On Thu, 22 Jan 2009 01:06:28 -0000, "christofire"
wrote:

With a pair of screened loops and a whip it is possible to receive
separately the magnetic and electric fields associated with a radio signal
and to record their strengths at different locations. This can reveal
significant differences on account of building and electrical clutter, but
only if the loop is adequately screened. No myth!

What you describe is a direction finding system with a general antenna
that can be switched in to sniff for a transmitter to take a bearing
on. A commonplace design for this application. The loops are no more
screened than any other, and careful observation of their construction
details would reveal the necessary break in the screen which serves
for balance only. Any claims to magnetic field separation are, as
Mark well put it, a myth.

The only way you could achieve this separation is by traveling at the
speed of light with your antenna in that magnetic field, at its 90
degree peak to the electric field null. This reduces the topic from
the status of myth to that of absurd.

73's
Richard Clark, KB7QHC

On Jan 21, 3:11*pm, Cecil Moore wrote:
wrote:
The way I look at it, there is no such thing as a "magnetic" antenna.

Given that a transmitting dipole and a receiving dipole
transfer maximum signal when oriented in the same plane,
how does one explain a ferrite loop antenna receiving
maximum signal in a plane orthogonal to the transmitting
dipole?
--
73, Cecil *http://www.w5dxp.com

I'm not sure without looking into it, but I notice this with
both shielded, and unshielded loops.
As an example, my 44 inch per side 5 turn diamond
loop prefers to be fed horizontally vs vertically
when receiving MW stations which use a vertical
transmit antenna.
IE: I feed it at the middle lowest corner.
If I feed it at a side corner, which would be vertically fed,
I seem to remember it not working near as well.
Do you consider an open small loop "unshielded" a
"magnetic" antenna? Some do, but I tend not to.
They act the same as the shielded loops that many
seem to call "magnetic" antennas.
The ability to respond to mostly the magnetic field
vs the electric field only pertains to the very near field
within about 1/10 wavelength.
Within 1 wavelength they often respond more to the
electrical wave. In the far field they should respond
to both fields the same as any other antenna.
Or this is my current understanding anyway.. :/
So using any type of "magnetic" antenna for the OP's
purpose would seem to be a waste of time unless
they are trying to reduce noise pickup that is within
1/10 of a wavelength away.
I know myself that these small loops are still quite
capable of picking up local noise, just like most
any other antenna. The only advantage are the sharp
nulls which you use to get rid of said noise.
If your mobile tests were within 1/10 of a wave,
maybe it makes more sense. But I'm not sure if
I can see any advantage to trying to receive a far
field signal vs any other antenna unless the nulls
are useful.

On Wed, 21 Jan 2009 17:46:36 -0800 (PST), wrote:

IE: I feed it at the middle lowest corner.
If I feed it at a side corner, which would be vertically fed,
I seem to remember it not working near as well.

Hi Mark,

That would seem to indicate you seriously unbalanced the antenna by
the side feed which is geometrically unbalanced. For instance, the
line doesn't lead off horizontally for any great distance, does it?

Of course, this all hinges on what you mean by not "near as well."

73's
Richard Clark, KB7QHC

"Richard Clark" wrote in message
...
On Thu, 22 Jan 2009 01:06:28 -0000, "christofire"
wrote:

With a pair of screened loops and a whip it is possible to receive
separately the magnetic and electric fields associated with a radio signal
and to record their strengths at different locations. This can reveal
significant differences on account of building and electrical clutter, but
only if the loop is adequately screened. No myth!

What you describe is a direction finding system with a general antenna
that can be switched in to sniff for a transmitter to take a bearing
on. A commonplace design for this application.

No, the loops were commutated in order to provide an omni-direction pattern
in the horizontal plane and the receiver was switched between the loops and
whip to measure H and E. This was used to establish for medium and
long-wave broadcasting stations (in the UK) the field strength and
receivability on ferrite-rod antennas.

The loops are no more
screened than any other, and careful observation of their construction
details would reveal the necessary break in the screen which serves
for balance only.

The loop has to be split at some point to prevent it acting as a shorted
turn - the splits were at the top in this case.

Any claims to magnetic field separation are, as
Mark well put it, a myth.

The only way you could achieve this separation is by traveling at the
speed of light with your antenna in that magnetic field, at its 90
degree peak to the electric field null.

In a normal single, plane-polarised, far-field TEM radio wave the peaks of E
and H occur at the same places and the same times, and the nulls of E and H
occur at the same places and the same times. The peaks of both correspond
to the peaks of current in the transmitting antenna by which they were
generated, and the nulls of both correspond to the zero-crossings of the
current. If you believe something is radiated in the far field when the
current in the antenna is zero I would be intrigued to hear an explanation.

This reduces the topic from
the status of myth to that of absurd.

You're entitled to your opinion.

Chris


73's
Richard Clark, KB7QHC

wrote:
On Jan 21, 3:11 pm, Cecil Moore wrote:
Given that a transmitting dipole and a receiving dipole
transfer maximum signal when oriented in the same plane,
how does one explain a ferrite loop antenna receiving
maximum signal in a plane orthogonal to the transmitting
dipole?

I'm not sure without looking into it, but I notice this with
both shielded, and unshielded loops.

I'm not talking about coaxial loops. I'm talking about
coils of wire wrapped around a ferrite rod typical of
AM radios. Seems pretty obvious it is responding to the
magnetic field when it needs to be at right angles to
the transmitting monopole (or dipole).
--
73, Cecil http://www.w5dxp.com

On Thu, 22 Jan 2009 10:19:14 -0000, "christofire"
wrote:


"Richard Clark" wrote in message
.. .
On Thu, 22 Jan 2009 01:06:28 -0000, "christofire"
wrote:

With a pair of screened loops and a whip it is possible to receive
separately the magnetic and electric fields associated with a radio signal
and to record their strengths at different locations. This can reveal
significant differences on account of building and electrical clutter, but
only if the loop is adequately screened. No myth!

What you describe is a direction finding system with a general antenna
that can be switched in to sniff for a transmitter to take a bearing
on. A commonplace design for this application.

No, the loops were commutated in order to provide an omni-direction pattern
in the horizontal plane and the receiver was switched between the loops and
whip to measure H and E. This was used to establish for medium and
long-wave broadcasting stations (in the UK) the field strength and
receivability on ferrite-rod antennas.

The description you offer in rebuttal says nothing of field
separation. The commutation discussion imparts nothing to the
physical relationship of the wave. The remainder of the description
doesn't actually describe any physical/geometric relationship to the
wave at all. Physics in the UK are not different from the rest of the
world.

The loops are no more
screened than any other, and careful observation of their construction
details would reveal the necessary break in the screen which serves
for balance only.

The loop has to be split at some point to prevent it acting as a shorted
turn - the splits were at the top in this case.

This, too, is merely conventional design then.

You haven't described anything out of the ordinary, and the ordinary
(spanning centuries) has not shown the attributes you describe as
field separation.

You're entitled to your opinion.

As are you, but this isn't rec.radio.amateur.antenna.polls and you
haven't gone beyond unsubstantiated claims.

If the necessity of proof for your claims were set aside, Nature still
demands that noise and signal still arrive by the same mechanism and
any invention that separates fields must apply them equally to both
sources - returning us to the conventional observation that S/N hasn't
changed one bit. The net result of this is that you have provided
unsubstantiated claims for an useless invention. Any value it may
have comes by conventional means.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On Thu, 22 Jan 2009 10:19:14 -0000, "christofire"
wrote:

"Richard Clark" wrote in message
...
On Thu, 22 Jan 2009 01:06:28 -0000, "christofire"
wrote:

With a pair of screened loops and a whip it is possible to receive
separately the magnetic and electric fields associated with a radio signal
and to record their strengths at different locations. This can reveal
significant differences on account of building and electrical clutter, but
only if the loop is adequately screened. No myth!
What you describe is a direction finding system with a general antenna
that can be switched in to sniff for a transmitter to take a bearing
on. A commonplace design for this application.
No, the loops were commutated in order to provide an omni-direction pattern
in the horizontal plane and the receiver was switched between the loops and
whip to measure H and E. This was used to establish for medium and
long-wave broadcasting stations (in the UK) the field strength and
receivability on ferrite-rod antennas.

The description you offer in rebuttal says nothing of field
separation. The commutation discussion imparts nothing to the
physical relationship of the wave. The remainder of the description
doesn't actually describe any physical/geometric relationship to the
wave at all. Physics in the UK are not different from the rest of the
world.

The loops are no more
screened than any other, and careful observation of their construction
details would reveal the necessary break in the screen which serves
for balance only.
The loop has to be split at some point to prevent it acting as a shorted
turn - the splits were at the top in this case.

This, too, is merely conventional design then.

You haven't described anything out of the ordinary, and the ordinary
(spanning centuries) has not shown the attributes you describe as
field separation.

You're entitled to your opinion.

As are you, but this isn't rec.radio.amateur.antenna.polls and you
haven't gone beyond unsubstantiated claims.

If the necessity of proof for your claims were set aside, Nature still
demands that noise and signal still arrive by the same mechanism and
any invention that separates fields must apply them equally to both
sources - returning us to the conventional observation that S/N hasn't
changed one bit. The net result of this is that you have provided
unsubstantiated claims for an useless invention. Any value it may
have comes by conventional means.

73's
Richard Clark, KB7QHC

Hi Richard,

Are your powers of perception waning by any chance? Your correspondent
deserves more credit than you're allowing him. As far as I've seen in
this thread, you're the only one talking about 'field delamination' or
such things. As you said, what he is talking about is purely
conventional. And clever. That you apparently don't completely
understand what he is saying is no fault of his.

73, ac6xg

On Thu, 22 Jan 2009 11:18:03 -0800, Jim Kelley
wrote:

Are your powers of perception waning by any chance? Your correspondent
deserves more credit than you're allowing him. As far as I've seen in
this thread, you're the only one talking about 'field delamination' or
such things.

Perhaps you powers of perception did not perceive this:
On Thu, 22 Jan 2009 01:06:28 -0000, "christofire" wrote:

With a pair of screened loops and a whip it is possible to receive
separately the magnetic and electric fields associated with a radio signal

Returning to your complaint:
That you apparently don't completely
understand what he is saying is no fault of his.

As christofire's quote above is his and not mine, and neither you nor
he has explained it, my comprehension is not tested beyond what his
unconventional statement has offered. If he cannot explain it, then
the fault is not with me. Challenging blank assertions is not unusual
here.

Perhaps you mis-perceived:
On Thu, 22 Jan 2009 01:06:28 -0000, "christofire" wrote:

The way I look at it, there is no such thing as a "magnetic" antenna.
because, in fact due to christofire's poor quotation practice, this
statement is Mark's and one that I fully concur with and stated so.

73's
Richard Clark, KB7QHC

Richard Clark wrote:
On Thu, 22 Jan 2009 11:18:03 -0800, Jim Kelley
wrote:

Are your powers of perception waning by any chance? Your correspondent
deserves more credit than you're allowing him. As far as I've seen in
this thread, you're the only one talking about 'field delamination' or
such things.

Perhaps you powers of perception did not perceive this:
On Thu, 22 Jan 2009 01:06:28 -0000, "christofire" wrote:

With a pair of screened loops and a whip it is possible to receive
separately the magnetic and electric fields associated with a radio signal

I perceive that the quote says nothing about "field separation" -
whatever that is. Since it's a term that you employed, perhaps you can
explain what you mean by it and clear up the whole thing.

Thanks,

ac6xg

On Thu, 22 Jan 2009 13:43:19 -0800, Jim Kelley
wrote:

separately the magnetic and electric fields associated with a radio signal

I perceive that the quote says nothing about "field separation" -

Now that is getting "précis."

73's
Richard Clark, KB7QHC