"Lancer" wrote in message
...
On Wed, 29 Oct 2003 02:52:33 GMT, "BuckEye" wrote:


"Lancer" wrote in message
.. .
On Tue, 28 Oct 2003 23:10:42 GMT, "BuckEye" wrote:

I agree to all of the above except a 1/4 wave is a 1/4 no matter what.
A
so
called loaded 1/4 is a loaded antenna not called a 1/4 anymore. Once a
antenna has been shortened by any means, shorter than the physical 1/4
wave
antenna ( 1/4 wave including the velocity factor ), top hats, loading
coil,
or ant other ways it is not clamed to be called a 1/4 wave anymore.
I did say 1/4 whip on the post, as most everybody should have known
it
to
be the 108" antenna.


I don't know where Doc is heading for with his statement, but a
shortened antenna ( like the Xterminator) is 1/4 wave "electrically"

Velocity factor isn't a factor when you determine antenna length,
except certain antennas that are made from transmission line.

Maby you can explain how a antenna is 1/4 so called " electrically 1/4 "
if
it is not a 1/4 wave like a 108" whip.
If it has a coil in it it, and shorter than the 1/4 it is a loaded
antenna
NOT a electrically 1/4 wave equivelement .
If that was the case then a very loaded antenna that was 12" tall NOT 8'
could also be called a 1/4 wave "electrically"
What makes then a antenna 1/4 wave "electrically", because it matches
the
50 coax?

A coil in a short antenna cancels out the capacitive reactance making
the antenna resistive at the operating frequency OK TRUE . The
coil makes it
"electrically" a 1/4 wavelength
Why does the coil make it that way.
Nowhere in any theory does it state that. Its just another ways to match the
coax to free air. That's all the antenna does.

Why do you keep trying to say its "electrically" a 1/4 wavelength. Just
because it
can be loaded with a matching device ? Shows a good match.
This could be taken to the extreme and if the antenna was reduced to only
one inch
in length, tuned and matched would it be electrically" a 1/4 wavelength .
No its just a resonate circuit with no relation to a
wavelength. In fact a conductor does not have to be any wavelength to
radiate at all.
When matched any length of wire will emit all the power applied to it.

More than likely it won't be 50
(We all know thats true)
ohms, usually quite less, unless some kind of matching is used at the
base.



Velocity factor IS importment when cutting a element to the proper
length.
Typically a antenna element can range from .91 to .99 of the true open
space
length.


The number (.91 to .99) are correct for the difference between an
antenna in free space and erected near earth. Its not from the
velocity factor of the antenna.
Its because the antenna is close to the earth and other
conductive objects (tree, buildings and power lines) which present
stray capacitance that tunes the antenna lower in frequency than a
free space antenna. Its called "end effect" and is more prevelant
the closer an antenna is other objects.

If so how do you explain in some long wire antennas its even 1.05 times
longer than the freespace.

BuckEye wrote:

Why does the coil make it that way.
Nowhere in any theory does it state that. Its just another ways to match the
coax to free air. That's all the antenna does.

Why do you keep trying to say its "electrically" a 1/4 wavelength. Just
because it
can be loaded with a matching device ? Shows a good match.
This could be taken to the extreme and if the antenna was reduced to only
one inch
in length, tuned and matched would it be electrically" a 1/4 wavelength .
No its just a resonate circuit with no relation to a
wavelength. In fact a conductor does not have to be any wavelength to
radiate at all.

Any antenna, even a straight piece of wire has inductance at radio
freqencies. A 1/4 wave straight piece of wire will exhibit a certain
inductance at a certain frequency, shorten it to something less than a
1/4 wave and the inductance decreases. Add a coil to make up the missing
inductance and the antenna "looks" like a 1/4 wave again to the RF
source. Some of the power is dissipated as heat in the coil because of
the I/R losses of the coil.

What makes a antenna so called " looks like a 1/4 wave again to the RF".

Where does it say a matching antenna must look like a 1/4 anyway.



"Add a coil to make up the missing
inductance and the antenna "looks" like a 1/4 wave again to the RF, not so,
the impedance is now very low at its feed point. Big mismatch (you forgot
the extra device now needed to match the antenna,usally a cap or coil on the
input side.so adding just a loading coil did not make it look like a
match.Notice I said a match . NOT a 1/4 wave. RF doesn't care what the
wavelength is. Where does it say a antenna must "look like a 1/4 anyway."
The same thing could be said about a base matched 5/8 wave antenna, it shows
a good match also and its is a long way from the 1/4 wave length. and is
never said it looks like a 1/4 to the RF.
Don't confuse a match to it looking like a 1/4.

There is many things that can be changed at the antenna mounting spot, 1/2
wave 5/8 wave

BuckEye,
But all antennas are 'matched', be they exactly a 1/4 wave
length long, or 75 feet long, or 1 inch long. I'm assuming
that you mean impedance matching, right? Impedance matching
has nothing to do with an antenna being resonant.
'Doc

What the hell do you think I am saying.
This all started when some dumass said a antenna was electrically 1/4 wave
long, not 1/4 wave antenna. You either have a 1/4 wave antenna or you
don't. If its shorter, then its not a 1/4 wave antenna. In most cases it
loaded, and no more electrically a 1/4 wave long antenna.
How hard is this to understand. I think this comes from some adds that's
states it a helical loaded
1/4 wave antenna that is only 56" long which is bull . Just like some other
adds that claim their antenna is a 5/8 antenna wound on a fiberglass rod
only 5' tall now go figure, I guess some also believe this .




"'Doc" wrote in message ...


BuckEye,
But all antennas are 'matched', be they exactly a 1/4 wave
length long, or 75 feet long, or 1 inch long. I'm assuming
that you mean impedance matching, right? Impedance matching
has nothing to do with an antenna being resonant.
'Doc

Hrm.. ever stop to think that maybe the wire helically wound around
the shaft might be 1/4 wave long? That would make it a 1/4 wave
helically loaded antenna. Just because the physical length of the
antenna is less than 1/4 wave at the desired frequency doesn't mean
the antenna isn't.

Don't believe me? Try looking up "folded dipole" on the 'net..

-SSB

BuckEye wrote:

What the hell do you think I am saying.
This all started when some dumass said a antenna was electrically 1/4 wave
long, not 1/4 wave antenna. You either have a 1/4 wave antenna or you
don't. If its shorter, then its not a 1/4 wave antenna. In most cases it
loaded, and no more electrically a 1/4 wave long antenna.
How hard is this to understand. I think this comes from some adds that's
states it a helical loaded
1/4 wave antenna that is only 56" long which is bull . Just like some other
adds that claim their antenna is a 5/8 antenna wound on a fiberglass rod
only 5' tall now go figure, I guess some also believe this .




"'Doc" wrote in message ...


BuckEye,
But all antennas are 'matched', be they exactly a 1/4 wave
length long, or 75 feet long, or 1 inch long. I'm assuming
that you mean impedance matching, right? Impedance matching
has nothing to do with an antenna being resonant.
'Doc

In rYlob.66399$Tr4.188400@attbi_s03, "BuckEye" wrote:

What the hell do you think I am saying.
This all started when some dumass said a antenna was electrically 1/4 wave
long, not 1/4 wave antenna. You either have a 1/4 wave antenna or you
don't. If its shorter, then its not a 1/4 wave antenna. In most cases it
loaded, and no more electrically a 1/4 wave long antenna.
How hard is this to understand. I think this comes from some adds that's
states it a helical loaded
1/4 wave antenna that is only 56" long which is bull . Just like some other
adds that claim their antenna is a 5/8 antenna wound on a fiberglass rod
only 5' tall now go figure, I guess some also believe this .

Gee, so you finally read a book and discovered that you were wrong. Fine. But
playing semantics in order to save face is a Twistedhedism.






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BuckEye,
Hi. 'Dumass' here. Like it or not, antennas can and are
classified and/or described by their 'electrical' length.
Electrical length and physical length don't have to be the
same and seldom are when speaking about 'loaded' antennas.
When you find your self in a situation where everyone else
seems to be wrong, and only you are right, it sometimes helps
to stop and re-evaluate your position. Is it mandatory that
you think about antennas the same way I do? Nope, sure isn't,
but it does help if you at least understand 'where' the other
person is coming from, or talking about. It always helps to
view things from a different perspective. When you don't, the
loss is yours...
'Doc

On Fri, 31 Oct 2003 05:35:36 -0600, 'Doc wrote:



BuckEye,
Hi. 'Dumass' here. Like it or not, antennas can and are
classified and/or described by their 'electrical' length.
Electrical length and physical length don't have to be the
same and seldom are when speaking about 'loaded' antennas.
When you find your self in a situation where everyone else
seems to be wrong, and only you are right, it sometimes helps
to stop and re-evaluate your position. Is it mandatory that
you think about antennas the same way I do? Nope, sure isn't,
but it does help if you at least understand 'where' the other
person is coming from, or talking about. It always helps to
view things from a different perspective. When you don't, the
loss is yours...
'Doc

Doc;
I think he was calling me the dumbass, not you.
At first I just thought he didn't understand the theory that was being
posted here and wanted to learn. Hopefully he won't have the same
problems reading a book. Like you said his loss.

In , 'Doc wrote:

snip
When you find your self in a situation where everyone else
seems to be wrong, and only you are right, it sometimes helps
to stop and re-evaluate your position.

Wise words for anyone in a similar predicament, and especially for certain
paranoid individuals who incorrectly perceive the situation as some sort of
newsgroup conspiracy.






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