" upon this power being generated in our
tubes/transistors/tank-circuits. If not, either too much current is
drawn, voltage dips, the design parameters of devices and components are
exceed and "something gives." If the load draws too little power,
voltage(s) spike, current drops, and the voltage rating of the
devices/components are exceeded and "something gives."

While the paper, in a round-about-way, does present this in an
convoluted view, it expounds on this/these events to build a case for
obsfucating SWR, forward power, etc.

But then, in old arrl literature, such inconsistencies abound ...
indeed, they can still be found in current material from this source
(arrl) ...

Regards,
JS

John Smith wrote:

...
Regards,
JS

Yanno, every time I read that 10 PAGE PAPER! it just peeves me off ...

Take his statement, "If a mismatched antenna causes power to be
reflected back down the line, they reasoned, this power obviously wasn't
radiated by the antenna."

He is using this to "poke fun at dummies who don't know what they are
taking about", this gives you the hope that "this dummy" is going to
simplify, explain and dispel your ignorance on this subject--however,
during the next several pages he does NOTHING in this direction.

That statement can be stated more accurately as, "The LOAD is reflected
back down the line!" DUH!

However, it can be pictured as power being "reflected", because it sure
as heck doesn't get to the antenna where it is anywheres near useful!
It sure as heck is going to cause stress and heating in devices and
components. A simple FSM will prove this to you in short order! And,
just touch those finals to prove the stress and heat.

The guy could state it, stupendously more, accurately in two pages,
max--the paper is only a disclosure of the fact he doesn't understand
what he is proposing to "teach" others ...

If you can't make a SIMPLE statement (or paper), on a concept, which an
average layman can understand, you probably don't understand the
concept(s) yourself ... end of story.

The paper stands in tribute to that mans ego ... sad, but true ... :-(

Regards,
JS

John Smith wrote:

...
Regards,
JS

This BS is ALL the way through this paper of his ... reading and
re-reading this paper is going to give me little sleep this night.

Take this on baluns:

"Next, he puts a 1:1 ferrite- core transformer-type balun up at the
feedpoint of the antenna. What happens? His swr comes down to 1.5:1 at
the band edges. Boy, that balun really solved the problem.
Right?.....WRONG! In this case, if his rig would load up (or if he used
a transmatch) he would be much better off without a balun."

YES, that balun did solve his problem! Now the feedline is not the
major element in his antenna, and giving God knows what radiation pattern!

AND, in NO case would "he" be better off without a balun (well, unless
"he" had designed the feedline to be part of "his" antenna. Or, the
antenna was "perfect" and would always remain in that state,
theoretically ... )

I mean this ALL just galls me ... and then new guys coming along read
this crap, take it as "the holy word" since it has "arrl" attached to
it, and it ALL begins again ... ALL over.

Regards,
JS

John Smith wrote:
If you can't make a SIMPLE statement (or paper), on a concept, which an
average layman can understand, you probably don't understand the
concept(s) yourself ... end of story.

Here's a simple statement he could have made about reflected
power not being lost:

In a conjugately matched system using lossless transmission line:

Source Power = Forward Power - Reflected Power = Load Power
--
73, Cecil http://www.w5dxp.com
"According to the general theory of relativity,
space without ether is unthinkable." Albert Einstein

Cecil Moore wrote:
John Smith wrote:
If you can't make a SIMPLE statement (or paper), on a concept, which
an average layman can understand, you probably don't understand the
concept(s) yourself ... end of story.

Here's a simple statement he could have made about reflected
power not being lost:

In a conjugately matched system using lossless transmission line:

Source Power = Forward Power - Reflected Power = Load Power

Cecil:

Conjugately? Gawd man, that terms reminds me of yesteryears (Cecil,
that term was an antique when I came along--your age is showing ;-) ...
) lol However, the wife and I do get along, conjugately, from time to
time--but, THAT IS a story for another day ... EVIL GRIN

I believe so, that "reflected power", is certainly causing some of the
heating of the semiconductors (finals.) And, some of the "loss" due to
SWR is not "lost" (as heat) at all--you can count the power radiating
from the transmission line as "power delivered", I suppose ... but I
will agree with "him" on one point, it darn sure well ain't endin' up in
"SWR heaven!" ROFLOL

At extreme power and extreme SWR I have seen the dielectric of coax
puncture and burn ... seemingly, gloriously, dramatically,
instantaneously. And, yet, another reason why a balun may be a good
idea ... if you grab hold of your coax and it feels warm, suspect
dielectric heating and major loss(es) ...

Another thing, with the "correct" transmatch, a couple of coat-hangers
can be made to look as right as rain ... at 160m! That don't mean it is
right ... that paper burns me bum.

Regards,
JS