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Re: RAgeo, a low cost GEO bird



On Mon, 21 Jul 2003, Lowell White wrote:

> The idea of possibly offering 10M operation, ...  is attractive...

It appeals to me because it is a big band and under used most of the time.
When it is useable, you dont need the satellite either.  Further, its path
loss  (to a similar scaled antenna) is 23 dB less than at UHF.  But using
it as a downlink has to subtract from that, the atmospheric noise on that
band (anyone know what this typically is in dBm?

Using it as an uplink has several advanateges:

1) the geo bird is far from the atmosphere and should be able to hear all
of that 23 dB link budget advantage.

2) It should be able to hear a mobile with only a whip on the uplink

3) Most users will have comparably equal uplinks, reducing the number one
problem with wideband transponders and that is OVERPOWERING by some
stations.    Most people on 10m would use a dipole or a whip.

4) Most users would be using the readily available and cheap $150 SSB
transceivers as their uplinks and most of these rigs operate at 25W
or so.  Again, everyone being in about the same class...

5) High Power AMPS for 10m are illegal to be sold in the USA and so fewer
people will have a tendency to run tooooo much power..

Just some ideas.  We need to do the link budgets... AND know the noise
floor both at geo and terrestrial locations...

de WB4APR, Bob


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