Phase Shift through a 75m Texas Bugcatcher Coil
 

Cecil Moore wrote:
Jim Kelley wrote:
But you aren't measuring it. The point is, it's calculable.

But w8ji and w7el *are* measuring it and getting something
different from those calculations. They are reporting their
flawed measurements as technical fact. That's what the
whole argument is about.

Only because you keep dragging them into it. I'm perfectly happy just
comparing your results with the results I get from Reg's program.

There is no way in heck to get a
3 nS delay out of a 100 turn, 10", 2" diameter coil.

There is something odd about Tom's printout. It's not clear to me
exactly what the instrument is actually displaying.

The fact that it doesn't give you an answer that agrees with any other
method notwithstanding.


It means that the existing posted methods are invalid.

:-) There exists no other possibility, naturally. I believe they call
these delusions of grandeur.

If I were trying to measure delay I would use pulses.


How do you know the pulsed delay is the same as the
steady-state delay?

In the same way, and to the same degree that I know the delay will be
the same tomorrow as it is today.

Has anyone published a delay using
pulses?

Delays are typically measured using pulses.

If it is a DC pulse, there
would be known problems.

Oh, I would never use those. :-)

I would want the system to be configured in exactly the same way as I
intended for it to be used.


Then you will find it is impossible to measure the delay
through the coil during steady-state.

If I thought that was true, I wouldn't have said what I did.

ac6xg

Phase Shift through a 75m Texas Bugcatcher Coil
 

Cecil, W5DXP wrote:
"EZNEC indicates a VF of ~ 0.016."

I calculate about 628 inches of wire in the coil compared with about 10
inches of coil length. It is 62.8 times as far to go around the turns on
the coil as it is to travel through a 10 inch rod. So, velocity factor
is the quotient of 10 divided by 628, or about 0.016. That agrees with
EZNEC.

Best regards, Richard Harrison, KB5WZI

Phase Shift through a 75m Texas Bugcatcher Coil
 

Cecil, W5DXP wrote:
"There is no way in heck to get 3 nanoseconds delay out of a 100 turn,
10-in., 2-in dia. coil."

I calculate 628 in. of wire divided by c (@ 1181.1x10 to the sixth power
in./sec.) = 0.53x10 to the minus 6 power, delay through the coil. That`s
just over 1/2 microsecond delay in the coil. A lot slower than Tom`s
coil but my signal sticks to the wire.

Best regards, Richard Harrison, KB5WZI

Phase Shift through a 75m Texas Bugcatcher Coil
 

dos'nt make much difference? then none of this has any point then?

On May 15, 10:32 am, Cecil Moore wrote:
wrote:
Cecil doesnt seem to worry about this error, but just saying it
doesn't actually mean anything without differences.

Don, I worry about any error but I don't know
what the error is and Richard C. won't tell me.
But that's just his style. Upon closer reading,
Wes's coil is closer to 7 inch diameter but
that doesn't make much difference.
--
73, Cecil http://www.w5dxp.com

Phase Shift through a 75m Texas Bugcatcher Coil
 

I still dont see differences
just saying it doesmn't make it so. Does it?

ok different coil size, but no one seems to be able to say what this
abour (sure delay, all coils have delay and none nows how much except
that it isnt much different from another coil).

coke = pepsi woohoo!

On May 15, 11:40 am, Richard Clark wrote:
On 15 May 2007 10:27:19 -0700, wrote:

Cecil doesnt seem to worry about this error, but just saying it
doesn't actually mean anything without differences. What is different
about his claim and Wests'?

Hi Herbert,

Yeah, I've noticed he's sloughed off your tough questions. The
differences are in the claim of having modeled Wes' helix, he did not,
it is a helix of Cecil's own invention. This is the problem of
leverage sources' credibility: use their name and discard their work
where it conflicts with your own. The differences (as I understand
your desire for actual data content) consist in the wrong pitch and
the wrong diameter. Aside from that, they are identical.

Now, how far can Cecil take a proof using this identity? All the way
within ±CSE (Cecil Standard Error, which as a numeric is 67%). The
world of theory is wide open when you cut yourself that much slack.

73's
Richard Clark, KB7QHC

Phase Shift through a 75m Texas Bugcatcher Coil
 

wrote:

dos'nt make much difference? then none of this has any point then?


You've begun to get it.

tom
K0TAR

On May 15, 10:32 am, Cecil Moore wrote:

wrote:

Cecil doesnt seem to worry about this error, but just saying it
doesn't actually mean anything without differences.

Don, I worry about any error but I don't know
what the error is and Richard C. won't tell me.
But that's just his style. Upon closer reading,
Wes's coil is closer to 7 inch diameter but
that doesn't make much difference.
--
73, Cecil http://www.w5dxp.com

Phase Shift through a 75m Texas Bugcatcher Coil
 

herbert.don wrote:
"coke = pepsi woohoo!"

A loading coil is important to tune out the capacitive reactance of a
too-short whip so that maximum current can be put into the antenna to
get the most RF radiation out.

A loading coil usually has some loss that takes the form of heat
converted from some of the energy pumped into it.

One of the debates here may have been triggered by reference to John
Devoldere, ON4UN`s treatment of "short verticals" in "Low-Band DXing".
He discussed several ways to resonate the too-short vertical antenna.
His Fig. 9-22 on page 9-15 of his 1994 edition became notorious.

ON4UN occasionly characterizes coils as having "degrees" in the space
occupied in the antenna. No one argues that a 1/4-wave vertical does not
have 90 degrees, or that at a given frequency, you could not properly
say a certain linear measure was not equal to a degree. So, if you are
trying to resonate the antenna as a 1/4-wavelength, why not assign the
missing length of antenna, in degrees, to the coil or coils which
replace the missing length of antenna?

The number of turns required of the coil or coils depends on where it or
they are placed in the antenna. A certain number of turns are not
predetermined to represent so many degrees independent of placement.

More than just resonating the antenna, placement of the coil or coils
affects current distribution which affects radiation and loss. Several
problems need simultaneous solution to get the best performance.

I have mostly thought of the velocity of light as being a universal
speed limit. I read long ago that energy is transferred by passing an
impetus along a group of extremely short gap distances through a file of
charges. The individual charges are migrating slowly, if at all, and
going nowhere fast. Speeds greater than the speed of light seemed
inconceivable to me. Researching the loading coil brought me to Kraus
and his helical antenna. On page 253 of the 3rd edition of "Antennas" is
Figure 8-32. For certain coils it shows velocities exceeding the speed
of light. I guess I`m not too old to learn after all.

Best regards, Richard Harrison, KB5WZI

Phase Shift through a 75m Texas Bugcatcher Coil
 

On Tue, 15 May 2007 22:02:56 -0500, (Richard
Harrison) wrote:

On page 253 of the 3rd edition of "Antennas" is
Figure 8-32. For certain coils it shows velocities exceeding the speed
of light.

Hi Richard,

The velocities of what?

73's
Richard Clark, KB7QHC

Phase Shift through a 75m Texas Bugcatcher Coil
 

"Cecil Moore" wrote in message
...
If a Texas Bugcatcher Coil could be turned into a
traveling wave device instead of a standing wave
device, the inherent phase shift through the coil
would become obvious. I used the Helix option in
EZNEC to generate a reasonably close model of a
75m Texas Bugcatcher coil and loaded it with a
resistance equal to the coil's characteristic impedance
which essentially eliminated the reflected current,
leaving the forward current intact and visible. All
of the data points on the following web page came from
EZNEC. All of the files are available for downloading.
Please take a look at:

http://www.w5dxp.com/current2.htm
--
73, Cecil http://www.w5dxp.com

Phase Shift through a 75m Texas Bugcatcher Coil
 

Richard Clark, KB7QHC wrote:
"The velocities of what?"

Figure 8-32 labels the ordinate values as "relative phase velocity".
Phase velocity is defined in my electronic dictionary as:
"The velocity at which a point of constant phase is propagated in a
progressive sinusoidal wave."

In other words, pick a point on a waveform. The rate at which it moves
is phase velocity. That`s the velocity of propagation.

Best regards, Richard Harrison, KB5WZI