Phase Shift through a 75m Texas Bugcatcher Coil
 

Richard Clark wrote:
Abandon your Xerox ethic and actually read your reference. This
advice would work for other citations you copy off too.

Here's what it says:
"Case 3 uses a model similar to the other two cases, except the
three-segment load wire is replaced by a wire coil ("distributed load")
consisting of sixteen turns of 12 AWG wire, spaced 0.5 inch between
adjacent turns, for a total height (length) of eight inches. The coil is
centered on the length of the monopole and the monopole is brought to
resonance by using the resonating function of MultiNEC to adjust the
radius of the coil. Eight, single segment wires arranged in octagonal
form approximate each turn of the circular coil, for a total of 128
single-segment wires."

Exactly what did I miss?
--
73, Cecil http://www.w5dxp.com

Phase Shift through a 75m Texas Bugcatcher Coil
 

Cecil Moore wrote:
...
Standing wave current cannot be used to make valid
measurements about current amplitude "drops" across
or phase shifts through a loading coil. One must
instead figure out a way to get a traveling wave
flowing through the coil. Then the phase shift
becomes perfectly obvious.
...

So, "something" roughly related to [speed-of-light -
velocity-factor-of-conductor = phase-shift] should be at play (since
photons are speed of light and the rf wave is limited by the VF) ???

Regards,
JS

Phase Shift through a 75m Texas Bugcatcher Coil
 

John Smith I wrote:
So, "something" roughly related to [speed-of-light -
velocity-factor-of-conductor = phase-shift] should be at play (since
photons are speed of light and the rf wave is limited by the VF) ???

Coherent EM waves traveling in opposite directions can
certainly confuse the observer. In order to remain un-
confused, one EM wave traveling in one direction should
be the wave used for measurements. Otherwise intelligent
people have been completely fooled by the two waves traveling
in opposite directions. The resultant wave is an illusion
and therefore the observations based on standing waves are
likewise illusions.

How can a standing wave, whose amplitude is dependent
upon the the phases of the two traveling waves, be
used to determine anything about amplitude? How can
the phase, which is essentially fixed and constant
at zero degrees, be used to determine phase delay?

Standing waves have faked the gurus out of their
jockey straps.
--
73, Cecil http://www.w5dxp.com

Phase Shift through a 75m Texas Bugcatcher Coil
 

Cecil Moore wrote:
...
How can a standing wave, whose amplitude is dependent
upon the the phases of the two traveling waves, be
used to determine anything about amplitude? How can
the phase, which is essentially fixed and constant
at zero degrees, be used to determine phase delay?

Standing waves have faked the gurus out of their
jockey straps.


Cecil:

Just using logic, an "interference wave" (standing wave) would seem to
be a poor choice, alright.

But then, my knowledge on this subject makes me dependent upon others, I
am listening and attempting to get a grasp on things ... sorry if my
ignorance can be taxing at times ... frankly, even to attempt to discern
between forward-reflected-standing for the purposes you propose has
never entered my mind!

Give me a bit, as with others here, this all is taking a bit of time to
get ones' mind wrapped around. You have given this quite a bit of
thought, I am just beginning down that path ... perhaps when I learn
enough, I will agree or disagree.

However, you have already given me a bit to play with, such as
attempting to "repel photons" from transversing windings. LOL!

Regards,
JS

Phase Shift through a 75m Texas Bugcatcher Coil
 

John Smith I wrote:
...
However, you have already given me a bit to play with, such as
attempting to "repel photons" from transversing windings. LOL!
...

Geesh, everyone must be slow today, sure I would get jumped about using
transversing instead of the proper use of traversing ...

JS

Phase Shift through a 75m Texas Bugcatcher Coil
 

On Sun, 13 May 2007 18:17:29 GMT, Cecil Moore
wrote:

Tedious Xerography snipped as being obviously unread by Xerographer.

Exactly what did I miss?

If you have to be taken by the hand to have it pointed out to you, you
shouldn't be doing these kind of things without adult supervision.

A
I have taken Wes's helical coil from:
http://www.k6mhe.com/n7ws/Loaded%20antennas.htm
B
and modeled it with EZNEC. ...
That coil512.EZ file can be downloaded from:

is distinctly false.

A B
Does a symbolic reply nail it down?

Phase Shift through a 75m Texas Bugcatcher Coil
 

On May 12, 7:10 am, "Yuri Blanarovich" wrote:


When Barry, W9UCW did his experiments and measurements, he was surprised
that quality of the loading coil made hardly any difference. Like good
Bugcatcher coil vs. bad Hustler type resonator.

Dunno, I don't see too much difference between any of my homebrew
coils, but when I compared any of those to a hustler, there was a
large
noticable difference. The hustler was terrible.. Like a dummy load on
a
stick. But in comparing any of my usual coils, I don't see a large
difference
in any of them, including those with heavy gauge wire, vs those with
thinner gauge wire.
I've found thinner gauge wire is just fine as long as the wires are
not wound
too close together.
If one tried a hustler coil, and a good bugcatcher coil, and saw
little or
no difference, I would think ground loss was severely overshadowing
coil
loss.
The less ground loss, the more apparant will coil loss become.
Of course, the large hustler coils have a fairly well known design
defect,
and I consider them defective units vs a usual mobile loading coil.
Even my cheap homebrew coils are far superior, and I do nothing
special..
I once did a side by side test of my mobile vs a friends using a
hustler
mast and resonator on 75m. No contest.. He was in the noise to many
stations, where I was solid copy to most all.. About a 2 S unit ?
difference
on average.

Do we have the case where some power is being lost for the benefit of
stretching the high current portion along the radiator and making up for
losses?

Sorta.. To an extent anyway...
The peak point being probably around 75% or so of the total height..
Get too carried away, and excess coil loss will start to offset gains
in efficiency from the improved current distribution.
In testing all my coils, antennas, etc, I've found Reg's program
"vertload"
to be fairly accurate. Both in general performance estimates, but also
in the estimates on coil loss vs size of wire, etc.. His program said
thinner
wire should be ok with only slight losses vs thicker wire, with a
proper pitch
and wire spacing, and in real life it seemed to pan out pretty close.
A center load coil, with more turns than a base load, will have more
loss.
But the overall antenna efficiency is greatly improved, so I know
which
line I'll be standing in when I pick which one I want to use. :/
If you use a large enough top hat, you can have a base loading coil,
and
still have good current distribution. But I don't use hats on
mobiles..
#1, pretty freaking ugly.. #2, I'll kill them on tree branches fairly
quick..
#3, too much wind load at highway speeds.. Tend to flop and whip about
with my flexible fibreglass "masts"..
I use a center loading coil and a fairly long whip as a decent
compromise.
In the driving mode, I have 5 ft under the coil, and 5 ft above it..
In the parked mode, I have 8 ft under the coil, and 5 ft over it by
adding an
extra 3 ft hustler mast at the base.
If thats on one of my trucks, my coil is higher than many peoples
total
antenna height.. :) At this date, I'm still too chicken to drill a
hole in my
latest car, which is a 2005 corolla... The bad part is thats the one
I
drive most of the time lately...
My honda accord is radioactive, as are both of my trucks, but the
trucks
burn too much gas, and the accord needs some work.. It doesn't get as
good a mpg as the corolla either, although both weigh about the same.
I'm lucky to get 30 on the road in the accord, where the corolla gets
about 37-40 depending on speed..
But I miss not having a radio on the road at night... I've already
been to
my lake property up in OK. four times in that car since I got it..
"905 mile round trip" I've put about 8k on that car already, and have
had
it maybe 3 months or so...
The last was a couple of weeks ago. I did install a 80 and 40 single
coax fed
dipole rig up there last time, so at least the property is radioactive
even if my
car isn't.. That helps...
I strung it up in an old oak tree, and left the coax rolled up by the
tree.
When I pull up, the coax is long enough to reach about anywhere I'd
have
the radio, including in the car. I'll probably add 160m legs later..
MK

Phase Shift through a 75m Texas Bugcatcher Coil
 

I wrote:
"Current does not jump off the rails in a coil, it follows the coil wire
as it follows a straight wire elsewhere."

Wikipedia says, electrical conduction is the movement of charged
particles through an electrical conductor. The movement forms an
electrical current in response to an electric field.

Inductance is passive and though it opposes a change in current, nowhere
is the inducement to conduct any stronger than it is where the source
connects with the coil. The charges at the ends of a coil are going to
press on their neighbors to move on and keep the conduction going.

Inductance results from the magnetic field that forms around a current
carrying conductor. Electrical current through the conductor creates a
magnetic flux proportional to the current.

When there is an AC sinusoidal source, the phase of the current through
a pure inductance lags the voltage by 90 degrees.

Best regards, Richard Harrison, KB5WZI

Phase Shift through a 75m Texas Bugcatcher Coil
 

FYI -

Reg Edwards' program produces a VF of .0333 and a delay of 26 degrees
for the 75m Bugcatcher coil.

ac6xg

Cecil Moore wrote:

The following web page is representative of the side that
asserts there is virtually zero delay through a 75m loading
coil. But the backers of that argument have grown strangely
silent as of late.

http://www.w8ji.com/inductor_current_time_delay.htm

Phase Shift through a 75m Texas Bugcatcher Coil
 

Jim Kelley wrote:
Reg Edwards' program produces a VF of .0333 and a delay of 26 degrees
for the 75m Bugcatcher coil.

Thanks Jim,

Dr. Corum's formula indicates a VF of ~0.02

EZNEC indicates a VF of ~0.016

The "threaded bolt" method indicates a VF of ~0.006

w8ji indicates a VF of ~0.42 for his 100 turn,
10 inch long, 2 inch diameter coil.

In order to get a valid measurement of the delay
through a coil, the coil needs to be loaded with
its characteristic impedance to minimize the
reflected current. With mostly traveling wave
current flowing through the coil, the delay is easy
to measure.
--
73, Cecil http://www.w5dxp.com