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Old July 5th 07, 11:19 AM posted to sci.electronics.basics,rec.radio.amateur.antenna,alt.internet.wireless
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Posts: 182
Default AM Radio Receiver based on Spin Exchange Relaxation Free mechanism


"Radium" wrote in message
oups.com...
Hi:

Can the Spin Exchange Relaxation Free Magnetometer be used to receiver
distant AM radio signals in which the carrier frequency is 150 KHz?
What if the carrier frequency is 44.1 KHz [for the same reason CDs use
a 44.1 KHz sample rate]? 40 KHz?


Thanks a bunch,

Radium

Radium,

The simplest answer is no. The reason is that you specify 'distant'. The
strength of a magnetic field decays rapidly with distance and for most
practical purposes, 800 metres would be a maximum typical detection range
for man made magnetic fields as opposed to natural fields like the earth's
magnetic field. Man made fields can be many times thousands of times
stronger than the earth's magnetic field at a local level, but the field
strength decays rapidly as you move away from the source. A friends father
experimented with a factory machinery control system using induction coils a
foot long and about 8 inches in diameter wound with thousands of turns of
thin copper wire. The maximum reliable communication distance with this set
up was only 200 yards. This was 35+ years ago and detection techniques have
improved considerably. The reason for the experiment was to try and develop
a control system that could work in the presence of very high strength RF
fields. This was superceded by the development of fibre optic cabling which
was not susceptible to RF pickup.

Communication using the magnetic field element of electromagnetic waves is
best demonstrated by the 'molephone' devices used to communicate with cavers
underground. See the following link for details and try googling cave
rescue, underground communications, and molephone for more links.

http://www.scavalon.be/avalonuk/technical/radio1.htm

Squids and other highly sensitive magnetic field detectors can be used to
detect the most minute distortions or changes in the earths magnetic field
but are not suitable for communications use. It is possible to build a
magnetometer at home that is so sensitive that it will pick up disturbances
in the earth's magnetic field caused by solar activity for less than $100.
This is not however going to be capable of receiving and demodulating 150kHz
radio signals.

It doesn't really matter what frequencies you want to receive, 44kHz,
150kHz, 150MHz or what the modulation method is, a diode (or two) and a
tuned circuit are essentially at the heart of all receiving and demodulating
systems. They are cost effective, reasonably efficient and they work. Why
would you want to spend a million dollars to receive signals that can be
picked up (probably a lot better) on a ten dollar consumer radio?

Modulation methods, frequencies and bandwidths are chosen by commercial
broadcasters to meet specific demands, e.g. limited bandwidth available for
broadcasting, high fidelity music broadcasts, high efficiency powerful
signals that can punch through interference, etc, etc. The basic rule is to
get the job done as cheaply, efficiently and as quickly as possible.

Mike G0ULI


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Old July 6th 07, 02:07 AM posted to sci.electronics.basics,rec.radio.amateur.antenna,alt.internet.wireless
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First recorded activity by RadioBanter: May 2007
Posts: 78
Default AM Radio Receiver based on Spin Exchange Relaxation Free mechanism

On Jul 5, 3:19 am, "Mike Kaliski" wrote:
"Radium" wrote in message

oups.com... Hi:

Can the Spin Exchange Relaxation Free Magnetometer be used to receiver
distant AM radio signals in which the carrier frequency is 150 KHz?
What if the carrier frequency is 44.1 KHz [for the same reason CDs use
a 44.1 KHz sample rate]? 40 KHz?


Thanks a bunch,


Radium


Radium,

The simplest answer is no. The reason is that you specify 'distant'. The
strength of a magnetic field decays rapidly with distance and for most
practical purposes, 800 metres would be a maximum typical detection range
for man made magnetic fields as opposed to natural fields like the earth's
magnetic field. Man made fields can be many times thousands of times
stronger than the earth's magnetic field at a local level, but the field
strength decays rapidly as you move away from the source. A friends father
experimented with a factory machinery control system using induction coils a
foot long and about 8 inches in diameter wound with thousands of turns of
thin copper wire. The maximum reliable communication distance with this set
up was only 200 yards. This was 35+ years ago and detection techniques have
improved considerably. The reason for the experiment was to try and develop
a control system that could work in the presence of very high strength RF
fields. This was superceded by the development of fibre optic cabling which
was not susceptible to RF pickup.

Communication using the magnetic field element of electromagnetic waves is
best demonstrated by the 'molephone' devices used to communicate with cavers
underground. See the following link for details and try googling cave
rescue, underground communications, and molephone for more links.

http://www.scavalon.be/avalonuk/technical/radio1.htm

Squids and other highly sensitive magnetic field detectors can be used to
detect the most minute distortions or changes in the earths magnetic field
but are not suitable for communications use. It is possible to build a
magnetometer at home that is so sensitive that it will pick up disturbances
in the earth's magnetic field caused by solar activity for less than $100.
This is not however going to be capable of receiving and demodulating 150kHz
radio signals.

It doesn't really matter what frequencies you want to receive, 44kHz,
150kHz, 150MHz or what the modulation method is, a diode (or two) and a
tuned circuit are essentially at the heart of all receiving and demodulating
systems. They are cost effective, reasonably efficient and they work. Why
would you want to spend a million dollars to receive signals that can be
picked up (probably a lot better) on a ten dollar consumer radio?

Modulation methods, frequencies and bandwidths are chosen by commercial
broadcasters to meet specific demands, e.g. limited bandwidth available for
broadcasting, high fidelity music broadcasts, high efficiency powerful
signals that can punch through interference, etc, etc. The basic rule is to
get the job done as cheaply, efficiently and as quickly as possible.

Mike G0ULI


Radio waves are made up of electric and magnetic fields.

Couldn't the Spin Exchange Relaxation Free Magnetometer receive the
magnetic portions of AM radio waves at the carrier frequencies I
described? If not, why?

Agreed, static magnetic fields tend to decay rapidly as you move away
from them. However, alternating magnetic fields continue to propogate
by generating alternating electric fields of the same frequency. These
alternating electric fields, in turn, generate alternating magnetic
fields. The cycle keeps repeating.

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Old July 6th 07, 02:25 AM posted to sci.electronics.basics,rec.radio.amateur.antenna,alt.internet.wireless
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First recorded activity by RadioBanter: Jun 2006
Posts: 1,898
Default AM Radio Receiver based on Spin Exchange Relaxation Free mechanism

In rec.radio.amateur.antenna Radium wrote:

snip

Agreed, static magnetic fields tend to decay rapidly as you move away
from them. However, alternating magnetic fields continue to propogate
by generating alternating electric fields of the same frequency. These
alternating electric fields, in turn, generate alternating magnetic
fields. The cycle keeps repeating.


Nonsense as stated.

You have no understanding of the differences between:

1. A magnetic field
2. An electric field
3. An electromagnetic field.


--
Jim Pennino

Remove .spam.sux to reply.
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Old July 6th 07, 03:04 AM posted to sci.electronics.basics,rec.radio.amateur.antenna,alt.internet.wireless
DTC DTC is offline
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First recorded activity by RadioBanter: Jun 2007
Posts: 40
Default AM Radio Receiver based on Spin Exchange Relaxation Free mechanism

Radium wrote:
Couldn't the Spin Exchange Relaxation Free Magnetometer receive the
magnetic portions of AM radio waves at the carrier frequencies I
described? If not, why?

Agreed, static magnetic fields tend to decay rapidly as you move away
from them. However, alternating magnetic fields continue to propogate
by generating alternating electric fields of the same frequency. These
alternating electric fields, in turn, generate alternating magnetic
fields. The cycle keeps repeating.


This thread reminds me of situations where someone acquire a little
knowledge of something and extrapolates it into areas of which they have an
limited skill set for understanding them.

Also reminds me of explaining things to my mother...but we won't go there.

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Old July 6th 07, 06:25 AM posted to sci.electronics.basics,rec.radio.amateur.antenna,alt.internet.wireless
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First recorded activity by RadioBanter: Jun 2007
Posts: 1,336
Default AM Radio Receiver based on Spin Exchange Relaxation Free mechanism

Radium hath wroth:

Radio waves are made up of electric and magnetic fields.


Yep.

Couldn't the Spin Exchange Relaxation Free Magnetometer receive the
magnetic portions of AM radio waves at the carrier frequencies I
described? If not, why?


Nope.

1. The range of the magnetic field is limited. For example, you're
not going to bounce (errr... refract) a magnetic fields off the
ionosphere.

2. Magentometers use very big coils. Very big coils have lots of
inductance. Resonant circuits with lots of inductance tend to
resonate at very low frequencies. Figure on maybe 30Hz being the
highest frequency detectable by a magnetometer. Most roll off even
earlier to avoid 60Hz power line pickup.

3. Magnetometers are expensive. You're proposing using one as a
replacement for a 5 cent silicon diode detector. If the technology
doesn't get to you, the accountants will.

Agreed, static magnetic fields tend to decay rapidly as you move away
from them. However, alternating magnetic fields continue to propogate
by generating alternating electric fields of the same frequency. These
alternating electric fields, in turn, generate alternating magnetic
fields. The cycle keeps repeating.


Rubbish.
--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
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Old July 7th 07, 03:19 AM posted to sci.electronics.basics,rec.radio.amateur.antenna,alt.internet.wireless
art art is offline
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First recorded activity by RadioBanter: Sep 2006
Posts: 1,188
Default AM Radio Receiver based on Spin Exchange Relaxation Free mechanism

On 5 Jul, 22:25, Jeff Liebermann wrote:
Radium hath wroth:

Radio waves are made up of electric and magnetic fields.


Yep.

Couldn't the Spin Exchange Relaxation Free Magnetometer receive the
magnetic portions of AM radio waves at the carrier frequencies I
described? If not, why?


Nope.

1. The range of the magnetic field is limited. For example, you're
not going to bounce (errr... refract) a magnetic fields off the
ionosphere.

2. Magentometers use very big coils. Very big coils have lots of
inductance. Resonant circuits with lots of inductance tend to
resonate at very low frequencies. Figure on maybe 30Hz being the
highest frequency detectable by a magnetometer. Most roll off even
earlier to avoid 60Hz power line pickup.

3. Magnetometers are expensive. You're proposing using one as a
replacement for a 5 cent silicon diode detector. If the technology
doesn't get to you, the accountants will.

Agreed, static magnetic fields tend to decay rapidly as you move away
from them. However, alternating magnetic fields continue to propogate
by generating alternating electric fields of the same frequency. These
alternating electric fields, in turn, generate alternating magnetic
fields. The cycle keeps repeating.


Rubbish.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


I believe that the standard example of radiation referred to above
is in error.
I do not believe that radiation consists of fields of any sort
but consists of ejected static particles in form of a swarm.
I have asked the Eham forum to wade in on that one since it
appears they have more scientifically molecular inclined members.
The only cycle that repeates in radiation is the tank circuit of a
diagmagnetic material which is resonant i.e. equal capacitance and
inductance. Seems like the posts are relying on propagating fields
which to me is an error.
Regards
Art

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Old July 7th 07, 04:15 AM posted to sci.electronics.basics,rec.radio.amateur.antenna,alt.internet.wireless
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First recorded activity by RadioBanter: Jun 2006
Posts: 1,898
Default AM Radio Receiver based on Spin Exchange Relaxation Free mechanism

In rec.radio.amateur.antenna art wrote:
On 5 Jul, 22:25, Jeff Liebermann wrote:
Radium hath wroth:

Radio waves are made up of electric and magnetic fields.


Yep.

Couldn't the Spin Exchange Relaxation Free Magnetometer receive the
magnetic portions of AM radio waves at the carrier frequencies I
described? If not, why?


Nope.

1. The range of the magnetic field is limited. For example, you're
not going to bounce (errr... refract) a magnetic fields off the
ionosphere.

2. Magentometers use very big coils. Very big coils have lots of
inductance. Resonant circuits with lots of inductance tend to
resonate at very low frequencies. Figure on maybe 30Hz being the
highest frequency detectable by a magnetometer. Most roll off even
earlier to avoid 60Hz power line pickup.

3. Magnetometers are expensive. You're proposing using one as a
replacement for a 5 cent silicon diode detector. If the technology
doesn't get to you, the accountants will.

Agreed, static magnetic fields tend to decay rapidly as you move away
from them. However, alternating magnetic fields continue to propogate
by generating alternating electric fields of the same frequency. These
alternating electric fields, in turn, generate alternating magnetic
fields. The cycle keeps repeating.


Rubbish.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558


I believe that the standard example of radiation referred to above
is in error.


Belief doesn't make reality.

I do not believe that radiation consists of fields of any sort
but consists of ejected static particles in form of a swarm.


A hundred years or so of experments say that's utter, babbling,
nonsense.

I have asked the Eham forum to wade in on that one since it
appears they have more scientifically molecular inclined members.


Right.

The only cycle that repeates in radiation is the tank circuit of a
diagmagnetic material which is resonant i.e. equal capacitance and
inductance. Seems like the posts are relying on propagating fields
which to me is an error.


I'd suggest fluphenazine and haloperidol.


--
Jim Pennino

Remove .spam.sux to reply.
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Old July 7th 07, 04:36 AM posted to sci.electronics.basics,rec.radio.amateur.antenna,alt.internet.wireless
art art is offline
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First recorded activity by RadioBanter: Sep 2006
Posts: 1,188
Default AM Radio Receiver based on Spin Exchange Relaxation Free mechanism

On 6 Jul, 20:15, wrote:
In rec.radio.amateur.antenna art wrote:





On 5 Jul, 22:25, Jeff Liebermann wrote:
Radium hath wroth:


Radio waves are made up of electric and magnetic fields.


Yep.


Couldn't the Spin Exchange Relaxation Free Magnetometer receive the
magnetic portions of AM radio waves at the carrier frequencies I
described? If not, why?


Nope.


1. The range of the magnetic field is limited. For example, you're
not going to bounce (errr... refract) a magnetic fields off the
ionosphere.


2. Magentometers use very big coils. Very big coils have lots of
inductance. Resonant circuits with lots of inductance tend to
resonate at very low frequencies. Figure on maybe 30Hz being the
highest frequency detectable by a magnetometer. Most roll off even
earlier to avoid 60Hz power line pickup.


3. Magnetometers are expensive. You're proposing using one as a
replacement for a 5 cent silicon diode detector. If the technology
doesn't get to you, the accountants will.


Agreed, static magnetic fields tend to decay rapidly as you move away
from them. However, alternating magnetic fields continue to propogate
by generating alternating electric fields of the same frequency. These
alternating electric fields, in turn, generate alternating magnetic
fields. The cycle keeps repeating.


Rubbish.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

I believe that the standard example of radiation referred to above
is in error.


Belief doesn't make reality.

I do not believe that radiation consists of fields of any sort
but consists of ejected static particles in form of a swarm.


A hundred years or so of experments say that's utter, babbling,
nonsense.

I have asked the Eham forum to wade in on that one since it
appears they have more scientifically molecular inclined members.


Right.

The only cycle that repeates in radiation is the tank circuit of a
diagmagnetic material which is resonant i.e. equal capacitance and
inductance. Seems like the posts are relying on propagating fields
which to me is an error.


I'd suggest fluphenazine and haloperidol.

--
Jim Pennino

Remove .spam.sux to reply.- Hide quoted text -

- Show quoted text -


Jim, In the past you have shown that you are not that smart
and I see of no evidence of any change.
Suggest you review "particles" in nuclear physics,
tho I suppose some could see a swarm of particles as a "wave"
tho certainly not in the electrical sense.
Seems like you take comfort in harrassing people with
statements that have no reality. I have the strong suspicion
that you are also short in stature and thus have a macho
feeling in hiding. I personally have proved that radiation
is in particle form where you do not have the ability
to prove anything.



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