Noise level between two ant types
 

Jim - NN7K wrote:
Not to mention that noise is normally a phenonmen
of the Vertical Plane (which , depending on how
steep your inverted "vee" is, will contain some
vertical component, while the yagi/quad is
Horizontal to the plane. This has been a factor
on vhf for years, as noise levels tend to peak
at 6 meters (50 MHz). The MAIN reason that F.M.
is Vertical polarized is that for mobiles, it is
easy to construct an omni-directional antenna.
Most vhf manuals detail this effect! Jim NN7K

Dunno...I don't see much difference as far as the polarity
of the antenna. It's more the polarity of the noise source,
and it's radiator. I've got both horizontal and vertical yagi's
on 2m, and I've seen many times when the local line noise
was much worse when horizontal. But I blame that on the
noise being radiated mainly by horizontal power lines.
I see cases of noise with both polarities, or mostly
vertical, or mostly horizontal. Just depends on the source
antenna. You usually see appx 20db attenuation when
cross polarized.
As far as Ken's loop vs inv vee, if the vee is picking up more
noise, that just means the vee is the best antenna at picking
up that particular noise and at that direction and angle.
If he were to transmit on the two antennas, and receive
them from the noise source, using the sources antenna,
the vee would be received the strongest more than likely.
It's all reciprical. Noise is rf just like any other signal, and
obeys the same rules. If a certain antenna picks up more
rf of any type, noise, or desired, it's the best antenna of the
bunch to receive that source of rf. Thats one reason why I
often chuckle about "noise problems".. As long as it's not
local or common mode pickup from the shack, that just means
the antenna is working, and doing what it's supposed to do.
MK

Noise level between two ant types
 

"Cecil Moore" wrote in message
y.net...
wrote:
You can a call me a liar if you like, but it doesn't change the facts.

Being ignorant doesn't make you a liar. The fact is that
many hams have experienced charged particle noise. Your
denial of such doesn't change the known facts.

The meaning of most of your posting escapes me so I will
just summarize my position.

When I lived in the Arizona, clear-sky wind-driven charged
dust particles transferred lots of energy to my bare-wire
G5RV. It caused arcing whether the outside braid was grounded
or not. It only happened when the wind was blowing and
the humidity was very low.

I'm not sure what your point of disagreement is so help
me out.



Youze guyz are arguing about two cases of "arcing" and going off on
tangents.

First case is as Cecil has experienced and 'splained, is the static
electricity charge buildup and corresponding noise/discharge on conducting
"things" due to charged particles - aka rubbing the glass rod with furry
animal coat. The part (antenna) gets charge from the "rubbing" by the
particles, air, whatever...., builds up voltage and is looking for discharge
across anything that provides jumping points for the voltage accumulated.
This is the case of clear Arizona skies, with no clouds in sight, just wind
doing it's "thing". W8JI might not believe it, but it IS the fact.

Second case is, as it was hotly discussed on Contest and other reflectors,
and first mentioned by VE3BMV, W0UN, W4ZV and others, in conjunction with
lightning and protection against it - is the static electricity charge
buildup due to the clouds "rubbing" in the air and creating huge static
charge between the clouds and the earth ground and objects "residing" on
ground and connected to it. There the highest , mostly grounded, objects get
"first crack" at the "touching" the voltage gradient generated by the static
electricity buildup. If there is a sharp object, it will start "acting" by
generating corona and "peacefully" discharging the potential. If it can't
keep up with rate of "peaceful" charge, it will invite lightning strike. The
corona can be visible at the times, or it doesn't have to be.
Then we get cases when the high antenna is the highest object and will be
the "discharger" and the noisiest one. That appears to discharge the charge
from the area (space) in the vicinity of the high (object) antenna -
umbrella. You can look at it as a capacitor plate, collecting charge from
the space around it. Lower antennas get benefit of discharged space and are
quiet. This is especially noticeable with stacked antennas. The top one
would be typically 20/9 noise - hash, the lower one would be dead quiet.
The same then applies when you have higher object than antenna in question,
that antenna could be quiet, but when (beam) is aimed at the higher object
(the static discharger) it can receive noise, but at much lower strength.

This umbrella effect seems also work as a lightning prevention by
discharging the space in the vicinity of the structure and preventing
critical buildup of voltage causing creating of leader and inviting
lightning strike (99.9%). I and others have noticed practical elimination of
lightning strikes to our installation when sporting tall, grounded towers
with large antennas (capacitor plates). They seem to bleed the deadly
potential from the air "sandwich" between the sky (clouds) and ground and
objects under the "umbrella" and making lightning look at pointy grounded
objects before and after our "ugly" antennas and discharge their deadly
megawatts there.
So large antennas on tall towers - GOOD to repell lightning. Pointy, sharp
objects - BAAAAD, they attract lightning. So, one can protect his QTH and
radio junk by either inviting lightning to strike the lightning arresters
and hopefully conduct them to ground, or better, repelling it by the Antenna
Umbrella - the biggest mother antenna (capacitor plate) on the tallest
possible and well grounded tower (no protruding VHF vertical pointy junk
above) you can put up.

Scientwists might not find this believable, but those with big towers and
large grounded antennas noticed remarkable absence of direct lightning
strikes vs. when previously sporting pointy verticals or towers without
antennas on the top.
When I had my TH6 at 60 ft. and above it, way up 2m Ringo Ranger on a mast,
I got visited by direct lightning trice within 2 years. When put up Big
Bertha with 60 ft boom Razors, never again over 10 years. Not very
statistically scientific, but very noticeable. Same experienced by W0UN,
W0ZV and others.

Soooo, the judge's verdict is: Cecil is right, W8JI is partially right, jury
to judge by the above 'splanation of this humble servant. :-)

I hope this clears some static static.

--
Yuri Blanarovich, K3BU, VE3BMV

Noise level between two ant types
 

Cecil Moore wrote:
When I lived in the Arizona, clear-sky wind-driven charged
dust particles transferred lots of energy to my bare-wire
G5RV. It caused arcing whether the outside braid was grounded
or not. It only happened when the wind was blowing and
the humidity was very low.

But that effect is common no matter where we live. As I've said several
times, a high dipole here for 160m charges enough to knock you on your
rear on a calm sunny day if the coacial line is well insulated from
ground.

It is not wise tol have a large high antenna that was well-insulated
from ground, since the accumulated charge can suddenly discharge
through a series capacitor and damage equipment.

Utility companies must ground unused wires that run for miles to
prevent build up of charge, so that is not something that just occurs
in arid climates.

Do you agree that a charged particle will transfer energy
to the bare wire in a dipole when it touches it? If not,
why not?

Of course it will IF it is at a different potential than the wire.

If the antenna were link coupled, do you agree that the
above transferred energy will try to equalize between the
two dipole elements? If not, why not?

Of course it will.

Do you agree that the equalizing of the charges between
elements would cause a current to flow through the link?
If not, why not?

Of course it will.

I disagree wth your contention that the link, if the noise comes from
each particle hitting the antenna, will reduce noise. That's the part
that makes no sense.

Maybe you can explain why the link (or folded element) would reduce
that noise.

73 Tom

Noise level between two ant types
 

On 13 Jun 2006 01:37:57 -0700, wrote:


Cecil Moore wrote:
When I lived in the Arizona, clear-sky wind-driven charged
dust particles transferred lots of energy to my bare-wire
G5RV. It caused arcing whether the outside braid was grounded
or not. It only happened when the wind was blowing and
the humidity was very low.

But that effect is common no matter where we live. As I've said several
times, a high dipole here for 160m charges enough to knock you on your
rear on a calm sunny day if the coacial line is well insulated from
ground.

It is not wise tol have a large high antenna that was well-insulated
from ground, since the accumulated charge can suddenly discharge
through a series capacitor and damage equipment.

I have a low, 30 feet or so, 80 meter dipole fed with ladderline,
through an mfj 989c tuner. Hot humid clime (Texas). Is the ground wire
on the back of the tuner, going to a ground rod, enough to bleed off
electrical build up?

bob
k5qwg



Utility companies must ground unused wires that run for miles to
prevent build up of charge, so that is not something that just occurs
in arid climates.

Do you agree that a charged particle will transfer energy
to the bare wire in a dipole when it touches it? If not,
why not?

Of course it will IF it is at a different potential than the wire.

If the antenna were link coupled, do you agree that the
above transferred energy will try to equalize between the
two dipole elements? If not, why not?

Of course it will.

Do you agree that the equalizing of the charges between
elements would cause a current to flow through the link?
If not, why not?

Of course it will.

I disagree wth your contention that the link, if the noise comes from
each particle hitting the antenna, will reduce noise. That's the part
that makes no sense.

Maybe you can explain why the link (or folded element) would reduce
that noise.

73 Tom

Noise level between two ant types
 

Bob Miller wrote:

I have a low, 30 feet or so, 80 meter dipole fed with ladderline,
through an mfj 989c tuner. Hot humid clime (Texas). Is the ground wire
on the back of the tuner, going to a ground rod, enough to bleed off
electrical build up?

Almost anything is enough to do that. The charge rate is extremely low.


My 318 foot tall insulated tower had a measured charge rate in the
ten's of milliamperes as measured during approaching thunderstorms.

Of course taking care of a lightning bolt or EMP from a lightning
strike someplace around the area is another story.

73 Tom

Noise level between two ant types
 

wrote:
Cecil Moore wrote:
When I lived in the Arizona, clear-sky wind-driven charged
dust particles transferred lots of energy to my bare-wire
G5RV. It caused arcing whether the outside braid was grounded
or not. It only happened when the wind was blowing and
the humidity was very low.

But that effect is common no matter where we live. As I've said several
times, a high dipole here for 160m charges enough to knock you on your
rear on a calm sunny day if the coaxial line is well insulated from
ground.

During the "H Field Antennas" thread, you said the following:
************************************************** *************
Reg Edwards wrote:
Precipitation static, eg., from highly charged raindrops and fine snow
or fine sand, impinging on the antenna wire, just causes an increase
in receiver white noise level. It can be reduced but not removed by
using a very thickly insulated antenna wire, like the inner conductor
of a coaxial cable complete with its polyethylene jacket.
----
Reg.

W8JI replied:
I've never seen a case of precitation static occuring that way.

In every single case I've seen, whether on tall buildings, tall towers,
or antenna hear earth, it has always been corona discharges from the
antenna or objects near the antenna. ... 73 Tom

************************************************** **************

I have only noticed the charged particle arcing in Arizona when
the wind was blowing and that is what I am reporting.

It is not wise to have a large high antenna that was well-insulated
from ground, since the accumulated charge can suddenly discharge
through a series capacitor and damage equipment.

Where does the accumulated charge come from if not from charged
particles? If the antenna is link coupled, the charge equalizes
between the two dipole elements and, in my experience, doesn't
arc.

Do you agree that a charged particle will transfer energy
to the bare wire in a dipole when it touches it? If not,
why not?

Of course it will IF it is at a different potential than the wire.

If the antenna were link coupled, do you agree that the
above transferred energy will try to equalize between the
two dipole elements? If not, why not?

Of course it will.

Do you agree that the equalizing of the charges between
elements would cause a current to flow through the link?
If not, why not?

Of course it will.

Seems we are in agreement that charged particle RF noise can
therefore be picked up by a receiver as Reg says above. It is
only logical that it will be worse when the wind blows causing
more charged particles to encounter the antenna wire. And,
as shown below, it is only logical that a folded dipole would
transfer less of that noise to the link than a non-folded dipole.

I disagree with your contention that the link, if the noise comes from
each particle hitting the antenna, will reduce noise. That's the part
that makes no sense.

In my experience, it eliminated the arcing. Thus it eliminated
the *AURAL* arcing noise that my ears were hearing. Why does that
make no sense? I was very clear that my receiver was off and
disconnected at the time and that I made no RF noise measurements.
A short, or 4:1 voltage balun, or choke, or link across the
connector eliminated the *AURAL* arcing noise.

Maybe you can explain why the link (or folded element) would reduce
that noise.

Seems you confused my statements about aural noise with RF
noise. I have previously said I didn't measure the RF noise.

In any case, please see the pictures below to understand why
a folded element redirects the charge equalization process
away from the link.

The process of equalizing the charge on the non-folded dipole
elements causes RF noise across the link which is picked up by
the S-meter on the receiver. I observed that many times in AZ
and wish I had made some measurements. The S-meter reports a
higher level of charged particle noise during high wind
conditions and dry-air snowstorms.

Please explain what it is about the following that you don't
understand.

1. The equalizing of the element charges on a link coupled
dipole will cause a current to flow through the link resulting
in higher RF noise readings on the S-meter during high wind
conditions when more charged particles are encountering the
antenna wire.

2. Turning the dipole into a folded dipole (or loop) gives a
preferred localized path for the equalization of the charge.
Not nearly as much RF noise current flows through the remote
link.

Maybe a picture would help. Here's a non-folded dipole with a
charge hitting it. In order to equalize charge with the other
element, part of the charge must flow down the transmission
line, through the link, and back up the transmission line to
the other dipole element. Virtually all of the pulsed charge
equalization process goes through the link.

---------CH----+ +---------------
| |
/ /
| |
link

************************************************** **************


+--------------------------------+
+--------CH----+ +---------------+
| |
/ /
| |
link

Here's a folded dipole with a charge hitting it in the same
relative place. What is the most efficient preferred path for
equalizing the charge with the other element? Not down the
transmission line and through the link but simply straight
through the antenna wire. Hint: Charge would rather take
the 50 foot path of least resistance than a 200 foot path
of most resistance.

Eureka! The folded dipole is less noisy during high wind
conditions than is the non-folded dipole because most of
the charge equalization takes place locally through the
antenna wire and not remotely through the link.

BTW, thanks for forcing me to think this through in detail.
--
73, Cecil http://www.qsl.net/w5dxp

Noise level between two ant types
 

Bob Miller wrote:
I have a low, 30 feet or so, 80 meter dipole fed with ladderline,
through an mfj 989c tuner. Hot humid clime (Texas). Is the ground wire
on the back of the tuner, going to a ground rod, enough to bleed off
electrical build up?

If there is a DC path to ground from *BOTH* sides of the
dipole, the answer is yes. But, looking at the 989c
schematic, I don't see a DC path to ground from one of
the balanced line outputs.
--
73, Cecil http://www.qsl.net/w5dxp

Noise level between two ant types
 

Cecil Moore wrote:
Bob Miller wrote:
I have a low, 30 feet or so, 80 meter dipole fed with ladderline,
through an mfj 989c tuner. Hot humid clime (Texas). Is the ground wire
on the back of the tuner, going to a ground rod, enough to bleed off
electrical build up?

If there is a DC path to ground from *BOTH* sides of the
dipole, the answer is yes. But, looking at the 989c
schematic, I don't see a DC path to ground from one of
the balanced line outputs.

I forgot to say that your high humidity probably provides
a path to ground from the other tuner terminal. It was
only during super low humidity conditions in the Arizona
desert that I experienced the arcing process during
high winds.
--
73, Cecil http://www.qsl.net/w5dxp

Noise level between two ant types
 

Cecil Moore wrote:
wrote:
Cecil Moore wrote:
When I lived in the Arizona, clear-sky wind-driven charged
dust particles transferred lots of energy to my bare-wire
G5RV. It caused arcing whether the outside braid was grounded
or not. It only happened when the wind was blowing and
the humidity was very low.

But that effect is common no matter where we live. As I've said several
times, a high dipole here for 160m charges enough to knock you on your
rear on a calm sunny day if the coaxial line is well insulated from
ground.

In the text above I was responding to the charging and arcing from a
floating antenna, NOT to the mechanism Reg was talking about below. I
have NO problem with the wire charging and arcing. But I've NEVER seen
a situation where particles directly hitting the antenna make noise,
which is what Reg was talking about below....

During the "H Field Antennas" thread, you said the following:
************************************************** *************
Reg Edwards wrote:
Precipitation static, eg., from highly charged raindrops and fine snow
or fine sand, impinging on the antenna wire, just causes an increase
in receiver white noise level. It can be reduced but not removed by
using a very thickly insulated antenna wire, like the inner conductor
of a coaxial cable complete with its polyethylene jacket.
----
Reg.

W8JI replied:
I've never seen a case of precitation static occuring that way.

In every single case I've seen, whether on tall buildings, tall towers,
or antenna hear earth, it has always been corona discharges from the
antenna or objects near the antenna. ... 73 Tom

************************************************** **************

I have only noticed the charged particle arcing in Arizona when
the wind was blowing and that is what I am reporting.

It is not wise to have a large high antenna that was well-insulated
from ground, since the accumulated charge can suddenly discharge
through a series capacitor and damage equipment.

Where does the accumulated charge come from if not from charged
particles? If the antenna is link coupled, the charge equalizes
between the two dipole elements and, in my experience, doesn't
arc.

Why do you think it is the particle that make noise or even that they
are necessary?

Allowing what you say is true, then you are arguing against yourself.
As I understand it:

1.) You say the particles make the noise as each individual particle
hits the antenna.

2.) You say grounding the antenna eliminates that noise.

There is an obvious conflict in those two ideas. Grounding the element
for DC will not reduce the rate the rate of energy transfer to the
antenna from particle, it can only INCREASE it by preventing long-term
charging of the antenna closer to the potential of the particles.

73 Tom

Noise level between two ant types
 

On Tue, 13 Jun 2006 15:43:29 GMT, Cecil Moore
wrote:

Cecil Moore wrote:
Bob Miller wrote:
I have a low, 30 feet or so, 80 meter dipole fed with ladderline,
through an mfj 989c tuner. Hot humid clime (Texas). Is the ground wire
on the back of the tuner, going to a ground rod, enough to bleed off
electrical build up?

If there is a DC path to ground from *BOTH* sides of the
dipole, the answer is yes. But, looking at the 989c
schematic, I don't see a DC path to ground from one of
the balanced line outputs.

I forgot to say that your high humidity probably provides
a path to ground from the other tuner terminal. It was
only during super low humidity conditions in the Arizona
desert that I experienced the arcing process during
high winds.

I can't recall seeing any gap-sparking here in the San Antonio area.
When it's hot, it's usually pretty humid, too.

bob
k5qwg