A long time ago there was a arguement both on this group and on E ham
with respect to the function of a coil with respect to replacing
missing degrees of a wavelength.
Both Tom W8ji and Roy W7EL did experiments which apparently justified
an account written up by Tom under the subject.
You should look it up and read it.
Tom states that the double helix is totally resistive and antenna
elements should be straight reffering to spacial distance.,
He then came to the astonishing conclusion that for maximum efficiency
radiators should be straight and for some reason dismissed the double
helix to give strength to his claim that radiators must be straight
which is fraudulent. A straight radiator generates a external magnetic
field which introduces losses whereas the double helix supplies all
applied current to the generation of radiation. None of the experts on
either group challenged challenged the statement allegedly supported
by both Tom and Roy
and it still remains in print to this day
Art

On Aug 28, 9:23*pm, Art Unwin wrote:
A long time ago there was a arguement both on this group and on E ham
with respect to the function of a coil with respect to replacing
missing degrees of a wavelength.
Both Tom W8ji and Roy W7EL did experiments which apparently justified
an account written up by Tom under the subject.
You should look it up and read it.
Tom states that the double helix is totally resistive and antenna
elements should be straight reffering to spacial distance.,
He then came to the astonishing conclusion that for maximum efficiency
radiators should be straight and for some reason dismissed the double
helix to give strength to his claim that radiators must be straight
which is fraudulent. A straight radiator generates a external magnetic
field which introduces losses whereas the double helix supplies all
applied current to the generation of radiation. None of the experts on
either group challenged challenged the statement allegedly supported
by both Tom and Roy
and it still remains in print to this day
Art

I continued on reading Toms many dissertations on radiation and
antennas when I came across a lecture he gave at Dayton regarding
small antennas. Again he pushed his personal intuition with respect to
small antennas and spacial distance
and received no rebuttals from the audience or the ARRL . In addition
he always spouts his pet sentence on radiation is by the acceleration
of charge but never states what the charge carrier is
as he is still wedded to the idea of wave carriers which has no
justification what so ever. We desperately need the help from physics
majors to challenge the spread of old wives tales that are propagated
without technical justification and sucked in by the new generation of
which the hobby is now created or we lose the credibility obtained by
hams who foraged before us with respect to the state of the art.
Art Unwin

On 8/28/2010 10:28 PM, Art Unwin wrote:
On Aug 28, 9:23 pm, Art wrote:
A long time ago there was a arguement both on this group and on E ham
with respect to the function of a coil with respect to replacing
missing degrees of a wavelength.
Both Tom W8ji and Roy W7EL did experiments which apparently justified
an account written up by Tom under the subject.
You should look it up and read it.
Tom states that the double helix is totally resistive and antenna
elements should be straight reffering to spacial distance.,
He then came to the astonishing conclusion that for maximum efficiency
radiators should be straight and for some reason dismissed the double
helix to give strength to his claim that radiators must be straight
which is fraudulent. A straight radiator generates a external magnetic
field which introduces losses whereas the double helix supplies all
applied current to the generation of radiation. None of the experts on
either group challenged challenged the statement allegedly supported
by both Tom and Roy
and it still remains in print to this day
Art

I continued on reading Toms many dissertations on radiation and
antennas when I came across a lecture he gave at Dayton regarding
small antennas. Again he pushed his personal intuition with respect to
small antennas and spacial distance
and received no rebuttals from the audience or the ARRL . In addition
he always spouts his pet sentence on radiation is by the acceleration
of charge but never states what the charge carrier is
as he is still wedded to the idea of wave carriers which has no
justification what so ever. We desperately need the help from physics
majors to challenge the spread of old wives tales that are propagated
without technical justification and sucked in by the new generation of
which the hobby is now created or we lose the credibility obtained by
hams who foraged before us with respect to the state of the art.
Art Unwin

Thanks for those. I needed a good laugh.

tom
K0TAR

On Aug 29, 2:23*am, Art Unwin wrote:
A long time ago there was a arguement both on this group and on E ham
with respect to the function of a coil with respect to replacing
missing degrees of a wavelength.
Both Tom W8ji and Roy W7EL did experiments which apparently justified
an account written up by Tom under the subject.
You should look it up and read it.
Tom states that the double helix is totally resistive and antenna
elements should be straight reffering to spacial distance.,
He then came to the astonishing conclusion that for maximum efficiency
radiators should be straight and for some reason dismissed the double
helix to give strength to his claim that radiators must be straight
which is fraudulent. A straight radiator generates a external magnetic
field which introduces losses whereas the double helix supplies all
applied current to the generation of radiation. None of the experts on
either group challenged challenged the statement allegedly supported
by both Tom and Roy
and it still remains in print to this day
Art

so? many incorrect things are in print, do you believe all of them?
i think your double helixes are missing a few turns here and there.

On Aug 29, 3:28*am, Art Unwin wrote:
On Aug 28, 9:23*pm, Art Unwin wrote:



A long time ago there was a arguement both on this group and on E ham
with respect to the function of a coil with respect to replacing
missing degrees of a wavelength.
Both Tom W8ji and Roy W7EL did experiments which apparently justified
an account written up by Tom under the subject.
You should look it up and read it.
Tom states that the double helix is totally resistive and antenna
elements should be straight reffering to spacial distance.,
He then came to the astonishing conclusion that for maximum efficiency
radiators should be straight and for some reason dismissed the double
helix to give strength to his claim that radiators must be straight
which is fraudulent. A straight radiator generates a external magnetic
field which introduces losses whereas the double helix supplies all
applied current to the generation of radiation. None of the experts on
either group challenged challenged the statement allegedly supported
by both Tom and Roy
and it still remains in print to this day
Art

I continued on reading Toms many dissertations on radiation and
antennas when I came across a lecture he gave at Dayton regarding
small antennas. Again he pushed his personal intuition with respect to
small antennas and spacial distance
and received no rebuttals from the audience or the ARRL . In addition
he always spouts his pet sentence on radiation is by the acceleration
of charge but never states what the charge carrier is
as he is still wedded to the idea of wave carriers which has no
justification what so ever. We desperately need the help from physics
majors to challenge the spread of old wives tales that are propagated
without technical justification and sucked in by the new generation of
which the hobby is now created or we lose the credibility obtained by
hams who foraged before us with respect to the state of the art.
Art Unwin

its all up to you art, i suggest you write the definitive expose on
antenna myths... it should find a good spot in the humor section of
the book stores.

On Aug 28, 9:23*pm, Art Unwin wrote:
A long time ago there was a arguement both on this group and on E ham
with respect to the function of a coil with respect to replacing
missing degrees of a wavelength.
Both Tom W8ji and Roy W7EL did experiments which apparently justified
an account written up by Tom under the subject.

I am completely ignorant of your "double helix" so I cannot comment on
that subject. I always thought a double helix was a strand of DNA.

On the subject of the number of degrees occupied by a loading coil,
both Tom and Roy made an incorrect assumption that rendered their
conclusions at best moot, and at worst false. Roy reported no
measurable phase shift in the current through a loading coil and
seemed to support the misconception that the phase shift is
proportional to the delay through the coil, which it is not.

Both Tom and Roy seemed to assume that the antenna current changes
phase by one electrical degree for each physical degree of antenna.
But EZNEC easily proves that to be an incorrect assumption for the
current in a standing-wave antenna which includes dipoles, monopoles,
and loaded mobile antennas. The following applies to 1/2WL dipoles and
1/4WL monopoles including loaded mobile antennas.

THE PHASE OF THE NET CURRENT IN A STANDING-WAVE ANTENNA CHANGES VERY
LITTLE BETWEEN THE FEEDPOINT AND THE TIP END OF THE ANTENNA.

*The phase of that current cannot be used to calculate the delay
through a wire or through a loading coil.* The phase of the net
current in a thin-wire 1/4WL monopole changes by ~3 degrees over a 90
degree physical length. The same is true for a loaded mobile antenna.
Anyone assuming that signal delay is proportional to current phase
shift in a standing wave antenna is off by a magnitude or more. Tom's
reported 3 ns delay through his coil is about 12% of the actual value
of the delay at 4MHz.

The following inductance calculator can be used to estimate the delay
through a loading coil. The parameter to use is the "Beta = rad/m,
Axial propagation factor of n=0 sheath helix waveguide mode at design
frequency[1,8]'

http://hamwaves.com/antennas/inductance.html

The rad/m of the axial propagation factor can be used to calculate the
number of degrees occupied by the specified loading coil and the
velocity factor of the loading coil. The 100T, 10" coil that Tom used
for his "measurements" has a delay of ~30 degrees at 4 MHz, virtually
unrelated to the phase-shift in the standing-wave current that he
reported. Delay is NOT proportional to current phase-shift on a
standing-wave antenna and certainly not for the loading coils on a
standing wave antenna. However, delay is proportional to current phase-
shift on a traveling-wave antenna.
--
73, Cecil, w5dxp.com

On Aug 29, 4:45*pm, Cecil Moore wrote:
On Aug 28, 9:23*pm, Art Unwin wrote:

A long time ago there was a arguement both on this group and on E ham
with respect to the function of a coil with respect to replacing
missing degrees of a wavelength.
Both Tom W8ji and Roy W7EL did experiments which apparently justified
an account written up by Tom under the subject.

I am completely ignorant of your "double helix" so I cannot comment on
that subject. I always thought a double helix was a strand of DNA.

On the subject of the number of degrees occupied by a loading coil,
both Tom and Roy made an incorrect assumption that rendered their
conclusions at best moot, and at worst false. Roy reported no
measurable phase shift in the current through a loading coil and
seemed to support the misconception that the phase shift is
proportional to the delay through the coil, which it is not.

Both Tom and Roy seemed to assume that the antenna current changes
phase by one electrical degree for each physical degree of antenna.
But EZNEC easily proves that to be an incorrect assumption for the
current in a standing-wave antenna which includes dipoles, monopoles,
and loaded mobile antennas. The following applies to 1/2WL dipoles and
1/4WL monopoles including loaded mobile antennas.

THE PHASE OF THE NET CURRENT IN A STANDING-WAVE ANTENNA CHANGES VERY
LITTLE BETWEEN THE FEEDPOINT AND THE TIP END OF THE ANTENNA.

*The phase of that current cannot be used to calculate the delay
through a wire or through a loading coil.* The phase of the net
current in a thin-wire 1/4WL monopole changes by ~3 degrees over a 90
degree physical length. The same is true for a loaded mobile antenna.
Anyone assuming that signal delay is proportional to current phase
shift in a standing wave antenna is off by a magnitude or more. Tom's
reported 3 ns delay through his coil is about 12% of the actual value
of the delay at 4MHz.

The following inductance calculator can be used to estimate the delay
through a loading coil. The parameter to use is the "Beta = rad/m,
Axial propagation factor of n=0 sheath helix waveguide mode at design
frequency[1,8]'

http://hamwaves.com/antennas/inductance.html

The rad/m of the axial propagation factor can be used to calculate the
number of degrees occupied by the specified loading coil and the
velocity factor of the loading coil. The 100T, 10" coil that Tom used
for his "measurements" has a delay of ~30 degrees at 4 MHz, virtually
unrelated to the phase-shift in the standing-wave current that he
reported. Delay is NOT proportional to current phase-shift on a
standing-wave antenna and certainly not for the loading coils on a
standing wave antenna. However, delay is proportional to current phase-
shift on a traveling-wave antenna.
--
73, Cecil, w5dxp.com

but of course we all know that a standing wave is a figment of your
instrumentation!

On Aug 28, 9:23*pm, Art Unwin wrote:
A long time ago there was a arguement both on this group and on
E ham with respect to the function of a coil with respect to replacing
missing degrees of a wavelength.

The purpose and function of a loading coil used with an electrically
short antenna is to offset the capacitive reactance of the short
radiating section. Otherwise it will not accept much power from a
transmitter or deliver much power to a receiver, due to a very high
mismatch to common types of transmission line connected to its
terminals.

Check this using a simple NEC model. The model will have ~ the same
radiation resistance, radiation pattern, and gain in dBi whether or
not a loading coil at the feedpoint makes the antenna system resonant,
other things equal.

J. Kraus states in the link below that the radiation resistance of a
loaded vertical (for instance) is nearly the same as that of an
unloaded vertical of the same height.

That a loading coil contributes "missing degrees" to resonate a short
antenna is rather a specious concept.

http://i62.photobucket.com/albums/h8...ndVertical.gif

RF

On 8/29/2010 9:45 AM, Cecil Moore wrote:


I am completely ignorant of your "double helix" so I cannot comment on
that subject. I always thought a double helix was a strand of DNA.


73, Cecil, w5dxp.com

On the helix coil, of any helical wound loading coil, or even a linear
loaded monopole/dipole, you can wind another helix, in between the turns
of the first helix, both ends are open and not connected. This tends to
expand the antennas' bandwidth, "normalize" ant impedance, etc.

That is the only thing I can figure he is referring to ...

Regards,
JS

On 8/28/2010 7:23 PM, Art Unwin wrote:
...
Art

Having locked myself away for months, wife will claim years, and
searching for the "best" shortened stealth antenna(s), I have been
forced to employ coils. In any loaded antenna (hide the JD!) the coil
is best at the bottom with a .62 L/D ratio. I currently use DLM's from
Robert Vincents' patent, it allows me to break the laws ... others
research and mileage may vary.

The loading coil adds +J to compensate the -J from a short antenna ...
however, old hams taught me that the coil adds electrical degrees, God
bless them ...

Regards,
JS