[EMAIL PROTECTED] (Glenn LeBrasseur) writes:
> Unfortunately no part of 802.11a is in the amateur spacecraft
> range. This kind of makes sense with regard to interference, since it
> would be so easy for a spacecraft to interfere with a large number of
> terrestrial 802.11a stations.
The reverse is *far* more important, at least to me. ;-)
A large body of unlicensed terrestrial transmitters bringing up the noise
floor could make it *very* hard to hear amateur satellite downlinks, which
are typically far too weak to cause any significant interference to
terrestrial stations. In theory an uplink could cause interference to
802.11a stations, but since highly directional antennas are typically used
aimed at the satellite, any real interference caused by an uplink is likely
to be rare.
> Power levels
> are limited to the license class , which for the technician class
> is 200 watts, and the overall power limit stated in CFR 47-97.313(a)
> and (b).
I think you mis-read that part of the rules. The actual power limit for all
licensed amateurs on that band should be 1.5kW PEP. However, the restriction
in the preceeding section on spread-spectrum transmissions likely applies, so
the limit may be 100W. In practice, these distinctions are not important,
because making gobs of power on C band requires *serious* heroics. A watt is
pretty easy, a few watts is plausible, serious uplinks for things like EME
typically involve TWT amplifiers, mongo amounts of heat sink mass, and/or water
cooling... you *really* don't want or need lots of watts for this task.
> The way I see it, using 802.11a will work for us up at larger amateur
> power levels until we actually get into space, and either need the
> higher power levels (more than 3 watts say) for the link budget, or
> our footprint increases and we actually become a spacecraft.
When you become a spacecraft, you'll want/need to coordinate use of frequencies
in the amateur satellite sub-bands. As long as you're on something like a
ballistic trajectory, the terrestrial rules should continue to apply.
73 - Bdale, KB0G
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