Reg Edwards wrote:

There exist statistics of AVERAGE field strength noise levels
experienced in cities, small towns and in the open countryside. I have
forgotten where to find such statistics but Google may help.

The statistics depend very much on frequency. They vary greatly between
ELF and HF. Noise levels decrease by crudely 10 dB or 20 dB per octave
or decade increase in frequency.


ITU Recommendation ITU-R P.372-8, 'Radio Noise'. This document replaces
and updates the old CCIR Report 322, which was the source for most of
the information on radio noise in the amateur handbooks.

The paper is available as a download from ITU, but they want 36 Swiss
Francs for it (about $28):
http://www.itu.int/rec/R-REC-P.372-8-200304-I/en



--
73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Reg: Your making such an obviously false statement calls into question
all of your pronouncements.
There is not a single student in my University (or any other similar
institution that I know of) who will graduate without providing many
demonstrations of their significant arithmetic and mathematical ability.
Your veracity is gone.

Mac N8TT
--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Reg Edwards" wrote in message
...


==========================================

Arithmetic is not taught in Western schools and universities any more.
Even teachers are innumerate!
----
Reg.

On Sun, 5 Feb 2006 22:50:55 -0500, "J. Mc Laughlin"
wrote:

Reg: Your making such an obviously false statement calls into question
all of your pronouncements.
There is not a single student in my University (or any other similar
institution that I know of) who will graduate without providing many
demonstrations of their significant arithmetic and mathematical ability.
Your veracity is gone.


C'Mon Mac,

Reggie has been doing this so many years, it's his trademark schtick.
To give Reggie credit where credit is due, can be found in a
remarkable body of work of programs. Unfortunately, this
accomplishment is seriously tipped out of balance when he scorns his
audience as software addicts.

Instead of teaching them Kelvin's principles by example, we get his
poor English stagings of Le Misanthrope de Moliere.

One of my favorite irascible English characters is Dr. Samuel Johnson,
but his ire is tempered with a faith in humanity:
"this boy rows us as well without learning, as if he could sing
the song of Orpheus to the Argonauts, who were the first sailors.'
He then called to the boy, 'What would you give, my lad, to know
about the Argonauts?' 'Sir (said the boy,) I would give what I
have.' Johnson was much pleased with his answer, and we gave him a
double fare. Dr. Johnson then turning to me, 'Sir, (said he) a
desire of knowledge is the natural feeling of mankind; and every
human being, whose mind is not debauched, will be willing to give
all that he has to get knowledge.' "

73's
Richard Clark, KB7QHC

"Bob Bob" wrote
I would also
like to get an idea how "critical" it is to make sure ones antenna
truly
is horizontal (eg not an inverted V or quad loop) if noise is the
greatest concern.

One would assume you also get a similar affect of "less horizontal
noise" from the actual noise source for the same reason. eg power
lines
radiate well upwards but not so well in groundwave.
========================================
Bob,

The angle of the 'horizontal' dipole relative to the horizontal,
whether it is an inverted-V or not, makes negligible difference to the
amount of noise it collects. It is non-critical in this respect.

The incoming, mainly distant noise comes in from all directions and
angles and is randomly polarised. Except, that is, for locally
generated noise, which is mainly a vertically polarised ground-wave
and from low angles to which the horizontal dipole is quite
insensitive.

Noise radiated from nearby elevated power lines is probably randomly
polarised and is collected in similar proportions by both horizontal
and vertical antennas. When a power line is half-mile or more away I
would guess that the received noise reverts to vertically polarised
groundwaves which at HF are rapidly attenuated. The horizontal waves
are even more rapidly attenuated.

Noise can be studied only from its statistical probability
distributions versus direction, angle, frequency, receiver bandwidth
and time. The opinions and anecdotes of individuals matter only to the
inviduals concerned and their locations on the Earth's surface.
----
Reg.

Roy Lewallen wrote:


A step attenuator which is completely adequate for HF and can easily
resolve 1 dB can be made from a few cheap slide switches, some PC board
material, and a handful of ordinary 5% quarter watt resistors. Detailed
instructions can be found in numerous sources, including the Web -- a
Google search brought a large number of hits, the first of which was
http://www.arrl.org/tis/info/pdf/9506033.pdf. But I'm afraid that this
level of homebrewing is beyond the interest if not the ability of the
majority of today's amateurs.

Got it - Thanks, Roy!

- 73 de Mike KB3EIA -

Reg, G4FGQ wrote:
"The angle of the "horizontal" dipole relative to the horizon, whether
it is an inverted V or not, makes negligible difference to the amount of
noise it collects."

It could be taken to the extreme. Rotated 90-degrees, the horizontal
wire becomes a vertical wire. On its way to becoming a vertical wire, it
is a sloping wire. The sloping wire responds with a vertical component
in addition to its horizontal component. The sum of these components
make up the wire`s total response.

To the best of my knowledge, Reg hit the nail squarely on the head in
the rest of his posting about noise radiation and reception.

Best regards, Richard Harrison, KB5WZI

Dear Richard:
You have said it so well!
I fell for the taunt of the tar-baby.
Thank you for the literate and appropriate quote from Johnson. For some
unexplainable reason, I once read all of Boswell's journals. I had more
time in those days.
73 Mac N8TT

--
J. Mc Laughlin; Michigan U.S.A.
Home:
"Richard Clark" wrote in message
...
On Sun, 5 Feb 2006 22:50:55 -0500, "J. Mc Laughlin"
wrote:

Reg: Your making such an obviously false statement calls into
question
all of your pronouncements.
There is not a single student in my University (or any other similar
institution that I know of) who will graduate without providing many
demonstrations of their significant arithmetic and mathematical ability.
Your veracity is gone.


C'Mon Mac,

Reggie has been doing this so many years, it's his trademark schtick.
To give Reggie credit where credit is due, can be found in a
remarkable body of work of programs. Unfortunately, this
accomplishment is seriously tipped out of balance when he scorns his
audience as software addicts.

Instead of teaching them Kelvin's principles by example, we get his
poor English stagings of Le Misanthrope de Moliere.

One of my favorite irascible English characters is Dr. Samuel Johnson,
but his ire is tempered with a faith in humanity:
"this boy rows us as well without learning, as if he could sing
the song of Orpheus to the Argonauts, who were the first sailors.'
He then called to the boy, 'What would you give, my lad, to know
about the Argonauts?' 'Sir (said the boy,) I would give what I
have.' Johnson was much pleased with his answer, and we gave him a
double fare. Dr. Johnson then turning to me, 'Sir, (said he) a
desire of knowledge is the natural feeling of mankind; and every
human being, whose mind is not debauched, will be willing to give
all that he has to get knowledge.' "

73's
Richard Clark, KB7QHC

Regardless of its noise properties, a quarter-wave and higher vertical
radiates more low-angle power than a half-wave horizontal dipole.
There's no argument. If you can't be heard then you can't work 'em.

Although a quarter-wave vertical radiates less power at high angles,
it can still be heard quite well because propagation distances covered
are relatively short.

The vertical is omni-directional. The dipole is not.

Skip-distances are the same for both vertical and horizontal. The
Ancient Greeks Geometry rules.

Therefore, the situation is biassed in favor of the vertical.

The dipole wins only when the local noise level is much higher than
atmospheric noise. If you live in or near a city then its your hard
luck. Most of us do!
----
Reg.

Mike Coslo wrote:
Roy Lewallen wrote:


A step attenuator which is completely adequate for HF and can easily
resolve 1 dB can be made from a few cheap slide switches, some PC
board material, and a handful of ordinary 5% quarter watt resistors.
Detailed instructions can be found in numerous sources, including the
Web -- a Google search brought a large number of hits, the first of
which was http://www.arrl.org/tis/info/pdf/9506033.pdf. But I'm afraid
that this level of homebrewing is beyond the interest if not the
ability of the majority of today's amateurs.


Got it - Thanks, Roy!

- 73 de Mike KB3EIA -

You're very welcome.

The reason for my rather grumpy comment at the end is that I've
recommended countless times for many years that people interested in
evaluating antennas build a simple step attenuator -- an evening
project. It allows you to make direct, quantitative comparisons between
two antennas -- yours or someone else's, as well as calibrate your "S"
meter. But to date, I've never gotten an iota of feedback that a single
person has actually taken the trouble to build one. Rather, they
continue to debate, ad nauseum and without any meaningful data, whether
one antenna is better than the other, or at best quote differences in
"S-units" read from their meters, without the foggiest idea how many dB
it might represent or how different it is from someone else's meter (or
from the same meter on a different band or a different part of the
scale). The conclusion I've reached is that A) Hams would much rather
argue than actually determine the facts, or B) The vast majority are
unable to build a homebrew project consisting of slide switches, circuit
board material, and resistors. I'm afraid both are probably true.

Maybe you'll be the first to actually build one. If so, please drop me
an email and let me know -- it'll make my day!

Roy Lewallen, W7EL

"Roy Lewallen" wrote
The reason for my rather grumpy comment at the end is that I've
recommended countless times for many years that people interested in
evaluating antennas build a simple step attenuator -- an evening
project.

========================================

Roy, to cheer you up, many years back I made one in a diecast
Eddystone box. The last decade was in 0.001 dB steps. It was intended
only up to 5 MHz.

It was used to determine the attenuation/temperature coefficients of
oceanic, submarine coaxial cables, 26 miles long, in tanks at the
cable factory. Temperature was changed by dumping a ton of ice into
the tank, obtained from Billingsgate, London, fish market. I think the
fish market is still in Billingsgate but the attenuator has long since
disappeared. Perhaps the knobs still exist somewhere. Very sad!
----
Reg.