On Sun, 2 Apr 2006 22:54:10 -0400, "Yuri Blanarovich"
wrote:

They might say "60 degree top loaded resonant radiator" but they don't
say "60 degree tall radiator 90 degree resonant".

If you stick the coil at the base in series with radiator and bring it to
resonance (zero reactance at the frequency of interest) what "degree
resonant" will than radiator become, if not 90? ("Measured" from the feed
point, through the coil and then straight radiator.)

Hi Yuri,

This must be a convention that is particular to only a very few Hams.
The FCC database describes AM antennas in both electrical and physical
height as follows.

WGOP 80.00° tall 125.2 meters tall 540 kHz
WWCS 63.50° tall 98.8 meters tall 540 kHz
WFTD 79.00° tall 64.0 meters tall 1080 kHz
KYMN 118.60° tall 92.3 meters tall 1080 kHz
WWLV 90.00° tall 47.2 meters tall 1620 kHz
WTAW 204.00° tall 106.7 meters tall 1620 kHz

There may be some discrepancy, but it certainly looks like antenna
specification is by the electrical equivalent of the physical height
(and whatever l/d fudging) and with only one happening to be 90°.

Further, given most references (for professionals) is aimed at a
common specification that is largely driven by this agency, it would
seem odd to step out of this expectation to change to calling all
antennas 90° simply because they resonate.


http://www.fcc.gov/mb/audio/amq.html

73's
Richard Clark, KB7QHC

"Richard Clark" wrote
This must be a convention that is particular to only a very few
Hams. The FCC database describes AM antennas in both
electrical and physical height as follows. .... it would seem
odd to step out of this expectation to change to calling all
antennas 90° simply because they resonate.
_____________

The FCC data cited does not include the reduced velocity of propagation
along the radiator -- which means that an FCC "90 degree" radiator is not
resonant, it has some inductive reactance. A network is used at the
radiator feedpoint to transform the complex impedance there to properly
match the transmission line.

That "90 degree" radiator would need to be shortened by several percent in
order to be self-resonant. Kraus (3rd Ed, p 182) shows a feedpoint Z of 73
+ j42.5 ohms for a thin-wire, linear dipole that is a physical
1/2-wavelength, and that self-resonance occurs at a length a few percent
shorter, when the radiation resistance drops to about 65 ohms.

An unloaded 1/4-wave MW broadcast monopole working against the typical
broadcast radial ground system has about 1/2 the impedance that Kraus shows
for a dipole in free space.

RF

"Richard Clark" wrote Hi Yuri,

This must be a convention that is particular to only a very few Hams.
The FCC database describes AM antennas in both electrical and physical
height as follows.

WGOP 80.00° tall 125.2 meters tall 540 kHz
WWCS 63.50° tall 98.8 meters tall 540 kHz
WFTD 79.00° tall 64.0 meters tall 1080 kHz
KYMN 118.60° tall 92.3 meters tall 1080 kHz
WWLV 90.00° tall 47.2 meters tall 1620 kHz
WTAW 204.00° tall 106.7 meters tall 1620 kHz

There may be some discrepancy, but it certainly looks like antenna
specification is by the electrical equivalent of the physical height
(and whatever l/d fudging) and with only one happening to be 90°.

Further, given most references (for professionals) is aimed at a
common specification that is largely driven by this agency, it would
seem odd to step out of this expectation to change to calling all
antennas 90° simply because they resonate.


http://www.fcc.gov/mb/audio/amq.html

73's
Richard Clark, KB7QHC


That's fine, no argument there. But do you agree that there are towers of X
height in meters and when "naked" having Y electrical degrees, loaded with
top hat of size S, not changing the physical height, but adding Z degrees.
So the top hat adds some degrees to the tower.
Is it such ham radio crime to say that coil can do that too, if it is
inserted within the radiator?
We use imaginary lumped inductor to understand coils better, but we can not
use electrical degrees to 'splain the behavior of coiled antenna wire?
I think we are progressing into antenna modeling and design and I see
nothing wrong with using degrees to describe electrical properties
(resonance) of the loaded radiator.

73 Yuri, K3BU

actually
WWLV 90.00° tall 47.2 meters tall 1620 kHz
should show closer to 92 deg. and assuming that they use fatter tower, even
more.

On Mon, 3 Apr 2006 10:36:45 -0400, "Yuri Blanarovich"
wrote:

So the top hat adds some degrees to the tower.

Hi Yuri,

This is simply new wine in an old bottle. The same FCC site contains
top loaded antennas too. If you can find an example to support your
thesis, you will still have an obscure usage.

73's
Richard Clark, KB7QHC

but we can not
use electrical degrees to 'splain the behavior of coiled antenna wire?

I can see how problems could arise going by the length of coil
wire length in degrees only. Lets say you run a coil 1 foot from the
base. Lets say that coil uses 25 turns to tune a particular frequency.
Now, move the coil up 2 ft higher, and see if that same 25 turns will
tune the same frequency. It won't. You will have to add a few more
turns.
So just going by the total mast plus coil wire length in degrees could
vary
all over the map just by changing the position of the coil. As you
raise
the coil, you will have to add more and more of "degrees" of wire to
tune the same frequency. :/
Dunno...There may well be some variation of current from the bottom
vs the top of the coil, but overall, I still view the operation of a
loading
coil as a "lumped" mechanism overall.
Even if you all decide that the current changes, or it doesn't , it
ain't
gonna make a hoot's worth of difference in the design of mobile whips.
I think it's an argument that has no real value to me as far as mobile
whips go. The performance of all the various coil heights, and configs
have been well known for years. Coil current taper or not.
I just don't see the facination with arguing about something that even
if
decided one way or the other, still won't make any difference in the
final
antenna design. Oh well...Continue the tail chasing excercise....
I'm outa this one... One post is all I will waste on this subject..
I couldn't mount my coil much higher if I wanted to... Current taper or
not. :/
MK

wrote:
I just don't see the facination with arguing about something that even
if
decided one way or the other, still won't make any difference in the
final
antenna design.

The sun still rises every morning whether it is caused by
the earth's rotation or by the Sun God riding his chariot
across the sky. The facination is called technical correctness.
--
73, Cecil http://www.qsl.net/w5dxp

wrote in message
ups.com...
but we can not
use electrical degrees to 'splain the behavior of coiled antenna wire?

I can see how problems could arise going by the length of coil
wire length in degrees only. Lets say you run a coil 1 foot from the
base. Lets say that coil uses 25 turns to tune a particular frequency.
Now, move the coil up 2 ft higher, and see if that same 25 turns will
tune the same frequency. It won't. You will have to add a few more
turns.
So just going by the total mast plus coil wire length in degrees could
vary
all over the map just by changing the position of the coil. As you
raise
the coil, you will have to add more and more of "degrees" of wire to
tune the same frequency. :/
Dunno...There may well be some variation of current from the bottom
vs the top of the coil, but overall, I still view the operation of a
loading
coil as a "lumped" mechanism overall.
Even if you all decide that the current changes, or it doesn't , it
ain't
gonna make a hoot's worth of difference in the design of mobile whips.
I think it's an argument that has no real value to me as far as mobile
whips go. The performance of all the various coil heights, and configs
have been well known for years. Coil current taper or not.
I just don't see the facination with arguing about something that even
if
decided one way or the other, still won't make any difference in the
final
antenna design. Oh well...Continue the tail chasing excercise....
I'm outa this one... One post is all I will waste on this subject..
I couldn't mount my coil much higher if I wanted to... Current taper or
not. :/
MK


MK, that is the whole point, that you portray missing or not appreciating.
It might not matter to you if you lose $100, but it might matter to someone
else. Same with loading coil. What you are describing, the effect where the
coil is located, being known, is the result of the phenomena we are trying
to straighten out, explain and apply properly in modeling and design
exercises.

The position of coil within the antenna has significant effect. The worst is
at the base, fewer turns required. The best is somewhere about 2/3 up the
radiator, more turns required. You stick it on the top, no stinger or hat,
you get it almost invisible. With what we are discussing and defending here
is the proper understanding of the current flow in the loading coil and its
drop across and its effect on the efficiency of the loaded antenna.
Efficiency is proportional to the area under the current curve distribution
along the radiator. If you properly model the coil as solenoid or loading
stub to see the real drop of current across the coil and its effect in
various positions along the radiator, the all is clear and is with agreement
with practical experience, antenna shootout results, measurements.
As I mentioned numerous times, its effect on design and modeling loaded
antenna systems will be even more pronounced, because effect gets magnified
when you start adding elements. This is especially important when you try to
design super receiving antennas for low bands where F/B and clean pattern is
very desirable and is the most critical aspect of antenna design or
modeling. It is harder to obtain the max F/B or least rear lobes than to
maximize the design for max gain.
It might not matter to you, but I am sure many would benefit from knowing
more precisely what is REALLY going on and then use or correct their design
methodology.
I think it is fine for you to ignore this and poh-poh it. But I know how
huge difference it made in my 160m mobile antenna when I extended the whip
to the front bumper with wire.
We are not saying that piece of wire that coil is wound with, has so many
electrical degrees. If we carefully consider and understand the phenomena,
you would realize that the radiator has same electrical length (say 15 deg)
and when you move the coil and ADJUST THE TURNS to bring the antenna back to
resonance (90 deg) that coil would "replace, take care of" 75 degrees. The
turns have to be adjusted in order to "participate" in the current
replacement game. The lesson is, the higher you place the coil on the
radiator, the more turns you need to reresonate the radiator, the high
current portion of the antenna current distribution curve gets "stretched
up", better efficiency (larger area under the overall curve). Then the coil
DROPS the current across itself to some lower value, which then continues to
drop across the tip and that area, quite smaller adds to the one from the
bottom part of the radiator.
This all is supported by reality, except "gurus" who insist that the current
is (about) the same across the coil and they make (theoretically) antenna
current to be higher across the tip and "more" efficient than it is. Again,
you stick 6 of those in the 3 el loaded Yagi design and you get GI-GO.

It is known how profound effect had replacement of loading stubs by coils in
the KLM 3 el. 80 m loaded Yagi. Better gain, huge improvement in the F/B and
pattern. Has been done and described. And this is just replacing the same
inductance value stub with coil, where delta current from stub wires was
enough to throw monkey wrench in the Yagi performance. Now consider larger
error from the wrong assumption or calculation caused by wrong current
magnitudes and distribution.

Again you might not give a hoot about this "trivial" exercise, but if I want
to design 4 el loaded quad or Yagi for 80 or 160, it matters a lot.
So it just amazes me that some of the smarter heads resist so much in trying
to find out reality and develop better consideration of the effect for
design and modeling. No technical answers to Cecil's questions and my "from
scratch" thread deteriorated into pink electrons and dead end in electrical
degrees.

So far what we have is the reality, few who are trying to legitimize it and
few who got off on the wrong foot, in effort to preserve their (wrong) face
they cling to it with scientwific "proofs" why it can't be so, when IT IS.
When I tried to go step by technical step through the case, the "gurus" are
not there. Cases that Cecil showed in EZNEC model and demonstrating that
current across the loading coil (not one in the box) in the antenna can have
anything from equal to "nothing" at the other end, depending on its position
in the standing wave picture. It all jives with our original argument. We
spotted the "problem", we dissected it, thanks to fierce flat earthers, and
now have better understanding of the phenomena and can use to design better
antennas.
I care about antennas, this is the last frontier where we can still improve
thing, now with modeling tools. I still operate contests and go for
ultimate - beating the all time records, and that's where the edge can be
obtained.

Heloooo guys!
Measure, feel, whatever, the frickin' current across the loading coil and
then come back and tell the world why it IS different, but IT CAN'T be so,
because you said so in the beginning and you just can't admit being wrong.
Reality can't be twisted, just like Earth is not going back to flat!
Saying now that is no big deal, not important, will not exonerate the
"wrongoes". It is significant not to be ignored. If I was in "their" shoes,
I would say: "gee guys, interesting, thanks for bringing it up, explaining
it, I guess we were wrong, now we can design better antennas". Stay
tuned.....

Thanks again Cecil, Richard and others for putting up with and shedding more
and more light on the phenomena. It must go down in history as big as
Galileo's fight :-) I am glad that, hopefully, nobody will burn us.

73 Yuri, K3BU.us

On Tue, 4 Apr 2006 10:32:08 -0400, "Yuri Blanarovich"
wrote:

Now consider larger
error from the wrong assumption or calculation caused by wrong current
magnitudes and distribution.

Hi Yuri,

Why is it that you can say this so often, and yet never put a number
to it?

What is the error? You also speak of efficiency. What is the
efficiency?

Very simple questions. Technically based. Selected because they seem
to be of supreme importance to you, and yet you don't seem to have a
handle on the situation.

73's
Richard Clark, KB7QHC

"Richard Clark" wrote in message
...
On Tue, 4 Apr 2006 10:32:08 -0400, "Yuri Blanarovich"
wrote:

Now consider larger
error from the wrong assumption or calculation caused by wrong current
magnitudes and distribution.

Hi Yuri,

Why is it that you can say this so often, and yet never put a number
to it?


Experience, my dear, experience.
If I am capabl;e of writing to you, I don't have to put number on it, how
many letters of alphabet I master.

What is the error? You also speak of efficiency. What is the
efficiency?

Stick in the EZNEC and find out if you can't sleep without numbers.
Anyone who looks at current distribution curves can see that there is a
difference. No need for lawyers and precise numbers. If only this was the
problem, then I would give you answer to 4 decimal places. You have greater
problem with "gurus" not getting the big picture (or pretending to).

Very simple questions. Technically based. Selected because they seem
to be of supreme importance to you, and yet you don't seem to have a
handle on the situation.

I have the handle on it, appreciate the magnitude and with time there will
be some numbers.
Cecil posted files, anyone who is hang up on numbers can get them from the
EZNEC if properly defined, instead of poking needles.
We are having problem with people admitting there could be difference in the
current across loading coils, and here the "problems" is what is the error?

So lets stick to the big problem and fuggettabout detours and nitpicking.

Yuri, K3BU

73's
Richard Clark, KB7QHC

Yuri Blanarovich wrote:
We are having problem with people admitting there could be difference in the
current across loading coils, and here the "problems" is what is the error?

Actually, the problem is more elementary than coils. Everyone
seems to understand coils installed in circuits.

The ignorance seems to be of the nature of the physics involved
in standing waves, whether on a wire or on a coil or in free
space. So I have switched the discussion to where it belongs,
to a discussion of standing waves, with or without coils,
with or without wires.

I offered the following example which the gurus refuse to touch
with a ten foot pole. One wonders why. The transmission line is
lossless and BB is a black box.

Source-------a-BB-b-----------c-BB-d---------open circuit

The current at 'a' is measured at one amp.
The current at 'b' is measured at zero amps.
The current at 'c' is measured at zero amps.
The current at 'd' is measured at one amp.
What's in the black boxes?

Would you believe ZERO responses from the gurus?
--
73, Cecil http://www.qsl.net/w5dxp