writer needs help

OK not to hijack this thread, but what you and Peter are saying about ELT's
has me confused. I assume the OP is talking about the standard,
been-around-for-twenty-years, 121.5 MHz ELT. How in the world would a
satellite orbiting thousands of miles above the earth pick up this signal,
let along get a fix on it? This is something I have never heard of.

"Ron Natalie" wrote in message
m...
wendy wrote:

Pretty much. There are multiple flavors of ELT, but the one most
aircraft has is pretty lousy. False activiations and failure to
activate are common. These old ELT's take two satellite passes
to get any indication and even those position reports are pretty coarse.
In fact, the support for satellite detection of these old elt's is
scheduled to be pulled in 2009.

I assume the OP is talking about the standard,
been-around-for-twenty-years, 121.5 MHz ELT. How in the world would a
satellite orbiting thousands of miles above the earth pick up this signal,
let along get a fix on it? This is something I have never heard of.

Not by accident. There are satellites that are designed to (in part)
look for such signals. I don't think those satellites are thousands of
miles above the earth, only a few hundred miles is needed to get into
space. In any case, their receivers are =very= good, and there isn't
anything in the way to block the signal. You'd be surprised how far
signals (including ordinary acoustic signals like conversation) carry
under ideal conditions.

Jose
--
Money: what you need when you run out of brains.
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Jose wrote:
I assume the OP is talking about the standard,
been-around-for-twenty-years, 121.5 MHz ELT. How in the world would a
satellite orbiting thousands of miles above the earth pick up this
signal,
let along get a fix on it? This is something I have never heard of.


Not by accident. There are satellites that are designed to (in part)
look for such signals. I don't think those satellites are thousands of
miles above the earth, only a few hundred miles is needed to get into
space. In any case, their receivers are =very= good, and there isn't
anything in the way to block the signal. You'd be surprised how far
signals (including ordinary acoustic signals like conversation) carry
under ideal conditions.

I believe the sats that scan for ELT signals are operated by the
Russians. They notify the FAA or somebody in the US when they pick up a
signal. I've heard that most ELT signals come from boats rather than
airplanes.

Mike W. wrote:
OK not to hijack this thread, but what you and Peter are saying about ELT's
has me confused. I assume the OP is talking about the standard,
been-around-for-twenty-years, 121.5 MHz ELT. How in the world would a
satellite orbiting thousands of miles above the earth pick up this signal,
let along get a fix on it? This is something I have never heard of.

dopler effect; the thing goes biiiiip biiiip biip bip then back to biip
biiip biiiip again :-) when it is at bip, you mark a line on the map
perpendicular to your path; repeat from a few different directions --
these satelites have polar orbits -- and you got a fix.

--Sylvain

I just wrote a little bit hastily:
the thing goes biiiiip biiiip biip bip then back to biip

ok, it's a lousy explanation; but Doppler effect it is
(with two ps);

--Sylvain

"Sylvain" wrote in message
...
I just wrote a little bit hastily:
the thing goes biiiiip biiiip biip bip then back to biip

ok, it's a lousy explanation; but Doppler effect it is
(with two ps);

So, it's really that it goes "biiiiipp biiiipp biipp bipp then back to
biipp"?

Just trying to make sure we've got it straight here.