Dale Parfitt wrote:
Has anyone had a "bad", as in less then stellar performance, with a
Wellbrook ALA 1530
loop antenna?

Hi Terry,

I have a homebrew version of the Wellbrook shielded loop 7' in diameter. It
is in my woods on a short tower and rotator.
On 160M and 75M it is the same as my 80M inverted vee. It's a good performer
on MW/LW but not any real difference between it and a homebrew voltage probe
antenna with a 4' whip.

Loops are most useful where there is a single noise source that can be
nulled with the loop- other than that, it's a toss up.
There is still the wive's tale making the rounds that shielded loop are
immune to the E field noise - rubbish and well disproven in the literature.

So, in summary, I like mine for being a compact RX antenna for MW/LW, but at
least in my environment, not sure I would go to the trouble next time.

Dale W4OP
for PAR Electronics, Inc.

I am begining to think that many people over rate a loop because it has
lower over
all gain and therefore is quiter. Based on my experience with improved
detector and
audio chains I have come to understand that the signal to noise is the
only variable
that really matters. I wish my fancy HiFer beacon/test source had not
been fried
by Thor. Even the 13.xxMHz crsytal was toast! It would be interesting
to run some
real experiments to compare antennas the way I compared detectors and
post detection amplifiers.

BTW I have completly ripped out all of my coax and pulled down my
antennas.
Since I got rid of my desktop PC and I have gone to a laptop I found I
really needed
to redesign my radio desk. Since my antennas and coax have been up for
over 15
years, I decided to redo the whole mess.

Fall is a very good time to errect new antennas and I am going to
reroute all my coax
through 1/2" copper tubing that will be bonded to my perimeter ground
ring. An
electrician friend used his mini Ditch Witch to dig me a couple of
trenches. I hope
to have the antennas back up by Monday evening.

I typically research and build devcies in the summer, think about
antennas in teh
fall and do serious listening over the winter.

Terry

wrote in message
oups.com...

Dale Parfitt wrote:
Has anyone had a "bad", as in less then stellar performance, with a
Wellbrook ALA 1530
loop antenna?

Hi Terry,

I have a homebrew version of the Wellbrook shielded loop 7' in diameter.
It
is in my woods on a short tower and rotator.
On 160M and 75M it is the same as my 80M inverted vee. It's a good
performer
on MW/LW but not any real difference between it and a homebrew voltage
probe
antenna with a 4' whip.

Loops are most useful where there is a single noise source that can be
nulled with the loop- other than that, it's a toss up.
There is still the wive's tale making the rounds that shielded loop are
immune to the E field noise - rubbish and well disproven in the
literature.

So, in summary, I like mine for being a compact RX antenna for MW/LW,
but at
least in my environment, not sure I would go to the trouble next time.

Dale W4OP
for PAR Electronics, Inc.

I am begining to think that many people over rate a loop because it has
lower over
all gain and therefore is quiter. Based on my experience with improved
detector and
audio chains I have come to understand that the signal to noise is the
only variable
that really matters. I wish my fancy HiFer beacon/test source had not
been fried
by Thor. Even the 13.xxMHz crsytal was toast! It would be interesting
to run some
real experiments to compare antennas the way I compared detectors and
post detection amplifiers.

BTW I have completly ripped out all of my coax and pulled down my
antennas.
Since I got rid of my desktop PC and I have gone to a laptop I found I
really needed
to redesign my radio desk. Since my antennas and coax have been up for
over 15
years, I decided to redo the whole mess.

Fall is a very good time to errect new antennas and I am going to
reroute all my coax
through 1/2" copper tubing that will be bonded to my perimeter ground
ring. An
electrician friend used his mini Ditch Witch to dig me a couple of
trenches. I hope
to have the antennas back up by Monday evening.

I typically research and build devcies in the summer, think about
antennas in teh
fall and do serious listening over the winter.

Terry


I'll match your dipole against my 70m full-wave horizontal loop for equal
gain from 70M all they way up to 6M - can you say broadbanded? A dipole is
not.

Seeing-I-dawg wrote:
I'll match your dipole against my 70m full-wave horizontal loop for equal
gain from 70M all they way up to 6M - can you say broadbanded? A dipole is
not.

Can you rotate your "70M full-wave horizontal loop"?

And at 70M, or about 230 feet in "diameter", it is a very different
antenna
then a 1M much touted miracle loop. I don't think I was attempting to
compare
3' with 230'. One supposed advantage of the small, fractional
wavelength,
loop is the reported, or should I say reputed, highly directional
charactoristics.
That famous figure "8" pattern.

The dipole to which I am reffering is an amplified, very high IP3 and
IP2 unit with
very good,as in flat gain and very directional, from 100KHz to above
28MHz. I will
have to connect it to my scanner and see if I can receive any 6M ham
comms,
or more likely around here older 49MHz telephones. I suspect it will
run out of steam somewhere just above 35MHz, but I haven't checked. It
will be later next week before
I can do any tests as my "shack" is in pieces and I am reduced to a
DX398 coupled
to a ~50 random wire out the kitchen window.

Terry

wrote in message
oups.com...

Seeing-I-dawg wrote:
I'll match your dipole against my 70m full-wave horizontal loop for
equal
gain from 70M all they way up to 6M - can you say broadbanded? A dipole
is
not.

Can you rotate your "70M full-wave horizontal loop"?

No need to. It essentially receives equally well in all directions on all
bands, unlike a dipole.

And at 70M, or about 230 feet in "diameter", it is a very different
antenna
then a 1M much touted miracle loop.

No, the circumference is 70 meters = full wave horiz. loop @70M
If you were to transmit into this loop you would see a flat swr from 70M-6M.
No tuner required. Just need to match the ladder line to your tranmitter.
A dipole can't do that without a tuner.

I don't think I was attempting to
compare
3' with 230'. One supposed advantage of the small, fractional
wavelength,
loop is the reported, or should I say reputed, highly directional
charactoristics.
That famous figure "8" pattern.

The dipole to which I am reffering is an amplified, very high IP3 and
IP2 unit with
very good,as in flat gain and very directional, from 100KHz to above
28MHz.

A dipole, any dipole, is cut/tuned for a single band. Any signal outside
that band and its harmonics are attenuated.
Not so with a large loop - equal gain to dipoles at any frequency.

I will
have to connect it to my scanner and see if I can receive any 6M ham
comms,
or more likely around here older 49MHz telephones. I suspect it will
run out of steam somewhere just above 35MHz, but I haven't checked. It
will be later next week before
I can do any tests as my "shack" is in pieces and I am reduced to a
DX398 coupled
to a ~50 random wire out the kitchen window.

Terry


For your perusal:
http://www.cebik.com/wire/hl.html
http://www.cebik.com/fdim/atl1.html
http://www.cebik.com/wire/horloop.html

For your perusal:
http://www.cebik.com/wire/hl.html
http://www.cebik.com/fdim/atl1.html
http://www.cebik.com/wire/horloop.html



Here is a nice horiz loop program from
http://www.smeter.net/antennas/rjeloop4.php

"This program is self-contained and ready to use. It does not require
installation."
Click this link
http://www.smeter.net/software/rjeloop4.exe
then click Open to run from the web or Save to save the program to your hard
drive.

After you have entered the initial values you can vary the frequency up or
down. Then watch how the efficiancy and loss characteristics barely vary.

I'll match your dipole against my 70m full-wave horizontal loop for equal
gain from 70M all they way up to 6M - can you say broadbanded? A dipole is
not.

Apples and oranges. The current discussion is about electrically small,
rotatable loops.

Dale W4OP