On Sat, 01 Oct 2005 13:42:40 GMT, "Lee"
wrote:


I took my little 1 meter dia ( 10 ft circ ) loop outside lunchtime and
mounted it verticaly 2ft off the lawn and tested it, not expecting anything

Did your "little loop" grow since your first post... it was 1m in
circumfrence in the beginning?

Owen
--

What about a fractal magloop Reg? Should be even smaller. :)

"Reg Edwards" wrote in message
...
The magloop is by far the most efficient of all the antennas of
roughly the same physical size. Both theoretically and in practice. It
will do even better if you can get it well above ground in the
vertical plane.

On Sat, 1 Oct 2005 19:33:49 +0000 (UTC), "Reg Edwards"
wrote:


=======================================
Everybody has heard of the State of Michigan with its capital city of
Detroit. I have always thought of it as an industrial state similar to
my own area of the city of Birmingham and the surrounding Black
Country of England. It is the manufacuring areas which produce the
REAL wealth of this World of ours. Not forgetting the farmers.

Reg, G4FGQ.


Reg, I grew up in Michigan, and spend 6 mo a year here, the other 6 in Florida.
In all the time I've spent in Michigan I wasn't aware that Detroit is the
Capitol. When was it moved from Lansing? Perhaps Mac can help you out in this
dilemma you're creating.

Walt

Dear Reg (G4FGQ):
It is now likely to be past your bed time so this message may be
contemplated in the bright, clear morning.
I have inserted some items below.
--
J. Mc Laughlin; Michigan U.S.A.
Home:

"Reg Edwards" wrote in message
...

"J. Mc Laughlin" wrote

Dear Reg (G4FGQ):

I note with interest that your note was written in the early
afternoon.

==========================================
My Dear J. Mc Laughlin,

Thank you for your interest in my early afternoon state of health. It
is now 19.15 hours and I have just started on a bottle of Sierra
Valley, Californian, Ruby Cabernet.

--- You are commended for your assistance of our unfortunate brethren in
California. A good Midwesterner gives thanks at frequent intervals not to
be in crammed into California or out East. It is appropriate to observe
that the French would have no good grapes were it not for the Californian
growers.


The subject of my communication is: small (much smaller than a
wavelength) - non-resonant (input impedance almost entirely
inductive if one
looks into a single opening in the loop) - horizontal - loop antenna
(no
substances with significant magnetic properties are in the vicinity
of the
loop antenna) - used to receive incident EM waves (which have both E
and H
components). SNRHL receiving antennas

I do not know the definition of a "magloop." Apparently, such a
beastie
comprises a resonant loop antenna.

=======================================
"Magloop" describes a small, single-turn, thick conductor, usually
made from copper water pipe, circular, hexagonal or square in shape,
loop. The two ends of the loop are connected together via a variable
capacitor. The capacitor tunes the inductance of the loop to a
resonant frequency at which everything happens.

The term "magnetic" arises because the near-field of a transmitting
loop is mainly magnetic as distinct from the electric field. On
receive it is more sensitive the magnetic field than the electric
field.

--- I am obliged to you for providing a definition of "magloop." The
critical element of the definition seems to be that a magloop is a loop that
is resonated by a reactance.
--- I am puzzled by your observation with respect to the term "magnetic" in
conjunction with a loop antenna (presumably a loop antenna, whether or not a
magloop). You appear to be saying that a loop antenna is more sensitive to
the H field than to the E field of an incident EM field.
--- Relative to you, I have only been dealing with antennas a short 50
years. However, in that time, I have only encountered antennas that extract
a signal from an EM field where the ratio of E to H is well established. My
graduate professor, who recently passed away and who wrote The Book on
antennas, never mentioned antennas that inherently were sensitive to one
component of the incident EM wave.
--- Perhaps what you were saying is that one can predict the polarization of
an EM wave launched from a loop antenna from knowing its geometry and the
observer's orientation with respect to the geometry. This is also true for
a doublet and a number of other antennas.

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

No knowledgeable person would disagree that a single tuned
network with
a Q of 1000 is "narrow."

My interest in SNRHL receiving antennas comes from an interest
in
practical HF receiving antennas that are resistive to types of noise
that
appear only to be present at isolated, open, rural,
otherwise-low-noise
sites. The noise involved does not occur in urban areas or even
rural sites
with many trees.

=====================================
The noise in rural, open, oceanic areas is just the same sort as in
built-up, residential, city and industrial areas. It is all random but
there is just a lot less of it.

--- I do not have the verbal skill of Richard Clark, who could find an
elegant way to say what needs to be said. Dear Reg, you are wrong. You are
wrong because your long and extensive carrier has not placed you in the
sites described. Had you spent time out in the sticks, bare of same, you
would have encountered the discharging of charged particles into the antenna
you were using (or discharging into nearby conductors) producing a
prodigious amount of excess noise. The particles are sometimes dust
particles, sometimes water droplets, and sometime snow. By far, the
greatest limitation on the performance of an HF receiving site in rural,
open country is the sudden appearance of this noise. Even at VHF, it is
sometimes a limiting factor. State Police posts in Michigan have sometimes
not been able to communicate with 100 watt mobiles that were less than 300
meters away because of this noise appearing in a snow storm. (Movement to
much higher frequencies and other strategies have alleviated their problem.)
--- My experience does not extend to extensive receiving sites out to sea.
They might, it they exist at all, not encounter the excess noise. It is
also clear that high air humidity may serve to reduce the excess noise.
--- Please add to your vast reservoir of knowledge something new.
---

An antenna of any sort is just as sensitive to noise as it is to
signals provided both noise and signals are coming from the same
direction and elevation.
======================================

Consider some of the excellent wine from Michigan this evening.
This
state, with a coastline almost the same length as that of the island
of
Great Britain, produces some excellent products for your enjoyment.

=======================================
Everybody has heard of the State of Michigan with its capital city of
Detroit. I have always thought of it as an industrial state similar to
my own area of the city of Birmingham and the surrounding Black
Country of England. It is the manufacuring areas which produce the
REAL wealth of this World of ours. Not forgetting the farmers.

--- Well said! Michigan has had the most productive industry in the world.
It also has some of the most productive agricultural land - especially for
being in the north. However, Michigan (and others) are going through a
major change. The advent of fast, inexpensive communication and
transportation have seen the movement of vast numbers of manufacturing jobs
to areas where wages are low. Many square miles of factories have been
pulled-down to bare ground. (Taxes are thus reduced - often next to
impossible to sell the land because of unknown pollutants from 90 or more of
industrial use.) Ascendant in Michigan are jobs that produce intellectual
property, that are involved with higher education, and that are involved
with medicine including research. The new worker is different.

--- While Detroit is still the largest city, the capital is in Lansing.

Never having had the opportunity to visit Michigan it has not occurred
to me that the land could also grow grapes and produce wine.
(Actually, we do produce respectable wine here in cool-climate
industrial England. But not much of it.)

---Michigan is almost surrounded by very large lakes that mollify the
weather. The west coast of Michigan, in particular, has very productive
fruit farming. It is quite possible that few of Michigan's grape products
are exported. Thank you for considering another of our products for your
evening repast.

It is now 20.00 hrs and too late to go shopping at my local
super-market. Nevertherless, at my next visit I shall keep my eyes
open for "Michigan" on the wine bottle labels.
----
Reg, G4FGQ.

"Owen Duffy" wrote in message
...
On Sat, 01 Oct 2005 13:42:40 GMT, "Lee"
wrote:


I took my little 1 meter dia ( 10 ft circ ) loop outside lunchtime and
mounted it verticaly 2ft off the lawn and tested it, not expecting
anything

Did your "little loop" grow since your first post... it was 1m in
circumfrence in the beginning?

Owen
--

You`re right Owen, i did state that didn`t i?...it was a typo of course,Heh
heh, it should read "10Foot circumference approx 1 meter dia".......

Thanks for telling me ......

Lee......G6ZSG........

"Reg Edwards" wrote in message
...
Hello Lee,

Thanks for letting me know that by giving your magloop half-a-chance
it performs according to expectations.

You have also demonstrated that the G5RV is not so hot as it is made
out to be by salesmen and they who have never tried anything else.
snip

Well, for me Reg, the halfsize G5RV was the only multi band antenna that i
could squeeze into my garden...and the bandwidth of the loading coils for 80
is below my expectations..... that`s apart from the fact the loading coils
knocked out 40...ho-hum time for a better antenna that isn`t an
eyesore...and works better as a bonus.....
On VHF, beams and quadloops are no problem for 6m even, but HF is a whole
new ballgame....had i the space, i would continue with quadloops for
HF....but!!!......(shakes head).

Are you using the small internal coupling loop, about 1/5 diameter of
main loop, to match to a 50-ohm feedline? This is the best and most
simple way to go,

No. i`m using a `gamma` match, if you can call it that....the matching loop
comes next.
Wonder if a coaxial gamma match would work as i`m a staunch
believer....(could put that principle to use for the capacitor tuning
instead of a butterfly variable......)
Can`t get on with other types of loading, too fiddly!.

Regards....

Lee...G6ZSG.......



A different ratio small loop diameter is needed for other feedline
impedances. The circuit behaves as if the turns ratio on a
transformer is being changed.

Let us know how your experiments proceed.
----
Reg, G4FGQ.

"LT" wrote in message
...
Hi Lee,

I'm a little confused about the bandwidth that you're getting. Maybe it
can be attributed to losses which widen the SWR bandwidth. That's not
necessarily a bad thing. I have used an AEA IsoLoop antenna that is
about the same size as your loop antenna but has a low loss butterfly
capacitor for tuning 10-30 MHz. On 20 meters the bandwidth is only about
20 or 30KHz(can't remember exactly since I haven't used it for a couple
of years). It works great if you park yourself on a frequency but it is
a pain to use for hunt and pounce.

Yes, of course that should have read 2.5 : 1 SWR which is better than my
`loaded` half size G5RV on 80 at about 100kcs 2.5 : 1 SWR.......

Besides the null using vertical polarization, is it possible that for
your local friend you may have been cross-polarized. Usually direct wave
cross-polarization is on the order 20db which accounts for the 2 to 3 S
units of change from vertical to horizontal.

My `friend has a quarter wave vertical for 20 and the loop was physically
vertical ....also, my G5RV is sloping......

Have fun with your new toy!

Thanks, i am...... ;-)

Lee....G6ZSG......


73 LT
snip

What about a fractal magloop Reg? Should be even smaller. :)

This is a case of a fractal GUARANTEED to perform worse than the basic
antenna in all respects.

That is unless a simple circle can be considered to be a
zero-zero-order fractal.

Walt,

We are all sentimentally attached to the area where we were born. I
find it intriguing you were brought up in the same sort of industrial
region as I was dragged up in. There are a few descriptive paragraphs
in "A bit about Reg" in my website.

Please forgive me for assuming the largest city of Detroit to be the
political capital of Michigan when it is actually Lansing.

Again there is a similarity. The political capital of Warwickshire is
not the largest city of Birmingham but the small ancient town of
Warwick with its castle, not far from Shakespeare's
Stratford-upon-Avon.

Is Michigan named after an Indian tribe?
----
Reg.

On Sun, 02 Oct 2005 05:47:46 GMT, "Lee"
wrote:


Yes, of course that should have read 2.5 : 1 SWR which is better than my
`loaded` half size G5RV on 80 at about 100kcs 2.5 : 1 SWR.......

What is a "'loaded' half size G5RV"?

Googling for info, I see a few suppliers with loading coils for a half
size G5RV (complete with instructions), but could not find an article
with physical dimensions and loading coil characteristics.

Is this a "proprietary" antenna, not open to independent analysis.

In its "normal" mode, a (full size) G5RV has feed system losses on
160m like cricket scores. Intuition suggests that a half-size G5RV
(where everything is scaled to 50%) will have similarly appalling
performance on 80m.

Has anyone seen details of the loading coils for this "loaded
half-sized G5RV', or models of its performance?

Owen
--