On Fri, 08 Apr 2005 18:27:15 -0700, Frank Gilliland
wrote:

On Fri, 08 Apr 2005 13:59:47 -0400, Dave Hall
wrote in :

snip
Maybe you had difficulty, but there are a very large number of hams
-and- CBers who don't share your ineptitude.

A dipole is a dipole. It has 0 db of gain,


Wrong. A 1/2-wave Hertzian dipole has a gain of roughly +3 dBi in free
space.

Isotropic is a theoretical spherical reference model which does not
exist in reality. A dipole is THE reference antenna, by which most
credible gain claims are based against.


It has 0 dB when referenced to itself.

Isn't that what I just said?


and that assumes a resonant
dipole .


That's an assumtion -you- made, and it's also wrong: A resonant dipole
can be any multiple of 1/2-wave, and has a gain that differs depending
upon the length and directionality.

Then it's no longer a half wave dipole. You are now talking double
ended zepp designs, which do exhibit gain over a 1/2 wave dipole



If the dipole is non-resonant and requires a tuner to force
an impedance match, it will have further losses.


Wrong again. A tuner only adds insertion loss, which is usually quite
small if it's built with quality components. The insertion loss is
easily overcome by slightly increasing the length of the elements,
which is no big deal since the antenna is already non-resonant.

You fail to consider the standing waves which will still be present in
the feedline due to the mismatch. A tuner only presents a proper match
to the transmitter. With a high mismatch in the feedline, losses
increase as well and creating a tendency to radiate from the feedline.
In order to compensate for this the tuner should be mounted at the
feedpoint of the 4:1 balun that is normally used to feed 450 Ohm
ladder line to such designs. But such is impractical for guys who
change bands and frequency often, unless the tuner is automatic.

But keeping with the original perspective, of a simple antenna system
for Vinnie, this falls far short of that objective.




It won't stand a
chance against a commercially produced (or home made if you are
so-inclined) 5/8th wave vertical (with proper radials, not an Imax).


Well guess what, Dave -- a 5/8-wave antenna is a non-resonant antenna
and requires some method of impedance matching. Thank you.

A 5/8 wave is most certainly resonant. It's just that the feedpoint
impedance is high and needs to be transformed. It's a different issue
than forcing a match from something that is not resonant naturally.

You can have a 1:1 SWR but not be 50 Ohms.

Time to read some more books. Or better yet, befriend an experienced
ham to show you.


I've done this type of
antenna myself and never had any problems with local contacts -- in
fact, it worked a lot better than the 9' whip on the truck.

I find that very hard to believe, assuming identical height and
conditions, as my own experiences prove otherwise.


Oh, the humanity.....

This coming from someone who looks at people who share healthy
relationships as being "co-dependant", and prefers instead the
isolation of "independence".


I ran a home brewed wire dipole on CB years ago, and used it in
addition to my main 5/8th wave antenna. While the dipole worked well
when the skip was running, locally, the signal from the dipole was a
few "S" units less than the ground plane. With 4 watts of power, you
don't get much range on a horizontal wire dipole strung in a tree.


Well there's your problem, Dave -- I didn't say anything about
horizontal. On the contrary, it's better if it isn't.

Yea, if you're talking local. For DX, horizontal is usually better for
a number of reasons, most notably a lower noise floor and better take
off angle.


A horizontal dipole can have a wide variation in take-off angle
depending on height above ground, ground resistance, proximity to
other structures or objects, etc.

Yea, so?

And the noise floor may be slightly
lower but that's a product of it's directivity, as compared to a
vertical which is omnidirectional.

No, it's a product of the fact that most atmospheric and man-made
noise tends to be vertically polarized.


A pair of phased verticals, as well
as any other directional antenna or antenna array, will also have the
effect of lowering the noise floor.

Not if the noise isn't concentrated in a single direction.


Like I said
before, just throw some wire up into the trees (or whatever tall
object happens to be available). Didn't you read the link I posted?

Of course. But a dipole is a basic antenna. It has no gain.


Wrong again. As I said before, a 1/2-wave Hertzian dipole in free
space has about 3 dB gain over an isotropic antenna; but a dipole is
merely an antenna with two elements and is not limited to a 1/2-wave
Hertzian configuration. Not only that, but a tuner isn't limited to
dipole antennas -- they can load up a long-wire just as easily.

Ah, so you're changing the parameters of the discussion. Long wires
are inefficient on CB as well. Been there, done that.





A properly
made purpose built CB antenna will out perform it.


Get a clue, Dave. You're an Extra, right? What's the name of that tech
school you claim to have attended?

What's your call sign Frank?

Frank, all the king's horses and all the books you read will not make
up for your glaring lack of experience. Get out from behind the table
and DO something, and then report back.




Let's look at this from a practical standpoint. If a non-resonant,
tuner fed dipole worked so well, then why aren't all CB'ers using one?
Why would people want huge 5/8th wave antennas then? Better tell Jay
to forget about selling his Interceptor, since a simple non-resonant
dipole will work just as well and for far less money.


This resounds back to your argument that roger-beeps were illegal
because most radios didn't include them. The problem is that a tuner
requires a little skill and practice to use, which is beyond the scope
of the intended purpose of the service (a plug-n-play radio service).

Antenna tuners were available as an accessory for CB for less than the
cost of a good SWR meter. Granted they were simple coaxial in and out
tuners.

A tuner requires readjustment when changing channels within the CB,
and most CBers don't want to deal with the hassle.

So you are now claiming that CB'ers are too "dumb" to handle that?

And to add further evidence to your lack of experience with CB, it was
common that "matchboxes" were often used by CB'ers to "correct" a
mismatch within their antennas. Instead of taking the time to properly
tune the antenna, they forced the match with the tuner. The radio was
happy, as it saw a 1:1 SWR, but the signal was not so good. When a
more knowledgable person would finally retune the antenna, and the
tuner was removed, signal improved considerably.


Regardless, there
are still many CBers that do indeed use a tuner, not just with prefab
antennas but also with homebrew and beverage-can hooks.

None of which are work a tinker's dam for local CB communications.


And just about
every CBer who runs a tube linear uses a tuner because it's built into
the amp, which by itself blows big holes in your "practical" argument.

Not at all. A tube amplifier requires a tuner because the impedance of
a tube is much higher than 50 ohms, and needs to be transformed. It's
not practicality, it's necessity.


Then there is the issue of the non-resonant 5/8-wave antenna..... oh,
Dave, when will you learn?

The question is Frank, when will you start?


A non-resonant dipole has ONE big advantage. It's a compromise antenna
that will work on all the HF bands. That's great if you don't have the
room to put up single band antennas for each band. But like any
compromise, it will not work as well as a dedicated antenna for each
band. Such a compromise is usually acceptable for a ham who has 1500
watts on tap. But for a 4 watt CB'er, who needs to squeeze every watt
of ERP he can for best local range, he needs a high gain efficient
antenna.


If that were the case then every CBer would have a 5-el yagi on a 30'
mast and a 9' whip on their vehicles.

Most high performance CB'ers do.


For ham band use, I agree with you, just not for CB.


What's the name of that tech school, Dave?

What's your call sign Frank?


I'm not a ham.

Yet you are trying to impart your opinion on a subject you have not
participated in?



I answered your question, now you answer mine: what's
the name of your tech school, Dave?

The fact that you keep asking, makes me all the less likely to tell
you.


Frank, your experience with both ham and CB radio is sorely lacking.
You read a few books and web sites and think you have all the answers.
OTOH, I've walked the walk for the last 30+ years and have played with
more antennas and equipment than I can remember. I have also been in
contact with people in the know when it comes to antennas. What I
know, I know through experience, and that's worth 10X what you read in
any book.


Which explains why your theory is severely lacking. If you took the
time to actually learn why these things work and -then- applied them
to your experiences, you could be the guru you think you already are.
But you don't and you're not. Instead you do things backwards: you
theorize about radio based on your own experience, then read only
enough to validate your own conclusions whether they are right or not.

If the evidence supports the theory, then it's valid. If not, then the
theory is wrong. You are a perfect example of someone who is
book-smart and street foolish. You will sit there and tell people, who
do these things every day, exactly why they can't possibly work. While
we sit here and laugh at you, because we've been there and done that.


Check this out, Dave: Education doesn't come from a textbook that some
geek sat down and wrote just for ****s and giggles. It's a compendium
of knowledge that has been collected from over a century of research,
experimentation and practical experience by experts in all aspects of
the field. Those experts didn't become experts simply by playing with
CB radios as a hobby for 30 years. And an education doesn't include a
couple textbooks, a few lectures and a test -- it also includes years
of experience with the practical application of that knowledge.

No kidding. You seemed to have failed the "practical application"
aspect. Hell, you never even heard of the term "drying out" in
reference to electrolytic capacitor aging, and you try to cover this
glaring hole by claiming a pompous, superior attitude as if this was
beneath you.

When
you mock those that have a formal education and extensive experience
in electronic communication then you mock the same people who made the
television set you watch way too much, the telephone and cell-phone
infrastructure that keeps this world talking, the NASA and JPL
engineers who communicate with space probes billions of miles away,
etc, etc, etc.

I'm not mocking them. They know what they are doing. And I work with
many of them on a daily basis. You probably have products in your home
(or will) that I have had a part to play in their development. I
work in the field every day. I am not mocking them, I am mocking you.
You who CLAIM to be educated, but evidence suggests you are sorely
lacking in practical application of whatever it is you might have
learned.

While I may not have participated in any world-changing
technology, I certainly have an education and the experience in the
field that puts you to shame.

While you tend bar and drive a 20+ year old truck......

Yet -you- try to teach -me- theory based
on your education from a third-rate vocational tech school, a few
years in a CB shop, and your experience in =amateur= radio.

As far as you know. But it is evidently light years ahead of those
internet websites you lift your information from while you sit at home
alone with no other people to "relate" to.


And here's the kicker: Do you have any idea where I came up with the
idea to just throw a couple wires in the air and load them up with a
tuner? A ham.

Not all hams are mensa candidates. And most hams know that one antenna
solution, which may be great in one application, is not necessarily
good in another. In ham radio, there is no "one size fits all" answer.
But then again, you wouldn't know that. You're not a ham (or CB'er).

Dave
"Sandbagger"
http://home.ptd.net/~n3cvj