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Author: RadiumRadium Date: Jul 13, 2007 12:50
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
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Author: Sam WormleySam Wormley Date: Jul 13, 2007 13:04
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?
>
Why would you expect a star to generate amplitude modulation?
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Author: Chris L PetersonChris L Peterson Date: Jul 13, 2007 13:23
On Fri, 13 Jul 2007 20:04:13 GMT, Sam Wormley mchsi.com>
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
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Author: jimpjimp Date: Jul 13, 2007 14:15
In rec.radio.amateur.space Radium gmail.com> 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.
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Author: RadiumRadium Date: Jul 13, 2007 14:50
> In rec.radio.amateur.space Radium gmail.com> 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.
> ...
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Author: jimpjimp Date: Jul 13, 2007 16:55
In rec.radio.amateur.space Radium gmail.com> wrote:>> In rec.radio.amateur.space Radium gmail.com> 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. ...
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Author: RadiumRadium Date: Jul 13, 2007 17:36
> In rec.radio.amateur.space Radium gmail.com> 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?
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Author: jimpjimp Date: Jul 13, 2007 18:35
In rec.radio.amateur.space Radium gmail.com> wrote:>> In rec.radio.amateur.space Radium gmail.com> 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?
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Author: George DishmanGeorge Dishman Date: Jul 14, 2007 01:17
> 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
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Author: Andrew SmallshawAndrew Smallshaw Date: Jul 14, 2007 13:08
>
> 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.
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