Do magnetars emit audible LW AM radio waves that can be heard on receivers?

Hi:

Do magnetars emit AM radio waves below the medium-wave range? If so,
how do we detect these waves? Can these waves be heard on the AM
radio? If so, what do they sound like?


Thanks,

Radium

On Fri, 13 Jul 2007 20:04:13 GMT, Sam Wormley
wrote:

Why would you expect a star to generate amplitude modulation?

Why would you expect it to generate anything else? These sorts of
objects are rotating at high speed, which modulates the amplitude we
receive. While there are probably other types of modulation as well, the
amplitude variation is the dominant effect. Of course, magnetars are
emitting mainly hard x-rays. I don't know that there's enough long
wavelength energy to detect on any kind of ordinary radio.

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

In rec.radio.amateur.space Radium wrote:
Hi:

Do magnetars emit AM radio waves below the medium-wave range? If so,
how do we detect these waves? Can these waves be heard on the AM
radio? If so, what do they sound like?

Frequencies above approximately 100 MHz almost always get through
the ionization layers.

Frequencies in the approximate range of 10 MHz to 100 MHz sometimes
get through

Frequencies below approximately 10 MHz almost never get through.

So, if by "the AM radio" you mean a Broadcast Band radio which
runs from about .5 MHz to 1.2 MHz, not a chance in hell of ever
hearing anything from off the planet.

Try again.

--
Jim Pennino

Remove .spam.sux to reply.

On Jul 13, 2:15 pm, wrote:
In rec.radio.amateur.space Radium wrote:

Hi:
Do magnetars emit AM radio waves below the medium-wave range? If so,
how do we detect these waves? Can these waves be heard on the AM
radio? If so, what do they sound like?

Frequencies above approximately 100 MHz almost always get through
the ionization layers.

Frequencies in the approximate range of 10 MHz to 100 MHz sometimes
get through

Frequencies below approximately 10 MHz almost never get through.

So, if by "the AM radio" you mean a Broadcast Band radio which
runs from about .5 MHz to 1.2 MHz, not a chance in hell of ever
hearing anything from off the planet.

Try again.

Okay. But what if this is a supercooled AM radio receiver on a
spaceship orbiting Earth? If I am on a space station like MIR and this
station has a supercooled AM radio 44.1 KHz frequency receiver, will I
hear anything specific of magnetars?

44.1 KHz is the carrier-frequency this hypothetical receiver receives.

I place the frequency of this hypothetical AM radio carrier wave at
44.1 KHz for the same reason CDs use a sample rate of 44.1 KHz -- it
is the minimum required to prevent aliasing.

AFAIK, space station orbit earth above the ionosphere so the
limitations [preventing long-waves from outer space from reaching the
Earth's surface] do not apply.

In rec.radio.amateur.space Radium wrote:
On Jul 13, 2:15 pm, wrote:
In rec.radio.amateur.space Radium wrote:

Hi:
Do magnetars emit AM radio waves below the medium-wave range? If so,
how do we detect these waves? Can these waves be heard on the AM
radio? If so, what do they sound like?

Frequencies above approximately 100 MHz almost always get through
the ionization layers.

Frequencies in the approximate range of 10 MHz to 100 MHz sometimes
get through

Frequencies below approximately 10 MHz almost never get through.

So, if by "the AM radio" you mean a Broadcast Band radio which
runs from about .5 MHz to 1.2 MHz, not a chance in hell of ever
hearing anything from off the planet.

Try again.

Okay. But what if this is a supercooled AM radio receiver on a
spaceship orbiting Earth? If I am on a space station like MIR and this
station has a supercooled AM radio 44.1 KHz frequency receiver, will I
hear anything specific of magnetars?

Generally, super cooled electronic components stop working.

Try again.

44.1 KHz is the carrier-frequency this hypothetical receiver receives.

A super stupid frequency to pick. Generally for listening for natural
phenomena, you want a wide as possible bandwidth given the noise
floor.

I place the frequency of this hypothetical AM radio carrier wave at
44.1 KHz for the same reason CDs use a sample rate of 44.1 KHz -- it
is the minimum required to prevent aliasing.

Yeah, for digitized, audible music, you twit.

Are you expecting to hear alien rock and roll?

An AM receiver isn't digitizing anything, sample rates don't apply,
and aliasing doesn't apply.

Try again, idiot.

AFAIK, space station orbit earth above the ionosphere so the
limitations [preventing long-waves from outer space from reaching the
Earth's surface] do not apply.

Probably the only thing you got right.

--
Jim Pennino

Remove .spam.sux to reply.

On Jul 13, 4:55 pm, wrote:

In rec.radio.amateur.space Radium wrote:

Okay. But what if this is a supercooled AM radio receiver on a
spaceship orbiting Earth? If I am on a space station like MIR and this
station has a supercooled AM radio 44.1 KHz frequency receiver, will I
hear anything specific of magnetars?

Generally, super cooled electronic components stop working.

Isn't a super cooled receiver less vulnerable to thermal noise than a
receiver of a higher temperature? This is why SETI super-cools their
radio receivers. So that the heat will not generate electric currents
that would drown-out the intended signals in hiss.

44.1 KHz is the carrier-frequency this hypothetical receiver receives.

A super stupid frequency to pick. Generally for listening for natural
phenomena, you want a wide as possible bandwidth given the noise
floor.

But humans only hear from 20 to 20,000 Hz. So why use a higher
frequency?

From what you think, what is the best frequency for listening to
magnetars and other natural phenomena?

I place the frequency of this hypothetical AM radio carrier wave at
44.1 KHz for the same reason CDs use a sample rate of 44.1 KHz -- it
is the minimum required to prevent aliasing.

An AM receiver isn't digitizing anything, sample rates don't apply,
and aliasing doesn't apply.

Isn't it true that the carrier-frequency must be at least 2x the
highest intended frequency of the modulator signal?

I am not talking about sample rates. I am talking about carrier
frequency. From the answers to my previous questions regarding carrier
frequencies, I thought it was established that you mathematically
can't have a modulator frequency more than 0.5x the carrier-frequency.
What happened?

Since humans hear up to 20 KHz it is mathematically-required that the
carrier frequency be at least 40 KHz or 2 x 20 KHz. Due to physical
factors it would be most practical to use a carrier frequency slightly
higher than 2x the maximum intended modulator frequency -- hence 44.1
KHz.

In rec.radio.amateur.space Radium wrote:
On Jul 13, 4:55 pm, wrote:

In rec.radio.amateur.space Radium wrote:

Okay. But what if this is a supercooled AM radio receiver on a
spaceship orbiting Earth? If I am on a space station like MIR and this
station has a supercooled AM radio 44.1 KHz frequency receiver, will I
hear anything specific of magnetars?

Generally, super cooled electronic components stop working.

Isn't a super cooled receiver less vulnerable to thermal noise than a
receiver of a higher temperature? This is why SETI super-cools their
radio receivers. So that the heat will not generate electric currents
that would drown-out the intended signals in hiss.

44.1 KHz is the carrier-frequency this hypothetical receiver receives.

A super stupid frequency to pick. Generally for listening for natural
phenomena, you want a wide as possible bandwidth given the noise
floor.

But humans only hear from 20 to 20,000 Hz. So why use a higher
frequency?

From what you think, what is the best frequency for listening to
magnetars and other natural phenomena?

I place the frequency of this hypothetical AM radio carrier wave at
44.1 KHz for the same reason CDs use a sample rate of 44.1 KHz -- it
is the minimum required to prevent aliasing.

An AM receiver isn't digitizing anything, sample rates don't apply,
and aliasing doesn't apply.

Isn't it true that the carrier-frequency must be at least 2x the
highest intended frequency of the modulator signal?

I am not talking about sample rates. I am talking about carrier
frequency. From the answers to my previous questions regarding carrier
frequencies, I thought it was established that you mathematically
can't have a modulator frequency more than 0.5x the carrier-frequency.
What happened?

Since humans hear up to 20 KHz it is mathematically-required that the
carrier frequency be at least 40 KHz or 2 x 20 KHz. Due to physical
factors it would be most practical to use a carrier frequency slightly
higher than 2x the maximum intended modulator frequency -- hence 44.1
KHz.

If you had the slightest bit of education or common sense, you would
be asking a question that makes sense instead of going on forever
about the minutiae of what makes your questions idiotic.

Here's a question that makes sense:

Are there any sources of RF energy outside our solar system that
could possiblely be detected given an environment free of the
constraints of the ionsphere and man made noise?

If so, what frequecy or frequencies would they be seen at and what
would be the general characteristics of such a signal?

Also, the same question but operating from the Earth's surface.

And this is an astronomy/astro-physics question, not an electromagnetics
question.

Notice there is nothing in there about "supercooling", modulation
type, sampling rates, or any of the other nonsense in your question.

Babbling twit.


--
Jim Pennino

Remove .spam.sux to reply.

"Radium" wrote in message
oups.com...
...
Isn't it true that the carrier-frequency must be at least 2x the
highest intended frequency of the modulator signal?

No.

I am not talking about sample rates. I am talking about carrier
frequency. From the answers to my previous questions regarding carrier
frequencies, I thought it was established that you mathematically
can't have a modulator frequency more than 0.5x the carrier-frequency.

No. You can't have a sampling rate less than twice the highest
frequency in the source without aliasing, but that refers only
to sampling.

What happened?

At a guess, you misunderstood the context of the answers to
your previous questions, or those who answered misunderstood
the context of your questions.

HTH
George

On 2007-07-14, wrote:

If you had the slightest bit of education or common sense, you would
be asking a question that makes sense instead of going on forever
about the minutiae of what makes your questions idiotic.

This is Radium's usual posting style - to produce some random,
obvious ideas as if no one has ever considered them before, and
then to lightly dismiss any practical difficulties anyone points
out as trivial. After all, he's the genius, you're expected to
put in all the leg work to make a ridiculous idea actually work.

I've seen him all to many times before on the likes of
alt.comp.hardware.homebuilt. It's worth looking at the Goggle
archives to see just what nonsense he comes up with. My favourite
example is Radium's understanding of semiconductors:

Why is silicon needed in the 1st place? For that matter, why any semi-
conductor? Why not just use the copper electric circuits? Semi-
conductors are half-way between conductor and insulator?

I think that that says it all.

--
Andrew Smallshaw

On Jul 14, 1:17 am, "George Dishman" wrote:
"Radium" wrote in message

oups.com...
..

Isn't it true that the carrier-frequency must be at least 2x the
highest intended frequency of the modulator signal?

No.

Karl Uppiano sharply disagrees.

Karl Uppiano explained in http://groups.google.com/group/sci.e...cea47a5?hl=en&
:

The highest modulating frequency for AM must be less than 1/2 the carrier
frequency. Conversely, the lowest carrier frequency must be twice the
highest modulating frequency. Period. I don't care what specific frequencies
and/or energies and/or colors you propose.

If you want to modulate at 20KHz, the carrier must be at least 40KHz. It is
no coincidence that CD audio uses a 44.1KHz sample rate. It is essentially
the same principle. If you exceed the Nyquist criterion, the sidebands
overlap the baseband (i.e., aliasing occurs) and you cannot unambiguously
decode the original modulation.

So who is right and who is wrong? I am so interested yet so frustrated
over this!

I keep getting conflicting answers about this topic. Its driving me
crazy!!!!!!!!!!!!!!!!!

WTF is going on here??????????????????!!!!!!!!!!!!!!!!!!!!?!?!?!?! ?!