ELT's are a joke

I've said it before, though I haven't done an extensive web search on
it,
There's gotta be an elt available that sends one short burst with your
exact GPS location to a satalite, instead of having the boy scouts try
to hunt down an AM signal with a directional antenna, while the
transmitter is operating continuosly draining those questionable D
cells that have been in the unit for...how long? Hokey Smokes! let's
get caught up with the '90's. It's crazy, flying along and having
center call you to ask if you hear an elt signal while you're at FL310
over the LA basin. Yeah, we hear it, so now what? If it were a gps
signal, center would know right away it's just a helicopter sitting in
the hanger an hour after a firm landing. A millisecond burst would
require very little power, and could encode position, aircraft type &
"N" number and whatever else. The signal only needs to be sent once,
and would save time, money, and lives. A hunter or hiker or pilot
could add a brief text message as well, to indicate urgancy.
Oh, one other thing, considering the cost of a gps & transmitter, it
should be affordable to anyone, maybe the price of a 'chute or less.
Why don't we all have these?
-Dan

I believe the part about not doing a search.

You pretty accurately describe the new 406 Mhz personal locator beacons.

http://www.avweb.com/news/reviews/185236-1.html

http://www.provantage.com/buy-220814...ectronics-fast
find-plus-406-epirb-personal-location-beacon-plb-gps-shopping.htm

Larry Pardue 2I
n5lp.net



I've said it before, though I haven't done an extensive web search on
it,
There's gotta be an elt available that sends one short burst with your
exact GPS location to a satalite, instead of having the boy scouts try
to hunt down an AM signal with a directional antenna, while the
transmitter is operating continuosly draining those questionable D
cells that have been in the unit for...how long? Hokey Smokes! let's
get caught up with the '90's. It's crazy, flying along and having
center call you to ask if you hear an elt signal while you're at FL310
over the LA basin. Yeah, we hear it, so now what? If it were a gps
signal, center would know right away it's just a helicopter sitting in
the hanger an hour after a firm landing. A millisecond burst would
require very little power, and could encode position, aircraft type &
"N" number and whatever else. The signal only needs to be sent once,
and would save time, money, and lives. A hunter or hiker or pilot
could add a brief text message as well, to indicate urgancy.
Oh, one other thing, considering the cost of a gps & transmitter, it
should be affordable to anyone, maybe the price of a 'chute or less.
Why don't we all have these?
-Dan

......A millisecond burst would
require very little power, and could encode position, aircraft type &
"N" number and whatever else. The signal only needs to be sent once,
and would save time, money, and lives. A hunter or hiker or pilot
could add a brief text message as well, to indicate urgancy.
Oh, one other thing, considering the cost of a gps & transmitter, it
should be affordable to anyone, maybe the price of a 'chute or less.
Why don't we all have these?

The 1.6 GHz EPIRBs are already available:


The 1.6GHz EPIRB uses the INMARSAT satellites in geostationary orbit.
These satellites do not fly around the planet and appear to remain in
one fixed spot over the earths surface, (the stationary part of
geostationary).


They are equipped with a GPS receiver so that when they are activated
the alert signal, beacon ID and beacon position are transmitted.


See http://www.navtec.de/english/epirb2.htm

Tony V.

At 20:00 14 November 2003, Buck Wild wrote:
I've said it before, though I haven't done an
extensive web search on it, There's gotta be
an elt available that sends one short burst
with your exact GPS location to a satalite

What you are looking for is a 406 MHz ELT. They transmit
a message burst every 50 seconds, rather than emitting
a continuous signal. The reason a priodic message
is required is that the primary emergency receivers
are on polar orbiting satellites, and there may not
be one overhead at any given moment. The aircraft
versions also supports broadcasting position info using
an external GPS connected via an ARINC 429 bus.

Why don't we all have these?

Most because a TSO'd 121.5 MHz ELT costs around $200,
whereas a TSO'd 406 Mhz ELT costs $5000+ (a GPS with
a 429 bus will cost you a few thousand more). You
can get a marine 406 MHz ELT for under $1000, but they
don't have a G-switch...

Marc

Earlier, Buck Wild wrote:

...There's gotta be an elt available that
sends one short burst with your exact
GPS location to a satalite...

Sorta off-topic, but sorta not:

Last year, me and a couple of friends sitting around
the table at Air Sailing had a big ol' discussion about
that. One of the controversial ideas that came out
of that was that perhaps the best predictor of accident
survival was how long it took emergency crews to reach
the accident site. What we figured is that glider pilots
need something like the OnStar system that they put
in Cadillacs and such.

What we hashed out was a GPS-enabled system capable
of sensing a crash impact, and further capable of determining
the proximity to civilization and the nature of the
surrounding terrain. With that information at hand,
the box would assess the impact energy and location,
and place a satellite call for a MediFlight helicopter
or ambulance as appropriate.

Just some into-the-box thinking.

Bob K.

Larry Pardue wrote:
I believe the part about not doing a search.

You pretty accurately describe the new 406 Mhz personal locator beacons.

Though much better thatn the 121.5 MHz units, I don't believe that the
406's transmit GPS coordinates like the 1.6 GHz units do - they use
doppler shift instead. My understanding is that the 406 MHz units
provide a 1KM resolution. Much better than the 121.5's but if you go
down into a forest.... not good enough, IMHO. See
http://www.navtec.de/english/elts.htm

Tony V.

Sorta off-topic, but sorta not:

Also a bit off topic but this summer (July), a club member made an
"off-field landing" in a forest in an LS4-b. He was slightly injured and
was trapped in the aircraft. He radiod his GPS cooordinates to a club
tow plane, 20 miles away. The plane landed at the gliderport, loaded an
oberver with a portable GPS and set off. Even though they had the exact
position, it took several minutes to spot him though the forest canopy.
They circled over the crash site and guided rescuers until help arrived.

The police later credited the tow plane crew for significantly reducing
the rescue time.

Tony V.

Tony Verhulst wrote:
Though much better thatn the 121.5 MHz units, I don't believe that the
406's transmit GPS coordinates like the 1.6 GHz units do - they use
doppler shift instead. My understanding is that the 406 MHz units
provide a 1KM resolution. Much better than the 121.5's but if you go
down into a forest.... not good enough, IMHO. See
http://www.navtec.de/english/elts.htm

A 406 MHz ELT can transmit GPS position. I believe EPIRB was designed
primarily for marine applications. The primary receivers are on
geostationary satellites, which may not be very helpful if you happen to
be in a canyon, or on the wrong side of a mountain...

Marc

(Buck Wild) wrote in message . com...


the price of a 'chute or less.
Why don't we all have these?
-Dan

A single tone modulated am transmitter can consist of very few parts.
You're thinking something that can be activated after the crash has
already occurred, highly unlikely all that circuitry would function
after a crash.

However, let us know how your development comes along. Just remember
the market is too small to pay more than $50 per year to the
developer.

Sorry, dud, but digital encoding may be relatively simple and now
small, but making complex and accurate is going to blow the hell out
of development costs.

Is a APRS (Automatic Postition Reporting System) enabled ham radio a
reasonable substitute?

Intro: http://nwaprs.org/downloads/WhatIsAPRS.pdf

Way more info: http://web.usna.navy.mil/~bruninga/aprs.html




On 14 Nov 2003 11:49:19 -0800, (Buck Wild) wrote:

I've said it before, though I haven't done an extensive web search on
it,
There's gotta be an elt available that sends one short burst with your
exact GPS location to a satalite, instead of having the boy scouts try
to hunt down an AM signal with a directional antenna, while the