On Sat, 08 Mar 2008 12:40:08 -0500, mm
wrote:

Today on the news I heard that a big bunch of electronic garage door
openers weren't working in Churchville Maryland because the govt. at
the Aberdeen Proving Grounds was doing something with a satellite or
something. Tomorrow their going to do the same thing around Aberdeen.

People are paying techs to change the freqs, but some may have paid
for other repairs by mistake, one would assume.

Someone in charge admits he didn't get the word out well enough.

1) Don't they assign frequency ranges to things so that this sort of
thing doesn't happen?


No, they don't. Shared and the primary user (military) has priority,
all non-primary users much accept any interference generated by the
primary user.


2) How could the use of a frequency mess up the garage door openers?

Well, if two signals could occupy the same frequency, we'd only need
televisions with one channel, right?


Even if the govt. signal was stronger, why wouldn't the opener still
work?

OK, so your car's FM radio picks up a given station. It picks up the
strongest station, in fact if that strongest station were to suddnly
stop transmitting (say a power or equipment failure) you'd then
probably pick up the next strongest station on the same frequency...
Strongest wins, in this and in fighting.

If the govt. signal was picked up by the opener, how come the
doors didn't open or shut. (Apparently they didn't since they would
surely have mentioned that.)

Huh? So the military signal overpowers the remote... How's it going to
work?




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