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.

Terry

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

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

In article .com,
"Ken Wilson" wrote:

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.

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

And this is the experience of most people with loop antennas.

Things are a bit more complicated with electrically small loop antennas
because amplifiers come into use. Now you have to consider amplifier
design along with antenna design to predict performance.

Larger loops require less amplification so the amplifier performance
becomes less of an issue.

Full size loop antennas are a little different dimensionally and
depending on your house lot you might be able to fit a loop on your lot
where you can't fit a full size dipole. This difference in dimensions
may allow you get the full size loop farther away from a local noise
source.

--
Telamon
Ventura, California

In article oZuTg.1266$753.664@trnddc05,
"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.

I'm sure he is a great guy and knows a lot but that does not mean he is
right. What he states is against theory and experience. I will go with
what practical experience supported by theory over someone's preeminent
opinion.

His opinion is contrary to the theory of operation of electrically small
shielded (or unshielded for that matter) loops compared to electric
field probes (example single wire or dipole).

You possibly misconstrued what you read in the IEEE journal.

We just had a discussion about inductive noise probes for trouble
shooting problems. Maybe you missed that. It was discussed here about
using a small shielded loop to distinguish between magnetic fields and a
short wire probe to pick up electric fields. Now this past discussion
relates to very close local induction fields. This is the very situation
the author you refer to claims the shielded loop probe would be useless
as it would be no different than the voltage probe response. Well sorry,
these probes really work as advertised because I used them
professionally and successfully.

My experience building and using antennas also run contrary to what the
author you refer to states. My experience in antenna building is also
predicted by theory. Most other people have had similar experiences
using loop and dipole antennas.

Again I will mention that there is a difference between an inductive
field and a far field that is a propagating wave and that theoretically
there will be a significant difference in response between E and H field
sensitive antennas to the inductive but not the far field.

--
Telamon
Ventura, California