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Re: P3D Dreaming



I agree completely.  I was only making an independed comparison of
identical EIRPs on 2 meters and 2.4 Ghz and making sure that people
undrstood that identical apature antennas are required, but that the
DIRECTIVITY changes drastically.

Yes, the link budget will not work to P3D to an omni.  But what ever
antenna directivity you use on 2m, it will be 13 dB narrower on 2.4
GHz for the same EIRP.  My choice of a 19" whip was not intended for the
P3D link budget, but only to show the big difference in directivity that
antenna gain makes.

de WB4APR, Bob

 On Tue, 1 Aug 2000, Jon Ogden wrote:

> > 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...
> 
> Bob,
> 
> A 19" whip won't work for a high earth orbit satellite.  When the bird is at
> 26,000 miles out, an omni-directional whip just won't cut it.  It's a lot
> different than when the bird is at 300 miles!
> 
> I am afraid for P3D, you'll have to give up your concept of a whip on the
> car to work the satellite.
> 
> And yes, I'd rather have the gain and put up with the tracking.  I've tried
> the whip in the car bit and it just doesn't work as good.
> 
> 73,
> 
> Jon
> NA9D
> 
> 
> 

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