In article AoAnf.6140$Jz6.1180@trnddc06,
"Dale Parfitt" wrote:

"Telamon" wrote in message
...
In article vCsnf.20308$7r6.11890@trnddc07,
"Dale Parfitt" wrote:

"Telamon" wrote in message
.
..
In article Fnrnf.16004$hB6.15653@trnddc05,
"Dale Parfitt" wrote:

"Telamon" wrote in message

om.
..
In article ,
"Robert11" wrote:

Hello:

Lots of good info on loops from posts. Thanks all.

Just want to be sure re this:

When you talk about a Horiz Loop, you mean a true loop where
the end is connected back to the beginning.

Right ?

(not just a folded random length config with a free end)

Any possible advantages in not connecting it back ? (Interested
in broadband, omni coverage)

The answer to the first question is no. If you connect the ends
together you short the loop. The loop is a circular, triangular
or square shape with one opening in it. At this opening in the
loop you can directly connect coax cable lead-in to the radio so
the coax is connected across the loop gap.

The answer to the second question is no. If you do not connect
the other end to something then the loop is open and will behave
as a random length of wire or a wire antenna. This will pick up
signals and a lot of local noise. The loop connected across the
coax will have lower signal levels and in general will pick up
less local noise.

The loop wire routed horizontally will be fairly
omnidirectional.


As in my above post, an omni horizontal loop is a rarity and
occurs only over a very narrow BW. Don't confuse the fact that the
wire runs in 4 directions with making an omni. The resultant far
field pattern is a function of the vector currents in each wire-
they add and cancel resulting in patterns with a number of lobes
and a number of nulls, but not omni.

If the loop is electrically small then it will receive in the plane
of the loop, which in this case is horizontal and so will receive
omnidirectional.


The discussion I see is about running a wire loop with further
questions about whether the far end is connected or left open-direct
coax feed. Maybe I missed something- these would appear to be simple
wire loops- not electrically small loops I would associate with a
capacity tuned loop and/or loop preamps. Electrically small loops are
traditionally mounted vertically so the user can take advantage of
the nulling properties to reduce a local noise source.

I guesstimated an inside loop around the ceiling of a 10 foot square
room for example. This would be electrically small on the lower bands.
I've done the same with fairly good results.

--
Telamon
Ventura, California

By your definition, a 40' circumference loop ( 10X10) fails to meet the 1/10
wavelngth rule above 2.5MHz.

Maybe my choice of words was not the best. Electrically small antennas
does usually mean 1/10 or less wavelength.

Here 1 wavelength loop (MHz) = ~ 1005/feet.

To clarify, generally under a wavelength loops have visibility on edge
and at one wavelength or more into and out of the loop plane so a
horizontal loop would have visibility in its plane up to 25 MHz and
then tend to look up 25 MHz. At 25 MHz the loop would tend to look
omnidirectional.

You could argue that their would be horizontal directionality depending
on frequency under 25 MHz but SW tends not to be highly directional the
higher you go in frequency and at much lower frequency the loop looks
increasingly electrically small. The over all effect will be
omnidirectional at 25 MHz.

--
Telamon
Ventura, California