In article om,
wrote:

Steve wrote:


One thing you might do is check the cables connecting the different
components of the Wellbrook. At one point I noticed that my loop
wasn't performing as I thought it should and I discovered that the
cable connecting the receiver to the antenna interface had a poor
connection where it meets the interface box. The intermittent
connection became obvious as soon as I jiggled the cable a bit.

Also, where do you have the loop situated? In my experience the
performance of the loop is seriously degraded when used indoors.

Calbe and connectors are good, and have been used to power the
Lankford active dipole I am checking.

I have tried it in a variety of locations.

We even went so far as to drive to the Red River Gorge, an area well
away from houses, power lines etc.

The preformance just doesn't strike me as being worth the fairly high
cost.

The active dipole beat it every time.

That was a self defeating test. The idea here is that you will have a
lower noise floor in a locally noisy area with a shielded loop than a
dipole antenna. There is going to be no advantage to using a loop over
a dipole in an electrically quiet area.

A shielded loop is not better at picking up a distant signal than a
dipole but is less sensitive to local noise generators so in an area
with high local noise you would have better signal to noise than a
full size dipole antenna.

I also expect that a shielded loop would be better than a amplified
electrically small dipole although the difference in advantage would be
smaller than the comparison to a full sized dipole. Depending on the
area a electrically small dipole and shielded loop may not have a
significant difference in local noise floor because you managed to get
both far enough from local noise makers due to their small size.

If you found a problem connection from interface to antenna then I
would suspect your findings. As you well know that connection is the
power supply to the antenna amplifier and the RF path back to the
radio.

"The active dipole beat it every time" is a bit vague. Maybe you could
expand a little on that.

--
Telamon
Ventura, California

" That was a self defeating test. The idea here is that you will have a
lower noise floor in a locally noisy area with a shielded loop than a
dipole antenna. There is going to be no advantage to using a loop over
a dipole in an electrically quiet area.

A shielded loop is not better at picking up a distant signal than a
dipole but is less sensitive to local noise generators so in an area
with high local noise you would have better signal to noise than a
full size dipole antenna.

Please see:
http://www.w8ji.com/magnetic_receiving_loops.htm

Dale W4OP

In article kImTg.111$pS3.23@trnddc01,
"Dale Parfitt" wrote:

" That was a self defeating test. The idea here is that you will have a
lower noise floor in a locally noisy area with a shielded loop than a
dipole antenna. There is going to be no advantage to using a loop over
a dipole in an electrically quiet area.

A shielded loop is not better at picking up a distant signal than a
dipole but is less sensitive to local noise generators so in an area
with high local noise you would have better signal to noise than a
full size dipole antenna.

Please see:
http://www.w8ji.com/magnetic_receiving_loops.htm

A nice page written by some amateur drawing wrong conclusions. Following
his logic coax cable would not shield the center conductor either for
example since the coax has to be open on both ends. He quotes a lot of
good information and then spouts conclusion that don't follow.

I don't have the patience to read the whole page but I scanned through
it and for starters he does not seem to distinguish between far and near
field energy. Far field has equal energy in the E and H fields so two
antennas, example dipole and loop, that are strongly couple to one field
and not the other generate the same power. No real difference then
between antennas that are strongly affected by one field and not the
other to far field signal or noise.

Near field is a different story. Near field is what the local noise
makers generate the most of and the electric tends to propagate farther
than the magnetic from the source so you want to use an antenna that is
sensitive to the H field for the same reason you try to get an antenna
as far away from local noise sources as possible. You can see the logic
in that right?

And let's not forget about that very handy null in the loop pattern. I
use that all the time on the AM portable with its built in loop stick
antenna that is not even shielded.

--
Telamon
Ventura, California

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

Given the almost sacred refference the Wellbrook is held in I have
debated asking
this question. I have a ALA 1530 that is part of a trade that I am
looking at and
guys I just don't get it. This antenna is reputed to be the cat's meow,
but I have
found it marginal at best. A north country active antenna is nearly
it's match
and the 3rd harmonic of a local MW (770KHz) is S3 on the Wellbrook. A
Lankford Active Dipole stomps it in gain, IP2 and IP3 and for
directivity.

I am wondering if this antenna is defective or if it is a case of the
Emperors New
Clothes. I have tried loops several times in the last 30 years and
always give up
becuase I have never found the reported imunity against local QRM to be
true.
I am building a copy of the WL1030 (http://wl1030.com/), but I don't
understand
the fascination with loops. What am I missing?

For MW DX "big" air loops make sense. Good directivity to null out an
offending
signal. I notice Ron Harding uses McKay 100E with a phaser to achieve
good
nulls. For HF the sky wave "smears" both the desired and unwanted
signals
making a null very iffy.

Receivers used in this test:
R2000
R8B
R390
R392
The R390 and R392 where not tested at my home but at a friend's home
where I have them stored. While I like both the R390 and R392, they are
somewhat awkward to rapidly tune from one frequency to a wildly
seperated
one.

Terry

I use the ALA 100. The smaller loops may not be as good on MW. It is a
good idea to insure the amplifer is actually doing something. The fuse
could be blown, the wall wart bad, etc. Unplug the power connector and
make sure the signal strength drops. You will get reception from the
loop even if the amp is off since some RF will leak.

Some of the Wellbrook amps were positive ground. The unit is fused and
I would guess there is a reverse biased protection diode. If the wrong
wall wart was used, it would pop the fuse. In my portable set up, I
have red shrink wrap on the connector that goes to the Wellbrook, just
to make it clear the ground is backwards.

As far as the 1530 goes, it may not have a good resale value since they
released the "plus" version, which has response in the FM BCB.

wrote:


I use the ALA 100. The smaller loops may not be as good on MW. It is a
good idea to insure the amplifer is actually doing something. The fuse
could be blown, the wall wart bad, etc. Unplug the power connector and
make sure the signal strength drops. You will get reception from the
loop even if the amp is off since some RF will leak.

Some of the Wellbrook amps were positive ground. The unit is fused and
I would guess there is a reverse biased protection diode. If the wrong
wall wart was used, it would pop the fuse. In my portable set up, I
have red shrink wrap on the connector that goes to the Wellbrook, just
to make it clear the ground is backwards.

As far as the 1530 goes, it may not have a good resale value since they
released the "plus" version, which has response in the FM BCB.

Checking that fuse is a very good idea. I once blew mine by accident
when a piece of coax I was using turned out to have a short. I didn't
immediately realize what had happened and went a few days simply
thinking that conditions were terrible. LOL.

Steve

wrote:

I use the ALA 100. The smaller loops may not be as good on MW. It is a
good idea to insure the amplifer is actually doing something. The fuse
could be blown, the wall wart bad, etc. Unplug the power connector and
make sure the signal strength drops. You will get reception from the
loop even if the amp is off since some RF will leak.

Some of the Wellbrook amps were positive ground. The unit is fused and
I would guess there is a reverse biased protection diode. If the wrong
wall wart was used, it would pop the fuse. In my portable set up, I
have red shrink wrap on the connector that goes to the Wellbrook, just
to make it clear the ground is backwards.

As far as the 1530 goes, it may not have a good resale value since they
released the "plus" version, which has response in the FM BCB.

This ALA 1530 requires a reversed, is shell positve and inner negative,
wall wart. But the center conductor of the coax was positive. I left
the
original power injector/diplexer intact and built my own. I verified
the
problem with the stock wall wart/diplexer before trying my own.

With out power I get virtually no signals. A few very strong MW and SW
at way less then S1. So the amp is working. The original owner says
it always behaved like this. OK, but clearly not the do all end all
of antennas.

Terry

A nice page written by some amateur drawing wrong conclusions. Following
his logic coax cable would not shield the center conductor either for
example since the coax has to be open on both ends. He quotes a lot of
good information and then spouts conclusion that don't follow.

The author of the page is one of the most respected amateurs, an active
consulting engineer, designer of the DX engineering Low band line of active
antennas, and widely published. I have read identical conclusions in the
IEEE Journal on EM.

The null of the loop is its best feature. We agree there.

Dale W4OP

Very interesting post's on this subject so far. Sure is nice to have
some topics that are about DX & radios.

I did a bunch of CW contesting back some years ago & am very familiar
with W8JI's station. All of the best ops in the country wanted to run
his station during the ARRL 160 cw contest. BIG signal & could work
stations most could not even hear.

My point is I am sure he "knows his stuff".

With that said....I have 2 hf antennas up right now. A wellbrook K9AY &
a wellbrook ALA 1530. The 1530 is mounted at 6ft off the ground
strapped to a wooden fence.

The K9AY always has a signal that shows more s-units. However many
times the 1530 will give a better s/n ratio.

It took me a while to "get over" the lower s meter reading & realize I
was hearing the signal better because of the better s/n ratio.

My location is in a housing project with several houses within 300 ft
of me so the loss in gain was not hurting me since my noise floor was
higher.

Now If I were located out in the wide open spaces with no man made
noise for miles then the 1530 would have no where near enough gain.

All of these are my opinions of course


Ken KG4BIG


Dale Parfitt wrote:
A nice page written by some amateur drawing wrong conclusions. Following
his logic coax cable would not shield the center conductor either for
example since the coax has to be open on both ends. He quotes a lot of
good information and then spouts conclusion that don't follow.

The author of the page is one of the most respected amateurs, an active
consulting engineer, designer of the DX engineering Low band line of active
antennas, and widely published. I have read identical conclusions in the
IEEE Journal on EM.

The null of the loop is its best feature. We agree there.

Dale W4OP

Ken Wilson wrote:
Very interesting post's on this subject so far. Sure is nice to have
some topics that are about DX & radios.

I did a bunch of CW contesting back some years ago & am very familiar
with W8JI's station. All of the best ops in the country wanted to run
his station during the ARRL 160 cw contest. BIG signal & could work
stations most could not even hear.

My point is I am sure he "knows his stuff".

With that said....I have 2 hf antennas up right now. A wellbrook K9AY &
a wellbrook ALA 1530. The 1530 is mounted at 6ft off the ground
strapped to a wooden fence.

The K9AY always has a signal that shows more s-units. However many
times the 1530 will give a better s/n ratio.

It took me a while to "get over" the lower s meter reading & realize I
was hearing the signal better because of the better s/n ratio.

My location is in a housing project with several houses within 300 ft
of me so the loss in gain was not hurting me since my noise floor was
higher.

Now If I were located out in the wide open spaces with no man made
noise for miles then the 1530 would have no where near enough gain.

All of these are my opinions of course


Ken KG4BIGY


Perhaps my local noise floor is "good enough" that whatever benifit the
Wellbrook offers is lost. I am trading the newly aquired ALA 1530 to
an acquaintance who lives in downtown Lexington for a Datong
AD370 that was only used for a few weeks.

He is aware of my doubts about the ALA1530's ability but says he has
nothing to loose. When I get a copy of the WL1030 built we will test it
at his condo.

Terry

Ken Wilson wrote:
Very interesting post's on this subject so far. Sure is nice to have
some topics that are about DX & radios.

I did a bunch of CW contesting back some years ago & am very familiar
with W8JI's station. All of the best ops in the country wanted to run
his station during the ARRL 160 cw contest. BIG signal & could work
stations most could not even hear.

My point is I am sure he "knows his stuff".

With that said....I have 2 hf antennas up right now. A wellbrook K9AY &
a wellbrook ALA 1530. The 1530 is mounted at 6ft off the ground
strapped to a wooden fence.

The K9AY always has a signal that shows more s-units. However many
times the 1530 will give a better s/n ratio.

It took me a while to "get over" the lower s meter reading & realize I
was hearing the signal better because of the better s/n ratio.

My location is in a housing project with several houses within 300 ft
of me so the loss in gain was not hurting me since my noise floor was
higher.

Now If I were located out in the wide open spaces with no man made
noise for miles then the 1530 would have no where near enough gain.

All of these are my opinions of course


Ken KG4BIG


Dale Parfitt wrote:
A nice page written by some amateur drawing wrong conclusions. Following
his logic coax cable would not shield the center conductor either for
example since the coax has to be open on both ends. He quotes a lot of
good information and then spouts conclusion that don't follow.

The author of the page is one of the most respected amateurs, an active
consulting engineer, designer of the DX engineering Low band line of active
antennas, and widely published. I have read identical conclusions in the
IEEE Journal on EM.

The null of the loop is its best feature. We agree there.

Dale W4OP

Thanks to all for the most interesting and relevant thread on this group
I can remember. I have a North County antenna in an apartment community
and hope someday to have a way and means to install Dale's antenna but
right now The North County will hafta' do, and I am amazed how well it
works here in central Florida

Yodar w/RX 320