> On Jul 15, 10:05 am, j...@specsol.spam.sux.com wrote:
>

>> The bigger issue with the frequency (other than plain stupidity) you
>> have choosen is that to be able to say you are hearing signals from
>> something specific in the sky as opposed to everything in the sky,
>> you need to have antenna directivity.

> Why does it need to be around 500 miles? Atomic-clock wrist-watches
> receive extremely long wavelengths and are able to do so with their
> tiny sizes. Couldn't something similar be done for my 'application'?
> If not, then why?

> On Sun, 15 Jul 2007 00:55:01 GMT, j...@specsol.spam.sux.com wrote:

>>The definitions for all types of modulation involve a carrier frequency.

>

>>Since natural phenomena generate broad band noise, it is arm waving
>>at best to call the variations in amplitude "amplitude modulation".

>

>>What it is is a broad band source that periodically varies in signal
>>strength.

>
> There's nothing that defines how narrow a band need be to qualify as a
> "carrier". Many modern communication systems are spread spectrum, which
> means the carrier may be very broad. Such systems are certainly
> modulated. Also, many astronomical sources are not broadband at all, but
> radiate across a narrow spectrum.

> On Sun, 15 Jul 2007 16:15:01 GMT, jimp@specsol.spam.sux.com wrote:

>>>>Nope, mathematically AM is defined as a single carrier frequency
>>>>multipled by the modulation frequency. That you get a variation in
>>>>amplitude is an effect, not a definition.

>>

>>> Reference? I think you are confusing a single definition of AM with all
>>> other definitions of the term.

>>
>>How about this one:
>>
>>http://www.rfcafe.com/references/electrical/amplitude_modulation.htm

> That isn't a mathematical definition of amplitude modulation. It's an
> example of an implementation of amplitude modulation for the purpose of
> deliberately encoding information. And in fact, it's idealized since no
> carrier frequency can ever be perfectly discrete. I've never seen a rule
> for how narrow or broad a carrier needs to be in order for an amplitude
> modulated form of it to be allowed to carry the term "amplitude
> modulation". And I'm sure you haven't either.

>You ignored the most important question; is the square root of -1 i or j?

> On Mon, 16 Jul 2007 00:55:01 GMT, jimp@specsol.spam.sux.com wrote:

>>You ignored the most important question; is the square root of -1 i or j?

> I use i. But I certainly recall electronics classes where j was used to
> avoid confusion. I don't worry too much about the choice of symbol.

> On Sat, 14 Jul 2007 23:36:08 GMT, Sam Wormley mchsi.com>
> wrote:
>

>> Amplitude modulation, in the communications world, has a definite
>> structure--I suspect that magnetar spectra don't exhibit amplitude
>> modulation characteristics.

>
> A magnetar is a type of pulsar. You have a signal at some frequency (or
> range frequencies) that varies in amplitude with time (as the object
> spins). That's the very definition of amplitude modulation. Nearly every
> radio source around shows some degree of amplitude modulation as the
> result of spin. This includes objects radiating well out of the radio
> band, as well. Optical binaries exhibit AM. Starspots show up as AM.
> Rotating asteroids are AM. Cepheids. Cataclysmic variables. Etc.
>
> _________________________________________________
>
> Chris L Peterson
> Cloudbait Observatory ...

> http://en.wikipedia.org/wiki/Heliosphere
>
> Both the material within the region and the ISM are almost
> entirely ionised so are in a form known as "plasma", a
> soup of charged particles. One of the feautures of plasma
> is that is absorbs low frequency signals below what is
> called the "plasma cutoff frequency". Basically below
> the VHF band, space becomes increasingly opaque and signals
> from stars don't reach us.

>From the above link, it seems that a higher-frequency radio wave would

>There you have it.
>
>The basic problem is we speak two different languages; it's j.

> On Mon, 16 Jul 2007 01:35:01 GMT, jimp@specsol.spam.sux.com wrote:

>>There you have it.
>>
>>The basic problem is we speak two different languages; it's j.

> No, I'm bilingual. You apparently are not .

> In rec.radio.amateur.space KLM mchsi.com> wrote:
>

>> Radium wrote:

>

>>> On Jul 13, 2:15 pm, j...@specsol.spam.sux.com wrote:

>>>> In rec.radio.amateur.space Radium gmail.com...