Cecil Moore wrote:

SNIPPED

Quoting from the Corum paper concerning self resonance
of a coil:

"The forward and backward traveling waves have superposed
to give this voltage standing wave distribution along the
resonator. There is a voltage null at the base, a voltage
maximum at the top, and a sine wave envelope along the
structure." That defines 90 degrees of coil.

For the standing wave, there are 90 degrees between a voltage
null and a voltage maximum. The voltage maximum at the top
of the coil corresponds to the current null existing there
because the current has no place to go. The voltage null at
the base corresponds to the current maximum there which is
a necessary condition for self resonance. There's 90 degrees
between a voltage null and a voltage maximum. There's 90
degrees between a current null and a current maximum.

Under that definition my 8 foot high mobile antenna has a voltage
maximum at the top and a current maximum at the base and must,
therefore, be 90 degrees long. But, it is physically only 16 degrees
long [8/43.5 @ 5.37 MHz]. Now it is 5 degrees long above the top of the
coil and 10 degrees long below the coil ... ad nauseum [ for another 2
months ] ...

Where is the other 74 degrees?? This is the question that started this
2 month discussion.

Is there a fallacy in Corum's paper?

Does Corum's paper apply to a combination of a loading coil and
radiating elements?

My reasoning is as follows: if I draw a phasor diagram, I have +10
degrees phase shift from the feed point to the base of the coil. I can
then assume a +90 degree phase shift in the coil, classical inductive
response; then, the 'stinger', from the top of the coil to the tip of
the antenna produces a net -10 degree phase shift from both inductive[+]
and capacitive[-] effects resulting in a net 90 degree phase shift for
the full eight foot antenna.

Am I being too simplistic?

I conclude that I have a 16 degree long antenna with a feedpoint
resistance of ~13 ohms [ Rr = ~1.0 ohm and Rloss = ~12 ohms] with zero
ohms reactance [resonant]. [And that the phase shifts stated above are
fundamentally correct.]

Dave wrote:
Where is the other 74 degrees??

Please reference my other postings. It is all explained
there.

1. There are tens of degrees in the coil. That phase shift
is not instantaneous and obeys the VF of the coil.

2. There are tens of degrees in the impedance discontinuity
between the coil and stinger. That phase shift is instantaneous
and requires no delay.

3. There are tens of degrees in the stinger. That phase shift
is not instantaneous and obeys the VF of the stinger.

4. They all add up to 90 degrees.
--
73, Cecil http://www.qsl.net/w5dxp

Dave wrote:

Where is the other 74 degrees?? This is the question that started this
2 month discussion.

Is there a fallacy in Corum's paper?

Does Corum's paper apply to a combination of a loading coil and
radiating elements?

My reasoning is as follows: if I draw a phasor diagram, I have +10
degrees phase shift from the feed point to the base of the coil. I can
then assume a +90 degree phase shift in the coil, classical inductive
response; then, the 'stinger', from the top of the coil to the tip of
the antenna produces a net -10 degree phase shift from both inductive[+]
and capacitive[-] effects resulting in a net 90 degree phase shift for
the full eight foot antenna.

Am I being too simplistic?

I conclude that I have a 16 degree long antenna with a feedpoint
resistance of ~13 ohms [ Rr = ~1.0 ohm and Rloss = ~12 ohms] with zero
ohms reactance [resonant]. [And that the phase shifts stated above are
fundamentally correct.]

You don't need to go to anywhere near that much trouble. If you replace
the stinger with a lumped series RC to ground with the same impedance as
the stinger, you'll get nearly the same currents, both magnitude and
phase, at the top and bottom of the coil as you did with the stinger. No
"missing degrees" -- no "degrees" at all, in fact. No forward and
reverse traveling waves, no standing waves. No smoke and mirrors, no
bafflegab. Just plain old circuit analysis.

Roy Lewallen, W7EL

Roy Lewallen wrote:
You don't need to go to anywhere near that much trouble. If you replace
the stinger with a lumped series RC to ground with the same impedance as
the stinger, you'll get nearly the same currents, both magnitude and
phase, at the top and bottom of the coil as you did with the stinger. No
"missing degrees" -- no "degrees" at all, in fact. No forward and
reverse traveling waves, no standing waves.

No understanding of the laws of physics -
just 1001 shortcuts and rules of thumb -
consistent with the dumbing down of the
US educational system and amateur radio.
--
73, Cecil http://www.qsl.net/w5dxp

"Dave" wrote in message
. ..

Under that definition my 8 foot high mobile antenna has a voltage maximum
at the top and a current maximum at the base and must, therefore, be 90
degrees long. But, it is physically only 16 degrees long [8/43.5 @ 5.37
MHz]. Now it is 5 degrees long above the top of the coil and 10 degrees
long below the coil ... ad nauseum [ for another 2 months ] ...

Where is the other 74 degrees?? This is the question that started this 2
month discussion.


Dave,
your 8 ft mobile antenna is not 90 degrees long, you don't have zero
reactance at the feedpoint. You will have to insert the loading coil or
matching network to do that and that adds the missing degrees. (You might
have maximum current as far as the whip is concerned, but not maximum
current corresponding to the base of resonated whip, just fraction
corresponding what standing wave would supply for that tip o'antenna.)
Then you have drop of current along the coil, (missing degrees) and rest in
the stinger at corresponding degreed to the straight radiator. (Worst
efficiency of that length of antenna.).
As you start moving the loading coil up the antenna, you start increasing
the high current in bottom part of antenna, then drop along the coil, then
rest of the drop towards the stinger, down to zero. As you move coil higher,
you will have to add the turns in order to maintain resonance (90 degrees
overall, zero reactance at the feedpoint).
Looks like my idea about the role of impedance has some merit, Cecil is
hitting it with idea of "losing" some degrees at the impedance "bumps"
completing the picture of them mysteriously missing degrees, to dismay of
same current believers. So looks like degrees of mast, plus degrees of
impedance bump between the mast and coil, plus degrees of coil, plus degrees
of impedance bump between the coil and stinger, plus degrees of stinger
should add up to 90 degrees in resonant monopole or resonator, as some
antenna pioneers called it. Do we get it now more precisely? Or there are
still some "missing" degrees floating around?

73 Yuri, K3BU/m