I understand that E and H fields are intrinsic parts of the same thing (for
radio waves, etc), and I am not trying to separate them along the lines
discussed by some list participants.

I would think that the E and H ratio of 377 is a function of the SI units of
measurement involved. It would seem that there is the same amount of energy
(at different and selected instances) in the E and H waves, and different
units of measurement could produce a ratio of 1:1 (or anything else, with
appropriate units of measurement).

To return to the ferrite rod antenna: Ignoring the directional null
capability (which might be very useful in some real-world circumstances) is
there any advantage to a small ferrite rod antenna over a short wire antenna
(assuming perfect amplifiers, as needed, following the antennas and assuming
160m or 80m usage)?

As mentioned earlier, there have been a number of construction articles over
the years explaining how a ferrite rod antenna did wonderful things for
160/80 operation. I have wondered if these results are generally valid, or
were the result of the authors' pride in their works, or happened because
the directional null abilities solved a local problem.

Bill - W2WO

My reality, and Tom's, fits with the clear explanations in Johnson's
_Antenna Engineering Handbook_ (successor to Jasik); King and Harrison's
_Antennas and Waves_; King, Mimno, and Wing's _Transmission Lines,
Antennas, and Wave Guides_; and undoubtedly others, since it comes from
basic electromagnetic principles.

I explained the nature of the E and H fields from a small loop antenna.
This is the sum of the fields from each part of the loop. It is not
representative of the field in the small region between the wire and
shield of a "shielded" loop, as you seem to be trying to infer.

If you'd spend a fraction of the time studying that you spend
desperately trying to find something wrong with anything Tom says, you'd
have a much better understanding of how antennas work.

Roy Lewallen, W7EL

Yuri Blanarovich wrote:
"Roy Lewallen" wrote in message
...
Yuri Blanarovich wrote:
. . .
Roy, 'splain to him about this 1/8 or so thing. He still dungetit.
Tom understands it, but I see you don't quite have a handle on it yet.

Roy Lewallen, W7EL

So I "don't get it" because I (and others) see the difference in reality,
when electrostatic shield suppresses the local interference. You explain
behavior of E and H field in the vicinity of antenna but that does not apply
to "W8JI shield is the antenna" and "current at both ends of the loading
coil is always the same".

I will stick to my reality handle, rather than joining scientwist's chorus.

73 Yuri, K3BU

Bill Ogden wrote:
I understand that E and H fields are intrinsic parts of the same thing (for
radio waves, etc), and I am not trying to separate them along the lines
discussed by some list participants.

I would think that the E and H ratio of 377 is a function of the SI units of
measurement involved. It would seem that there is the same amount of energy
(at different and selected instances) in the E and H waves, and different
units of measurement could produce a ratio of 1:1 (or anything else, with
appropriate units of measurement).

Yes, that's correct. What I tried to do in my explanation was to relate
the E/H ratio near a small loop with that of free space. That makes the
units of measure immaterial.

To return to the ferrite rod antenna: Ignoring the directional null
capability (which might be very useful in some real-world circumstances) is
there any advantage to a small ferrite rod antenna over a short wire antenna
(assuming perfect amplifiers, as needed, following the antennas and assuming
160m or 80m usage)?

You get a greater effective aperture (aka "capture area", and directly
related to "effective length") from the ferrite rod antenna for a given
physical size. This results in a larger signal for a given impinging
field strength. If you had perfect amplifiers, that would make no
difference, but real amplifiers generate noise, so a larger signal
results in a better signal/noise ratio when you're at the level where
the amplifier noise dominates the system noise figure. But if the signal
level is large enough so that atmospheric noise dominates, having a
greater aperture doesn't present any advantage.

As mentioned earlier, there have been a number of construction articles over
the years explaining how a ferrite rod antenna did wonderful things for
160/80 operation. I have wondered if these results are generally valid, or
were the result of the authors' pride in their works, or happened because
the directional null abilities solved a local problem.

Anecdotal reports of "wonderful things" should always be highly suspect,
and placebo effect high on the list of possible causes. It might be
easier to get a good null with a ferrite rod antenna than with a
casually built antenna of some other kind, and that would be a big
potential advantage.

When considering the value of anecdotal reports, consider the widely
reported benefits of various kinds of speaker cable, and the staggering
amount of money that's being extracted from the believers.

Roy Lewallen, W7EL

J. B. Wood wrote:
. . . It's patented so it must work...

Yeah, like U.S. patent 6,025,810, "Hyper-Light-Speed Antenna"
(http://tinyurl.com/h546u).

Roy Lewallen, W7EL

"Roy Lewallen" wrote

If you'd spend a fraction of the time studying that you spend desperately
trying to find something wrong with anything Tom says, you'd have a much
better understanding of how antennas work.

Roy Lewallen, W7EL



Congratulations Roy,
you have nove graduated from "W8JI school of personal mud slinging" when
running out of arguments.
How perceptive: " ...desperately....anything Tom says...."

"Better understanding" - you mean swallowing fallacies you scientwists
proclaim?
I will stick with my understanding of how antennas work and I can measure,
vs. your misapplied theories why it "can't be so".

73 Yuri, K3BU

J. Mc Laughlin wrote:

P-noise is not found on an antenna imbedded in a clump of trees when an
antenna out in the open (many wavelengths from the first antenna) has
P-noise. The follow-on is that since most sites are urban or suburban, few
radio amateurs will experience P-noise.

That does not disagree with anything I said. A lower antenna surrounded
by taller objects is not subject to the same high voltage gradient as
an antenna out in a flat clear field.

P-noise is observed when there is no rain nor thunderstorms, but plenty
of wind. This is suggestive of moving charge discharging into the antenna.

So how does it get there? How does it build up? Where is the spark arc
or sizzle?

Of course, one could define this action as being "corona." Of course, if
one places enough charge on a piece of metal eventually there will be
"corona." Many antennas have a conductive path to earth that makes such an
accumulation of charge unlikely.

The fact is grounded or ungrounded antennas all behave the very same
way. Ask anyone who has yagis on towers. It is a potential difference
between earth and the atmosphere around the antenna. It isn't the
antenna charging up so much differently than earth. It is the
difference in potential between the antenna and the space around the
antenna.

Remember those old tall mast wooden sailing ships soaked with sal****er
and the fire off the yardarms at night?

Your #6 is interesting. Unfortunately, there is so much radiation from
what else is on a tall building that it is difficult to sort out where
excess noise is coming from. An antenna inside of a slightly conductive
radome that is placed a long distance from anything that could radiate might
be different.

You can walk right up to the noise source, and even see the corona at
night. It's very easy to take a FSM with audio monitor or AM receiver
with S meter and walk the roof for strongest noise, and it will
generally take you right to the tallest sharpest object (grounded or
not) on the roof.

The last place you want to be is the tallest antenna on the building.
Get high winds or inclement weather and you will be destined for
noise....grounded antenna or not.

We serviced dozens of repeaters and a few STL or Remote links in the
70's, it was a pattern that repeated.

I have a suggestion. Go to a forum where there are many people with
antennas at various heights, like a contesting reflector. Ask people
who have similar or identical antennas at various heights on a single
tall tower what they observe during high winds, nasty weather, or rain.
The very same wind and the very same moisture is impacting all of the
antennas, but without fail they will tell you the lower antennas are
always much better and the taller antennas are the first to go.

If the P-staic is actually coming from the particles or moisture in air
striking the antenna, and if the same basic sample of weather is at all
the antennas, why are the upper antennas affected more?

If it is the conductor charging, why do plumber's delight antennas or
folded elements with grounded centers have the same noise as insulated
elements?

If it is moisture or particles striking the antenna causing the
problem, why is an insulated antenna with a single sharp protrusion
just as noisey as a bare antenna? Why doesn't the noise follow the
pattern of the particle rate, and why does it occur (as you even seemed
to say) when there is no actual precipitation?

Since I've always had towers taller than 100 feet, and since I've
worked on VHF and UHF systems that had to stay up during storms, I've
spent a lot of time looking at this. I've not found anything that
points to the antenna charging differently than earth or being struck
by charged particles.

73 Tom

wrote:
J. Mc Laughlin wrote:
P-noise is observed when there is no rain nor thunderstorms, but plenty
of wind. This is suggestive of moving charge discharging into the antenna.

So how does it get there? How does it build up? Where is the spark arc
or sizzle?

This is a well known phenomenon in Arizona. What else, besides
charged dust particles, could cause arcing at coax connectors
on a perfectly clear windy day?
--
73, Cecil http://www.qsl.net/w5dxp

Dear Tom:

It appears that two noise mechanisms exist. The two are P-noise and
corona noise. A receiver will experience close to white noise in both
cases. However, corona noise tends to be accompanied by sudden stops and
starts and P-noise starts with a sequence of perceptibly time spaced pops
that increase in rate.

If there is corona off of the top of a structure then it is reasonable
to expect the antennas most close to the corona will "hear" more noise than
the antennas that are farther away (such as below).

It is also to be expected that moving charged particles that are higher
above the ground will carry more charge on the average than charged
particles that are moving near the ground. Depending on the wind and
gradient, I expect that there is a height below which few charged particles
are found when higher above ground charged particles are common.

In short: If one can see corona, it will be the dominate noise source.
If the gradient with altitude is not sufficient for corona, and weather
conditions are such that moving charged particles exist, then out in the
open the higher antennas are expected to have more discharges from moving
charged particles per second and more noise than experienced by lower
antennas.

I have offered an alternative explanation for why, absent corona, higher
antennas might well experience more noise.

Actual precipitation (rain, snow, hail) is not needed for P-noise.
Moving dust particles can carry charge and become charged. The noise does
follow the "pattern of the particle rate." However, as you understand from
other work, when the rate becomes high enough compared to the bandwidth of
the receiver the result is essentially indistinguishable from white noise.
Even with a 400 Hz bandwidth, the onset of P-noise is unique and comprises a
sequence of pops that either die away or increase in rate to produce
prodigious amounts of noise. I have used a time blanking circuit - noise
clipper - and find that it is effective at lower rates. Corona noise does
not seem to have the same temporal characteristics.

A moving charged particle is able to discharge into an insulated
conductor with aplomb. It is the very-close-to-the-antenna sudden
accelerations of charge that produce noise (radio waves). What has shown
promise is the use of slightly conductive coverings. The theory is that the
amplitude of the pop will be reduced because the rate of charge transfer
will be slowed. UV resistant materials that are easy to apply and that are
not expensive seem not to exist. Obviously, too much conductivity would be
ineffective.

Absent actual corona, a noise mechanism is contended that comprises the
sudden transfer of some or all of the charge on a moving charged particle
(that occurs naturally) into an antenna's structure, support or even into
insulation around same.

A near optimum, HF, DX, low-noise receiving antenna is a small,
horizontal, unturned loop antenna with an amplifier that is mounted on a
wood pole having no metal inserts. The pole is some 200 meters from any
exposed metal. The coax that runs up the pole to the amplifier is encased
in conductive, plastic conduit as is the loop's wire. This antenna has
close to a null at the zenith and is omnidirectional in azimuth.


It is contended that what I have observed is not in conflict with what
you have observed with corona discharges. 73 Mac N8TT

P.S. Some months ago you asked about V antennas for low HF or MF use
involving a 300 foot tower. I found that an interesting topic and did some
analysis, which I tried to sent to you. Unfortunately, the E-mail address
did not work. My conclusion, was, as well as I am able to remember, the
same as yours: at the low frequencies involved, the effort did not have a
reasonable pay-back.
--
J. Mc Laughlin; Michigan U.S.A.
Home:
wrote in message
oups.com...
J. Mc Laughlin wrote:

P-noise is not found on an antenna imbedded in a clump of trees when
an
antenna out in the open (many wavelengths from the first antenna) has
P-noise. The follow-on is that since most sites are urban or suburban,
few
radio amateurs will experience P-noise.

That does not disagree with anything I said. A lower antenna surrounded
by taller objects is not subject to the same high voltage gradient as
an antenna out in a flat clear field.

P-noise is observed when there is no rain nor thunderstorms, but
plenty
of wind. This is suggestive of moving charge discharging into the
antenna.

So how does it get there? How does it build up? Where is the spark arc
or sizzle?

Of course, one could define this action as being "corona." Of course,
if
one places enough charge on a piece of metal eventually there will be
"corona." Many antennas have a conductive path to earth that makes such
an
accumulation of charge unlikely.

The fact is grounded or ungrounded antennas all behave the very same
way. Ask anyone who has yagis on towers. It is a potential difference
between earth and the atmosphere around the antenna. It isn't the
antenna charging up so much differently than earth. It is the
difference in potential between the antenna and the space around the
antenna.

Remember those old tall mast wooden sailing ships soaked with sal****er
and the fire off the yardarms at night?

Your #6 is interesting. Unfortunately, there is so much radiation
from
what else is on a tall building that it is difficult to sort out where
excess noise is coming from. An antenna inside of a slightly conductive
radome that is placed a long distance from anything that could radiate
might
be different.

You can walk right up to the noise source, and even see the corona at
night. It's very easy to take a FSM with audio monitor or AM receiver
with S meter and walk the roof for strongest noise, and it will
generally take you right to the tallest sharpest object (grounded or
not) on the roof.

The last place you want to be is the tallest antenna on the building.
Get high winds or inclement weather and you will be destined for
noise....grounded antenna or not.

We serviced dozens of repeaters and a few STL or Remote links in the
70's, it was a pattern that repeated.

I have a suggestion. Go to a forum where there are many people with
antennas at various heights, like a contesting reflector. Ask people
who have similar or identical antennas at various heights on a single
tall tower what they observe during high winds, nasty weather, or rain.
The very same wind and the very same moisture is impacting all of the
antennas, but without fail they will tell you the lower antennas are
always much better and the taller antennas are the first to go.

If the P-staic is actually coming from the particles or moisture in air
striking the antenna, and if the same basic sample of weather is at all
the antennas, why are the upper antennas affected more?

If it is the conductor charging, why do plumber's delight antennas or
folded elements with grounded centers have the same noise as insulated
elements?

If it is moisture or particles striking the antenna causing the
problem, why is an insulated antenna with a single sharp protrusion
just as noisey as a bare antenna? Why doesn't the noise follow the
pattern of the particle rate, and why does it occur (as you even seemed
to say) when there is no actual precipitation?

Since I've always had towers taller than 100 feet, and since I've
worked on VHF and UHF systems that had to stay up during storms, I've
spent a lot of time looking at this. I've not found anything that
points to the antenna charging differently than earth or being struck
by charged particles.

73 Tom

J. Mc Laughlin wrote:

It appears that two noise mechanisms exist. The two are P-noise and
corona noise. A receiver will experience close to white noise in both
cases. However, corona noise tends to be accompanied by sudden stops and
starts and P-noise starts with a sequence of perceptibly time spaced pops
that increase in rate.

Pops are caused by something charging and flashing over. All it takes
to eliminate pops is a leak resistance or a leak choke slow enough to
keep the antenna from charging.

I've never heard the slow popping noise called P-static by anyone I
know, but that doesn't say some people don't call it that.

I have dipole high in the air, and on a clear day with a fair breeze
they will knock someone right on their butt if the feeder is unhooked
and the antenna allowed to charge. It does that dust or no dust,
although nasty weather seems to greatly increase charge rate.

It's easy to see why that happens.

http://www.who.int/peh-emf/publicati...d_Exposure.pdf

There is a significant electric field as we increase height even in
fair weather. Even though that is a very high impedance field, it
doesn't take air movement to charge a high conductor that is
well-insulated.

I have offered an alternative explanation for why, absent corona, higher
antennas might well experience more noise.

True, but a height change of just a few meters on a building or tower
hundreds of meters tall makes a big difference as do sharp compared to
blunt points on an antenna.

During a rainstorm, when most people complain about corona, droplets
from the very same sources are hitting lower and upper antennas. The
noise does NOT follow the pattern or rate of raindrops hitting the
antenna, and the upper antenna is always significantly noisier than the
lower antenna.

Actual precipitation (rain, snow, hail) is not needed for
P-noise.

Of course not. It is a voltage gradient problem.

Moving dust particles can carry charge and become charged. The noise does
follow the "pattern of the particle rate."

I've never seen it do that. But I'll keep watching for it.

P.S. Some months ago you asked about V antennas for low HF or MF use
involving a 300 foot tower. I found that an interesting topic and did some
analysis, which I tried to sent to you. Unfortunately, the E-mail address
did not work.

That's because the email address listed by Google for me is a dead
address. If it was live, it would be useless with spam and virus.

73 Tom

Dear Tom:
Thank you for your ideas and the reference.

Let us leave it that we see things differently. Readers have the
ability to learn from contrasting each of our viewpoints.

I have always included my E-mail address in my communications.

I must to bed - tomorrow is the last lab day of the semester and I
anticipate many questions directed to the proximate final exams.

73, Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
wrote in message
ups.com...
J. Mc Laughlin wrote:

It appears that two noise mechanisms exist. The two are P-noise and
corona noise. A receiver will experience close to white noise in both
cases. However, corona noise tends to be accompanied by sudden stops
and
starts and P-noise starts with a sequence of perceptibly time spaced
pops
that increase in rate.

Pops are caused by something charging and flashing over. All it takes
to eliminate pops is a leak resistance or a leak choke slow enough to
keep the antenna from charging.

I've never heard the slow popping noise called P-static by anyone I
know, but that doesn't say some people don't call it that.

I have dipole high in the air, and on a clear day with a fair breeze
they will knock someone right on their butt if the feeder is unhooked
and the antenna allowed to charge. It does that dust or no dust,
although nasty weather seems to greatly increase charge rate.

It's easy to see why that happens.

http://www.who.int/peh-emf/publicati...d_Exposure.pdf

There is a significant electric field as we increase height even in
fair weather. Even though that is a very high impedance field, it
doesn't take air movement to charge a high conductor that is
well-insulated.

I have offered an alternative explanation for why, absent corona,
higher
antennas might well experience more noise.

True, but a height change of just a few meters on a building or tower
hundreds of meters tall makes a big difference as do sharp compared to
blunt points on an antenna.

During a rainstorm, when most people complain about corona, droplets
from the very same sources are hitting lower and upper antennas. The
noise does NOT follow the pattern or rate of raindrops hitting the
antenna, and the upper antenna is always significantly noisier than the
lower antenna.

Actual precipitation (rain, snow, hail) is not needed for
P-noise.

Of course not. It is a voltage gradient problem.

Moving dust particles can carry charge and become charged. The noise
does
follow the "pattern of the particle rate."

I've never seen it do that. But I'll keep watching for it.

P.S. Some months ago you asked about V antennas for low HF or MF use
involving a 300 foot tower. I found that an interesting topic and did
some
analysis, which I tried to sent to you. Unfortunately, the E-mail
address
did not work.

That's because the email address listed by Google for me is a dead
address. If it was live, it would be useless with spam and virus.

73 Tom