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

On Jul 4, 8:44 pm, Radium wrote:
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,

Please note that 150 kHz, 44.1 kHz and 40 kHz
are technically not in the High Frequency (HF)
Spectrum and can not be called Shortwaves
http://en.wikipedia.org/wiki/High_frequency
http://en.wikipedia.org/wiki/Shortwave

-REMOVE- This Cross-Posted Message from
the "Rec.Radio.Shortwave" Newgroup.

Responders - Please Do Not Post Any Replies
to the the "Rec.Radio.Shortwave" Newgroup.
- - - Put A Check On Your Cross Posting Please.

tyvm ~ RHF

On Jul 4, 8:44 pm, Radium wrote:
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


OOPS! Totally forget bout da link!

http://72.14.253.104/search?q=cache:...&gl=us&strip=1

On Jul 4, 9:41 pm, Radium wrote:
On Jul 4, 8:44 pm, Radium wrote:

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

OOPS! Totally forget bout da link!

http://72.14.253.104/search?q=cache:...omic.princeton...

(OT) : Off-Topic "BS" Snipped - Please Do Not Read -or- Re-Post
{Radium}

"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

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.

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.

On Fri, 06 Jul 2007 01:25:02 GMT, wrote:

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.

No, it's just a qualitative restatement of Maxwell's theorems.
Changing e-field makes H-field, changing H-field makes e-field, and
they toodle off into the sunset at the speed of light.

John

On Thu, 12 Jul 2007 08:52:24 -0700, John Larkin wrote:
On Fri, 06 Jul 2007 01:25:02 GMT, wrote:
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.

No, it's just a qualitative restatement of Maxwell's theorems. Changing
e-field makes H-field, changing H-field makes e-field, and they toodle off
into the sunset at the speed of light.

Exactly. The Yin calls forth the Yang, and in their cosmic dance, they
create Manifestation. ;-)

Cheers!
Rich
--
For more information, please feel free to visit http://www.godchannel.com