The loops respond to the magnetic portion of the wave, while most noise
is electrical.

In most loop applications, they are much shorter than a wavelength. At
least for shortwave.


Dale Parfitt wrote:
"Robert11" wrote in message
...
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)

Thanks,
Bob
There are very few configurations in which a horizontal loop offers a
quasi omni pattern- the one exception I can think of is when the loop is in
the vicinity of a half wavelength and the far ends are close. but not
touching- even here the pattern is not omni but elliptical in azimuth.
A 1 wavelength loop has a pattern nearly identical to a half wave dipole-
i.e. figure 8, slightly less gain than the dipole, and narrower bandwidth.

At other lengths, the loop, like a center fed wire, will devleop multiple
nulls. Of course, like the dipole at low heights, the nulls tend to fill in.

IMHO, I fail to understand the fascination with the loop configuration. If
it is a "quieter" antenna than a dipole ( and I can see no reason for this
other than the idea that it is a DC short) then a dipole could be made
equally quiet by placing a suitable choke across the center insulator.

Take off angle is identical to a dipole at the same height.
Dale W4OP

wrote in message
oups.com...
The loops respond to the magnetic portion of the wave, while most noise
is electrical.

In most loop applications, they are much shorter than a wavelength. At
least for shortwave.
I reread the original post and am convinced the poster is referring to a
horizontal wire loop of large dimanesions- i.e. not fractional wavelength.
I personally have a homebrew 7' shielded loop with wideband preamp on a
short tower some 200' from my home- if the noise source is not in the near
field, these antennas have no noise advantage except in the null directions.
See:
http://www.w8ji.com/magnetic_receiving_loops.htm

Dale W4OP

Hmmh, 200ft from my house would be in my neighbor's neighbor's yard. If
you live in an urban environment, you appreciate the low noise. I have
at least two street lights within 200ft, and probably 4 if I bothered
to research it. Those buggers are really noisy.

When I finally gave up the long wire, it was after using a seriously
long wire (about 100ft) in a very remote area, and compared it to 40ft
on the Wellbrook ALA100. The Wellbrook kicked ass every time. I've
been fiddling with multiple turns with the ALA100, and finally have
some local BCB stations forcing the atennuator to turn on.


Dale Parfitt wrote:
wrote in message
oups.com...
The loops respond to the magnetic portion of the wave, while most noise
is electrical.

In most loop applications, they are much shorter than a wavelength. At
least for shortwave.
I reread the original post and am convinced the poster is referring to a
horizontal wire loop of large dimanesions- i.e. not fractional wavelength.
I personally have a homebrew 7' shielded loop with wideband preamp on a
short tower some 200' from my home- if the noise source is not in the near
field, these antennas have no noise advantage except in the null directions.
See:
http://www.w8ji.com/magnetic_receiving_loops.htm

Dale W4OP

Hmmh, 200ft from my house would be in my neighbor's neighbor's yard. If
you live in an urban environment, you appreciate the low noise. I have
at least two street lights within 200ft, and probably 4 if I bothered
to research it. Those buggers are really noisy....................

Changing antenna types will not reduce the pickup of that noise,
unless there are nulls in those directions.

When I finally gave up the long wire, it was after using a seriously
long wire (about 100ft) in a very remote area, and compared it to 40ft
on the Wellbrook ALA100. The Wellbrook kicked ass every time. I've
been fiddling with multiple turns with the ALA100, and finally have
some local BCB stations forcing the atennuator to turn on.

Well sure...The small loop, "I assume that is what the wellbrook is",
has good nulls. You are comparing apples to grapefruit. Has nothing
to do with the *fictional* noise reducing qualities of the loops. Has
to
do with the nulls. If you have two wire antennas, and one is quieter
in a certain direction that another, it's the inferior antenna. Noise
is
RF, same as the desired signal you are trying to pick up. If you
reduce noise in a certain direction, you will also reduce the level
of any desired signals in that direction.
MK

There is one of them sodium vapor (or whatever it is) street lights up
there on that pole at the edge of my driveway.I often think about
shooting that d..n light out.Stupid d..n big a.. transformer is hangin
up on that Stupid wooden pole too.All kinds of s..t is up there too.I
fell asleep on my doggys couch last night,(beer) (she didn't care) and
when I woked up this morning,it was about an hour later that I noticed
my top plate plastic teeth had fell out.
cuhulin

In article .com,
wrote:
MK

MK, will you learn to quote the previous poster's text properly?

Those "" or ":" or whatever are there for a reason. By not
diffentiating your comments from the previous text, it makes
your postings not worth the time to takes to decipher who said
what.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)

Nulls aren't significant unless there are interfering signal to be
nulled out. In my test, this was not the case. I simply compared the
quality of the signals, and the Wellbrook was the winner


wrote:
Hmmh, 200ft from my house would be in my neighbor's neighbor's yard. If
you live in an urban environment, you appreciate the low noise. I have
at least two street lights within 200ft, and probably 4 if I bothered
to research it. Those buggers are really noisy....................

Changing antenna types will not reduce the pickup of that noise,
unless there are nulls in those directions.

When I finally gave up the long wire, it was after using a seriously
long wire (about 100ft) in a very remote area, and compared it to 40ft
on the Wellbrook ALA100. The Wellbrook kicked ass every time. I've
been fiddling with multiple turns with the ALA100, and finally have
some local BCB stations forcing the atennuator to turn on.

Well sure...The small loop, "I assume that is what the wellbrook is",
has good nulls. You are comparing apples to grapefruit. Has nothing
to do with the *fictional* noise reducing qualities of the loops. Has
to
do with the nulls. If you have two wire antennas, and one is quieter
in a certain direction that another, it's the inferior antenna. Noise
is
RF, same as the desired signal you are trying to pick up. If you
reduce noise in a certain direction, you will also reduce the level
of any desired signals in that direction.
MK

Which Wellbrook antenna do you have?
How high is it?
....and what radio do you have?



wrote in message
oups.com...
Nulls aren't significant unless there are interfering signal to be
nulled out. In my test, this was not the case. I simply compared the
quality of the signals, and the Wellbrook was the winner


wrote:
Hmmh, 200ft from my house would be in my neighbor's neighbor's yard. If
you live in an urban environment, you appreciate the low noise. I have
at least two street lights within 200ft, and probably 4 if I bothered
to research it. Those buggers are really noisy....................

Changing antenna types will not reduce the pickup of that noise,
unless there are nulls in those directions.

When I finally gave up the long wire, it was after using a seriously
long wire (about 100ft) in a very remote area, and compared it to 40ft
on the Wellbrook ALA100. The Wellbrook kicked ass every time. I've
been fiddling with multiple turns with the ALA100, and finally have
some local BCB stations forcing the atennuator to turn on.

Well sure...The small loop, "I assume that is what the wellbrook is",
has good nulls. You are comparing apples to grapefruit. Has nothing
to do with the *fictional* noise reducing qualities of the loops. Has
to
do with the nulls. If you have two wire antennas, and one is quieter
in a certain direction that another, it's the inferior antenna. Noise
is
RF, same as the desired signal you are trying to pick up. If you
reduce noise in a certain direction, you will also reduce the level
of any desired signals in that direction.
MK