Re: [FT]Flashes was: A couple of quick replies

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On 26 Mar 2001 KH.Ranitzsch@t-online.de wrote:

> 
> >Absender: derk@cistron.nl
> > On the other hand, such extremely high powered pulses are just about
> > impossible not to detect. 
> 
> If I understood the proposal correctly, these would be 'flare 
> grenades', fired some distance from the ship. This makes it difficult
to detect 
> the launching ship unless it, too, is illuminated by the flash. You
would 
> need directional flashes.

Mmm. Okay, I didn't read it as such. You'd need to have very accurate
info
on the timing of the fired pulse, as well as the position, to get your
ranging right. And of course it would be sort of obvious what you're
doing, you're just not giving your exact position away, but still your
general whereabouts.

Also, it's going to light up your own ship in an even stronger way, to
the
enemy? Or is it a directional flare grenade? I'm gonna reread the
original
post :)

> > Also, there's a lot you cannot measure this way,
> > which you could measure with a longer, low powered signal, like 
> > target speed (doppler shift). 
> 
> You don't need really long signals to measure doppler shift, just 
> something that has a well-defined spectrum.

Well, that's the problem with an extremely short pulse, isn't it? I'm
guessing this would appraoch the characteristics of a Dirac pulse, and
would therefore be rather broadband. Would be very hard to measure the
doppler, on that, as the doppler shift is orders of magnitude beneath
the
bandwidth of the transmitted signal.

Cheers,

   Derk
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