Joe A. Dellinger (
Fri, 5 Jan 96 18:19:23 CST

	I know nothing about NAVAwhatever, but maybe with what's been said
here we can sort out this "moon paradox".

	It's described as a "fence", so I imagine the transmitters put out
a FAN of energy in the East-West plane, not a pencil beam. We've been told
that you can tell big satellites like the shuttle from small ones because they
take longer to go through the beam: that certainly implies that the fan is
VERY narrow indeed!

	So the argument that "within 5 degrees is good enough" is not correct,
I think.

	OK, what direction does the fence point? The natural guess is that it
is perfectly perpendicular to the ground. But wait, a string of stations all
precisely on the 33rd parallel wouldn't be due East and West of each other,
because the 33rd parallel is NOT a great circle!

	So either the fence is tilted 33 degrees South of vertical, or the
fence is vertical but the stations lie along a great circle instead of a line
of constant latitude. That would mean the Eastern and Western stations would
have to be further South than the central one in Texas.

	Since we don't have enough information to distinguish which is
correct, let's consider the two cases separately:

1) If the beam is indeed tilted 33 degrees South, then there is no need
for the moon to have to pass overhead as seen from one of the stations (as
indeed it can't for a station so far North).

2) If fence does extend straight up (or nearly straight up), there is another
possible way for the moon to intersect it: well East or West of the local
meridian. Think about it: during spring and summer even from mid-Northern
latitudes the Sun does cross into the Northern half of the sky. It doesn't ever
go dead overhead, but it certainly does shine on the Northern side of your
house at sunrise and sunset! In the same way the moon would cross through a
vertical _fence_ as seen from an observer at 33 degrees North.