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Re: P3D Dreaming



On Mon, 31 Jul 2000, Jeff Davis gave a good comparison:

> : So, where does that get us?  We have established that 145 MHz noise =
> : 1200K,  and on 2.4 GHz  it's 120K.   That's a factor of 10x quieter at
> :
> : It means that for a given spacecraft e.i.r.p., your ground station
> : antenna on S-band can be 10 times smaller than for the 2 metre band. 

As he noted, this is all based on the premise that 2 meters is 10 times
more noisy.  Otherwise the required atnenna sizes are equal due to the
capture area he also mentioned.

And in that case, for the same EIRP, would you rather have a 19" 2 meter
grounplane whip antenna (no tracking required) or a 13 dB gain antenna
for 2.4 GHz that you have to track in AZ and EL across the sky and also
then have a computer to do the work.  Yes, they are the same phyusical
"size" but you pay for it by having to put up wtih greater directivity at
the higher frequency...

Just a thought...

de WB4PAR, Bob


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