Question on antenna symantics
 

Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less).I am saying this should be called an 1/8 wl antenna
though I am arguing with those who generally know more more about this than
I. Not all the old timers disagree with me, so I am betting this is a pretty
common problem when discussing antennas.

"Jimmy" wrote in message
.com...
Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less).I am saying this should be called an 1/8 wl antenna
though I am arguing with those who generally know more more about this
than
I. Not all the old timers disagree with me, so I am betting this is a
pretty
common problem when discussing antennas.

You have to differentiate between electrical length and physical length.
Electrically, the antenna is a 1/4 wavelength antenna. Physically it is
0.125 wavelength tall.
Then again , you could do what the CB industry does and measure the length
of the wire and call it, say, a 1 wavelength antenna- meaningless.
Dale W4OP

In article , Jimmy wrote:
Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna
if it is physically only 4ft long or would this be an 1/8 wavelength

If the antenna is an electrical 1/4 wave then it is a 1/4 wave antenna, even
if it is physically shortened by use of coils.


Alex / AB2RC

Jimmy wrote:

Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less).I am saying this should be called an 1/8 wl antenna
though I am arguing with those who generally know more more about this than
I. Not all the old timers disagree with me, so I am betting this is a pretty
common problem when discussing antennas.

What you have is a *physically* short antenna that is *electrically*
1/4WL long. This usually involves a loading coil.

Also, the electrical length of a piece of coax is longer than it's
physical length because of the velocity factor less than 1.0.
--
73, Cecil http://www.qsl.net/w5dxp



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Jimmy,

I hope I am not providing flame fodder by saying you can call it several
things, but I believe this is certainly the case. I think "we" are all too
eager to engage in a symantics war rather than aiding to the understanding
of the OP.

What you see in this thread is that there are different ways of
describing the same thing and a netnews group is just about the best place
to find all those different ways. Based upon the way we each learned about
something, our method of discussing them is colored. There are frequently
several "mental models" which suffice for one physical thing.

*** Many of the posters understand, in their own way, what is going on, but
terminology can get complex and in the way sometimes. You will have to
develop the best "mental model" that works for you. Terminology will also
change over time in some areas.

Digression side bar:
The "J" antenna has come to be called the "J-Pole". "J-Pole" was a product
name for a commercial product with several "J" elements stacked on a
vertical "Pole" for gain. Odd. Nonetheless, I have become accostumed to
this and know what they mean. They also talk about "Wide band receive"
these days. "Wide band" used to refer to the bandwidth of the receiver's
IF as in wide band FM and narrow band FM. Now the term is used in place of
"General Coverage" receive.
End side bar:

If you are explicit in your description so the reader/listener knows what
you wish to talk about, you will be better off than trying to "latch on" to
one and only one "right" terminology. Then try your best not to get into
the symantic battles, but discuss the specifics.

Let's take your initial description:
Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less)
What to call it?

First, when you say "4ft long", preceeded by "...still a 1/4
wavelength..." we must decide just what the antenna is. Since you say
"still" 1/4 wavelength, you seem to be talking about a vertical which
"should be" a 1/4 wave, but we took out the clippers and it has been
shortened and is not physically 1/4, but half that length or 1/8 wave long.

Because you say "resonant", this tells us that something must have been
done to get it to resonate (take away the reactive part) since the 1/8 wave
is not resonant by itself. Therefore we can state that we do have an 1/8
wave radiator and a matching "thing" perhaps a loading coil. "Loading coil"
being the terminology we use to call a series (but not always) coil
somewhere on the antenna.
Because we have now made it resonate (by virtue of the addition of the
loading coil, or whatever) It is looking, from the transmitter or coax,
more like the full 1/4 wave physical length antenna -- because a REAL 1/4
wave hunk of iron-in-the-sky would also be resonant by itself.. From this
we can consider that it is now "Electrically" a 1/4 wave antenna, because
from the "electrical" point of view (that is from inside the coax and
"looking at the antenna" as a signal from the transmitter would) it appears
to be resonant (just like a 1/4 wave antenna).

Be careful with this "electrical" and "physical" talk. I have read threads
here where it gets very confusing with these two terms sprinkled
throughout -even when I'm familiar with the antenna under fire..

Now, doing the usual digression to a related, but not asked question...
The radiation pattern _WILL_ be that of the physical stuff in the air.
(this assumes that the loading / matching device is not a significant part
of the stuff doing the radiation -- not all that unreasonable of an
assumption). In this case, it radiates like an 1/8 wave antenna.
Unfortunately, an 1/8 wave isn't much different than the 1/4 wave ... thus
allowing more discuccion as to whether or not it is 1/4 or 1/8. ...more
digression... What I'm cautioning you about here is that it is the physical
antenna that determines the _radiation pattern_ and you can't get full-size
antenna performance with a smaller antenna and some magical circuit tricks
or matching tricks, or some yet undiscovered, super quantum theory based
wiggles on teh feed line of elements. You may get a pretty good antenna,
but it is the Iron-in-the-sky that makes a pattern...un-digress...

SO, what to call it?
My initial vote would be to start with "loaded 1/8 wave vertical". This
describes the physical antenna (a not optimim one) , then what was done to
make it work better. I think calling it a 1/4 wave antenna is misleading
for most people. You, not I, can take a vote what is brought to mind if you
just say it is a "1/4 wave vertical". I'll bet most will think _1/4 wave
physical_.

You can go further and describe the loading system furtherlike:
Center loaded, 1/8 wave vertical.antenna.
Base loaded, 1/8 wave vertical.antenna.
Top loaded, 1/8 wave vertical.antenna.
Shortened, 1/4 wave vert doesn't do too badly...

Then there's the "counterpoise" to consider. If you strung radials at the
bottom "1/8 wave ...ground plane" is in order. If not, then "ground
mounted 1/8 wave ..." may be called for.

In other words...describe it well and there should be less misunderstanding
as to just what your subject is.

OK flamers, knock yourself out...
--
Steve N, K,9;d, c. i My email has no u's..










"Jimmy" wrote in message
.com...
Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less).I am saying this should be called an 1/8 wl antenna
though I am arguing with those who generally know more more about this
than
I. Not all the old timers disagree with me, so I am betting this is a
pretty
common problem when discussing antennas.

On Tue, 20 Jan 2004 20:19:39 GMT, "Jimmy"
wrote:

Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less).I am saying this should be called an 1/8 wl antenna
though I am arguing with those who generally know more more about this than
I. Not all the old timers disagree with me, so I am betting this is a pretty
common problem when discussing antennas.

A 1/2 wave dipole on 10 meters is about 16 feet. So 4 feet sounds like
1/8 wavelength, physically, to me.

Unless it has a loading coil -- which could make it, electrically,
"longer" than 1/8 wavelength.

Bob
k5qwg

Steve,
All things considered, I don't see how your post can be
flamed. In fact, it's one of the better discriptions I've
ever seen (meaning I'm gonna steal it!).
'Doc

Jimmy, I don't see the connection between "resonant" and "1/4-wavelength",
at least from what you posted. And, in this universe, 4 ft. is NOT 1/4 on
10 meters...

- KI6PR
El Rancho R.F., CA

"Jimmy" wrote
Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less).I am saying this should be called an 1/8 wl antenna
though I am arguing with those who generally know more more about this
than
I. Not all the old timers disagree with me, so I am betting this is a
pretty
common problem when discussing antennas.

If the antenna is an electrical 1/4 wave then it is a 1/4 wave antenna, even
if it is physically shortened by use of coils. Alex / AB2RC


If that is true, then there is no such thing as a 5/8 wave antenna. They
would be 3/4 wave antennas.

Don't think so. 73 Al Lowe N0IMW

In article , Arrow146 wrote:
If the antenna is an electrical 1/4 wave then it is a 1/4 wave antenna, even
if it is physically shortened by use of coils. Alex / AB2RC


If that is true, then there is no such thing as a 5/8 wave antenna. They
would be 3/4 wave antennas.

since when does 5/8 = 3/4 ?
last time I checked, 3/4 = 6/8




Don't think so. 73 Al Lowe N0IMW

"Cecil Moore" wrote in message
...
Jimmy wrote:

Is an antenna that is resonant on 10 meters still a 1/4 wavelength
antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less).I am saying this should be called an 1/8 wl
antenna
though I am arguing with those who generally know more more about this
than
I. Not all the old timers disagree with me, so I am betting this is a
pretty
common problem when discussing antennas.

What you have is a *physically* short antenna that is *electrically*

Does this mean that I can call a 5/8 antenna a 3/4? I would think it should
be one way or the other. I was really hoping for a more definative answer
than I have gotten here so far as there is a signiificant quantity of beer
at stake. I know what I have I just want someone to settle the argument on
what it should be called. In other words, should we use physical length or
electrical length to describe an antenna. It is my opinion that antennas
should be referenced by there physical length otherwise we will be giving
creedance to those who are trying to sell 5/8wl antennas that are physically
only an 1/8wl long.

1/4WL long. This usually involves a loading coil.

Also, the electrical length of a piece of coax is longer than it's
physical length because of the velocity factor less than 1.0.
--
73, Cecil http://www.qsl.net/w5dxp



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"Arrow146" wrote in message
...
If the antenna is an electrical 1/4 wave then it is a 1/4 wave antenna,
even
if it is physically shortened by use of coils. Alex / AB2RC


If that is true, then there is no such thing as a 5/8 wave antenna. They
would be 3/4 wave antennas.

Don't think so. 73 Al Lowe N0IMW
Al, This was the basis of my thoughts on the subject too, Im the OP. Im of
the opinion an antenna shorter than 1/4 wll should either be identified by
its fractional wl dimension or as a loaded x freq antenna y units long.
Otherwise those who advertise 5/8 antennas that are physically 1/8wl long
have every right to do so.

To avoid misunderstandings, which often end up in vicious arguments, there
is no alternative but to think about it and say exactly what you mean.

Then read what you have written and think AGAIN.

Avoid old-wives' jargon.

Have a free program.
----
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........

The radiation patterns for a 1/4 and a loaded 1/8 wave should be
slightly different.

If so, ERGO! Two different antennas.

Boy, this stuff is tough! :-)

Jimmy wrote:

Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less).I am saying this should be called an 1/8 wl antenna
though I am arguing with those who generally know more more about this than
I. Not all the old timers disagree with me, so I am betting this is a pretty
common problem when discussing antennas.

Alex Flinsch wrote in message ...
In article , Arrow146 wrote:
If the antenna is an electrical 1/4 wave then it is a 1/4 wave antenna, even
if it is physically shortened by use of coils. Alex / AB2RC


If that is true, then there is no such thing as a 5/8 wave antenna. They
would be 3/4 wave antennas.

since when does 5/8 = 3/4 ?
last time I checked, 3/4 = 6/8

A 5/8 ground plane is tuned to a 3/4 wave resonance.
Myself, I think they should be described as their actual physical
length. That gives you a better idea of their true performance. If you
called a 5/8 antenna , a 3/4 wave, in my mind, the gain on the horizon
drops and higher angle lobes start to appear...Then you have the cases
of the "short" 1/2 waves...The shorty versions will never have the
gain that a true full size half wave will. Calling them 1/2 waves is
misleading. When I talk about my 10 ft tall mobile antenna, it's a 1/4
wave resonance anywhere I tune the antenna. But I don't go around
calling it a 1/4 wave...I call it a 10 ft center loaded vertical. In
my book, to be called a 1/4 wave, it needs to actually be a 1/4 wave
in physical length. I'd call his antenna, a 1/8 wave tall loaded
vertical.
MK

If that is true, then there is no such thing as a 5/8 wave antenna. They
would be 3/4 wave antennas.

since when does 5/8 = 3/4 ?
last time I checked, 3/4 = 6/8


Sense always.
A two meter 5/8 wave length (48") whip does not work
very well. A 3/4 wave length whip will tune
up fine (low SWR) but has a very high angle
of radiation, still does not work well.

Take 1/8 wave (about 9 1/2 inches) of the
3/4 wave and turn it into a coil. And you
end up with an antenna about 48" tall that works
real well. (5/8 wave = 48")

I guess if you want to follow the CB Hipe about
antennas, it's up to you.

You think a 3 ft. 11 meter antenna that claims to
be of 5/8 wave antenna, works like a true 5/8 wave
length Antenna - - I think I will stop here.

I have a lot more important things I should be doing.
Arrow Antenna lost its lease on our building, wo we
had to move. I have a lot of equipment to get hooked
up again so we can get back into the production of
real antennas.

73 Al Lowe N0IMW
ArrowAntenna.com
911 East Fox Farm Road. #2
Cheyenne, WY 82007

307-638-2369
Fax 307-638-3521

Thanks Bill. I was worried more about the (hopefully mild) attacks on the
propensity to nit pick on words or (what almost seems like intentional) mis
understanding due to the way terminology is used.

I haven't read all the other posts yet, but I made the decision to ignore
this detail (loaded ant feed Z) since it didn't help the naming problem. I
really try to address the OP's question without clouding it with other
probably true, but very possibly confusing details.

Of course, there is no guarantee that the loading coil actually does get you
to a zero reactance, thought we like to think we can do that -- and that
was my assumption. I think I said, or at least wanted to imply that we try
to get back to a zero reactance (a.k.a. resonance) and _that_ is "just like"
the "real" 1/4 wave....and therefore, perhaps, that is why some may want to
call it a 1/4 wave, but I am guessing what others think. I don't know who
wanted to call it a 1/4 wave in the previous posts.

--
Steve N, K,9;d, c. i My email has no u's.


"Bill Turner" wrote in message
...
On Tue, 20 Jan 2004 17:48:28 -0600, "Steve Nosko"
wrote:

...[ gobs'n gobs snipped]
__________________________________________________ _______

An excellent explanation, Steve, but needing one correction. When
adding a loading coil as above, the feed point resistance drops
significantly, so it no longer appears to be "just like a 1/4 wave
antenna".

Otherwise, great post.

For the benefit of the original poster, the word is "semantics".

--
73, Bill W6WRT

Mikey,

You'll have to read more of the other posts. I particularly recommend
mine.

"Steve Nosko" wrote in message
...

If it is gone, I can re-post

--
Steve N, K,9;d, c. i My email has no u's.

"Mikey" wrote in message
...
Jimmy, I don't see the connection between "resonant" and "1/4-wavelength",
at least from what you posted. And, in this universe, 4 ft. is NOT 1/4 on
10 meters...

- KI6PR
El Rancho R.F., CA

"Jimmy" wrote
Is an antenna that is resonant on 10 meters still a 1/4 wavelength
antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less).I am saying this should be called an 1/8 wl
antenna
though I am arguing with those who generally know more more about this
than
I. Not all the old timers disagree with me, so I am betting this is a
pretty
common problem when discussing antennas.

WHOA!! Now, you didn't mention the beer before. Let me know if my
explanation helped...and what my cut of the beer is. I pasted the message
ID if it is gone, or I can re-post.

--
Steve N, K,9;d, c. i My email has no u's.


"Steve Nosko" wrote in message
...


"Jimmy" wrote in message
. com...

"Cecil Moore" wrote in message
...
Jimmy wrote:

Is an antenna that is resonant on 10 meters still a 1/4 wavelength
antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less).I am saying this should be called an 1/8 wl
antenna
though I am arguing with those who generally know more more about this
than
I. Not all the old timers disagree with me, so I am betting this is a
pretty
common problem when discussing antennas.

What you have is a *physically* short antenna that is *electrically*

Does this mean that I can call a 5/8 antenna a 3/4? I would think it
should
be one way or the other. I was really hoping for a more definative answer
than I have gotten here so far as there is a signiificant quantity of beer
at stake. I know what I have I just want someone to settle the argument on
what it should be called. In other words, should we use physical length or
electrical length to describe an antenna. It is my opinion that antennas
should be referenced by there physical length otherwise we will be giving
creedance to those who are trying to sell 5/8wl antennas that are
physically
only an 1/8wl long.

1/4WL long. This usually involves a loading coil.

Also, the electrical length of a piece of coax is longer than it's
physical length because of the velocity factor less than 1.0.
--
73, Cecil http://www.qsl.net/w5dxp



-----= Posted via Newsfeeds.Com, Uncensored Usenet News =-----
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Arrow,
One of those important things might be to explain to
me how 9 1/2" is a 1/8 wave at what frequency? I thought
we were talking 10 meters...
'Doc

Perhaps this should be another thread, but digression is the order of the
day here on Usenet... SO, Steve continues.


"Electrical vs. physical length of an antenna." I am going to pick on
this bone here and stick my neck out. Correct me if I'm wrong (Like I have
to say that here...) I think there are two posters, Alex and Cecil who
used the term "electrical Length" in reference to antennas (copied below)
and like its correctness. I haven't personally focused on this use of the
term until now because I knew what was _meant_ when it was used, but after
some thought I feel this is a very misleading use of the term. Particularly
for the beginner. Here goes...

In a previous post, I talked about a "physically short" antenna that was
then "tuned" by adding some kind of a "loading" device. Here, "physically
short" means that it is shorter than: some other length, which ,
naturally has no reactive drive impedance. A half wave dipole, that we are
all familiar with, being the simplest to understand. This is what I am
calling a "natural length" antenna which has no reactance in its drive
impedance.
This antenna _IS_ a half wave long (don't nit pick about end effects,
etc., please) It naturally resonates - by this we all (I hope) mean that it
looks all real with no reactance - or zero phase between V and I.
NOW, we cut some off the antenna and "shorten" it. It is no longer 1/2
lambda long.
Whoa! it has some reactive part in the drive Z. AND it ain't the usual
72 ohms, or whatever, for the real part either. !

Cripes ! now what do we do ? (obviously inserting the rhetorical
question). We all know that an antenna Z just has to be all real, right?
Well that's another thread, because it doesn't have to be, but let's shelve
that one for later. Let's say that we REALLY want an all resistive drive Z,
and that's ok. Well, being experts in using one reactance to cancel
another, we just put another with the opposite sign in series and
presto...all resistive. DONE.

OOPS The real part ain't 72 ohms anymore! WA-HAPPEN" ?? Well, most of you
know. This shortened antenna ain't 72-jx ohms when we cut it up, it went to
something like 40-jx ohms and all we sis was strip off the -jX to leave the
40 ohms real.

So let's look at this. We now have an antenna that is certainly not a 1/2
wavelength long any more RIGHT???

AND... to make matters worse...

The real part we wound up with ain't 72 ohms any more either, RIGHT ??

SO how in blazes can we say that this, in any way, shape or form resembles
a 1/2 wave antenna !huh? huh! tell me, huh?

Well, the only way is that we got it to be "resonant". and the 1/2 wave is
resonant.... Well, that doesn't work with the mental model I have in my
brain, buster.

Someone might like to say that we took the wire we cut off and wound it up
into a coil and stuck it back on, so we still have a 1/2 wave total. Except
my extremely educated and experienced (not to mention arrogant) gut tells me
that you're going to have quite a bit of wire left over when you get all the
X out. So there must be more to the story.

WAIT ! WAIT ! you say. Do we _NOT_ talk about electrical length and
physical length when on the subject of transmission lines, huh? huh? say it
now...we DO don't we? you can't deny it, can ya?....

Hold on there partner, I say. You're mixing your apple basket with the
bananas. There's a glitch in the nomenclature soup.
Chew on this for a while. Transmission line has a physical length, yes, but
measured in feet, inches and the like....right. This is a physical length
measured in the 3 dimensional space we all have grown to know and love.

HOWEVER, transmission line has electrical length measured in ...fanfare
please... DEGREES. Degrees ain't a length. We can equate it to some
ruler length, but that is not what we are after in this case. Well, we know
that we need to be talking about the wavelength of our signal when it is in
the transmission line. That is what matters, not the physical length,
because the wave length in the transmission line is shorter than in air. We
need to know where on the _wave_ we are, because we are concerned about
phase at this point. So we CAN relate a specific PLACE on the line which
gets us to the Phase we want.

Now for the final muddy water exercise...

If we desire to keep this term and use it consistently, then we must talk
about the electrical length in _degrees_, no?
BUT, BUT, BUT you say... half a wave length is 180 degrees, so therefore it
is ok to use the wavelengths measure for this thing called "electrical
length".

OK, lets go there... Lets talk about what we could call an "electrical
length" for this antenna. How many _degrees long_ is the aforementioned
shortened antenna?
Just so you are sure to know: Here's the final mud.

What two points are YOU going to use for this "Electrical length" In other
words; Just what is the antenna?...The radiator only? The radiator AND the
coil. Does the coil radiate, is it or is it not part? Take your pick.

In other words, this is a highly questionable and indefinite and confusing
way to talk about an antenna. I don't think "electrical length" should be
used for an antenna. I don't think it makes sense because you are really
talking about, in the first approximation, whether you have gotten back to
you favorite place called resonance --nothing more -- - which has nothing to
do with length, but rather impedance matching with (usually) lumped
elements. And besides, how do you KNOW with 100% certainty that this
"shortened 1/2 wave" [let's say a 32 ft dipole on 40M] has been
"lengthened" (by use of loading coils) to 1/2 wave length rather than, say
oh, I don't know...3/2 "electrically"??

[[yea, yea. I know there has been a never ending thread on here about what's
going on in the antenna loading coil---current at the ends, phase and
probably a zillion other things with words flying all about]]

For a transmission line it is all very clear. For antennas, there are miles
of room for confusion so my vote is to - cut that out with the beginners


My brain hurts--why do I do this....
--
73, Steve N, K,9;d, c. i My email has no u's.

The two posts in question
=============================
In article , Jimmy wrote:
Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna
if it is physically only 4ft long or would this be an 1/8 wavelength

If the antenna is an electrical 1/4 wave then it is a 1/4 wave antenna, even
if it is physically shortened by use of coils.


Alex / AB2RC
================================

"Cecil Moore" wrote in message
...
Jimmy wrote:

Is an antenna that is resonant on 10 meters still a 1/4 wavelength
antenna
if it is physically only 4ft long or would this be an 1/8 wavelength
antenna(more or less).I am saying this should be called an 1/8 wl
antenna
though I am arguing with those who generally know more more about this
than
I. Not all the old timers disagree with me, so I am betting this is a
pretty
common problem when discussing antennas.

What you have is a *physically* short antenna that is *electrically*
1/4WL long. This usually involves a loading coil.

Also, the electrical length of a piece of coax is longer than it's
physical length because of the velocity factor less than 1.0.
--
73, Cecil http://www.qsl.net/w5dxp

Steve Nosko wrote:
And besides, how do you KNOW with 100% certainty that this
"shortened 1/2 wave" [let's say a 32 ft dipole on 40M] has been
"lengthened" (by use of loading coils) to 1/2 wave length rather than, say
oh, I don't know...3/2 "electrically"??

One looks at the current distribution. The current at the end of a
wire is zero. 1/4 electrical wavelength (90 degrees) back from the
end of the wire, the current is at its maximum. That's at the lowest
purely resistive point. If that point is on the antenna, it is
electrically 90 degrees from the end of the antenna. If that point
is on the transmission line, it is electrically 90 degrees from the
end of the antenna.
--
73, Cecil, W5DXP

Someone sed:

"In my book, to be called a 1/4 wave, it needs to actually be a 1/4 wave
in physical length."

==================

Yes! HELL yes.

(But then there's that darn Slinky."

73 e Jack, K9CUN

But you have to remember that a 5/8 lamda whip is really trying to be a
1.25-lambda dipole with half of the dipole kind of provided by the perfect
conductor infinite ground plane.

Just like a 1/4-lambda whip (vert) is similarly "equivalent" to a vertical
1/2-wave antenna.

A 1.25-lambda doublet (I won't call it a dipole for obvious reasons) has a nice
broadside gain over a 1/2-wave dipole.

Hey, if you orient it vertical, you have an omnidirectional "beam".

"Load your downspout!"

Jack, K9CUN

Arrow,
One of those important things might be to explain to
me how 9 1/2" is a 1/8 wave at what frequency? I thought
we were talking 10 meters...
'Doc

Hello, Doc
As quoted below 2 meters (146 MHz.)
I use two meters because I have all the numbers in
my head, I don't have to use a calculator.
I don't make 10 meter antennas.

73 Al Lowe N0IMW

A two meter 5/8 wave length (48") whip does not work
very well. A 3/4 wave length whip will tune
up fine (low SWR) but has a very high angle
of radiation, still does not work well.

Take 1/8 wave (about 9 1/2 inches) of the
3/4 wave and turn it into a coil. And you
end up with an antenna about 48" tall that works
real well. (5/8 wave = 48")

On Tue, 20 Jan 2004 20:19:39 GMT, "Jimmy"
wrote:

Is an antenna that is resonant on 10 meters still a 1/4 wavelength antenna
if it is physically only 4ft long

No.

or would this be an 1/8 wavelength
antenna(more or less)

Close enough to say Yes.

I am saying this should be called an 1/8 wl antenna
though I am arguing with those who generally know more more about this than
I. Not all the old timers disagree with me, so I am betting this is a pretty
common problem when discussing antennas.

Hi Jimmy,

If it wasn't before, it sure is now.

The description is the physical size in the applied frequency's
wavelength.

Skip all the sophistries based on resonance because at 10M that could
lead to a foot long loaded resistor being called a 107/4th's
wavelength antenna. (After the first couple of "electrical"
quarterwaves, why stop? Resonance certainly cannot tell which
quarterwave it is at.) The only way to distinguish successive, odd
quarterwavelength antennas is in their radiation resistance which
accumulates with SIZE, not components (unless you are stringing
resistors like christmas tree bulbs). Even then, the cumulative
resistance does not add beyond the 3rd or 5th quarter.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote in message
...
On Tue, 20 Jan 2004 20:19:39 GMT, "Jimmy"
wrote:

Is an antenna that is resonant on 10 meters still a 1/4 wavelength
antenna
if it is physically only 4ft long

No.

or would this be an 1/8 wavelength
antenna(more or less)

Close enough to say Yes.

I am saying this should be called an 1/8 wl antenna
though I am arguing with those who generally know more more about this
than
I. Not all the old timers disagree with me, so I am betting this is a
pretty
common problem when discussing antennas.

Hi Jimmy,

If it wasn't before, it sure is now.

The description is the physical size in the applied frequency's
wavelength.

Skip all the sophistries based on resonance because at 10M that could
lead to a foot long loaded resistor being called a 107/4th's
wavelength antenna. (After the first couple of "electrical"
quarterwaves, why stop? Resonance certainly cannot tell which
quarterwave it is at.) The only way to distinguish successive, odd
quarterwavelength antennas is in their radiation resistance which
accumulates with SIZE, not components (unless you are stringing
resistors like christmas tree bulbs). Even then, the cumulative
resistance does not add beyond the 3rd or 5th quarter.

73's
Richard Clark, KB7QHC
For what it is worth I got the beer.

Jimmy,

What did you call it to get the beer?

--
Steve N, K,9;d, c. i My email has no u's.


"Jimmy" wrote in message
...

"Richard Clark" wrote in message
...
On Tue, 20 Jan 2004 20:19:39 GMT, "Jimmy"
wrote:

Is an antenna that is resonant on 10 meters still a 1/4 wavelength
antenna if it is physically only 4ft long

For what it is worth I got the beer.

"Steve Nosko" wrote in message
...
Jimmy,

What did you call it to get the beer?

--
Steve N, K,9;d, c. i My email has no u's.


"Jimmy" wrote in message
...

"Richard Clark" wrote in message
...
On Tue, 20 Jan 2004 20:19:39 GMT, "Jimmy"
wrote:

Is an antenna that is resonant on 10 meters still a 1/4 wavelength
antenna if it is physically only 4ft long

For what it is worth I got the beer.



We agreed that it should be identified by its physical length