Emergency Frequency...

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exkalibur

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twolf816 said:
and how would the satellites know you are testing and "disregard signals during this time period"?

...

how in the world if you turn it on for 2 sec is someone gonna know where it came from?
Simple. The first 5 minutes out of each hour, the satellite goes "deaf".

Those satellites are very precise. It can pinpoint your location in a matter of seconds, so don't dick around!

121.5 is, as stated, a guard frequency. You hear all the time, an ATC trying to reach an aircraft on it that isn't answering on their usual channel. The best way to describe it is as an Emergency/Calling/Distress frequency. Just the same as 156.800.
 

ReceiverBeaver

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As to other itinerant traffic heard on 121.5, many times I've heard chit chat there. The pilots picked up the wrong mic or otherwise forgot to use the other radio or switch frequencies. They meant to be chatting on the 123.450 air to air itinerant channel. And I've likewise heard other pilots break in and remind them they were on the emerg. channel. The first parties always say, yeah sorry, and switch frequencies. Simple mistake.
 
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Yeah I've heard them accidentally give the entire cabin announcements over guard. He of course caught all sorts of flack from every other pilot in radio range. These sorts of slip ups were really prevalent right after 9/11.
 

wwhitby

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Those satellites are very precise. It can pinpoint your location in a matter of seconds, so don't dick around!
The newer 406Mhz ELTs are more precise. However, when I was a Ground Team Member/Ground Team Leader trainee in Civil Air Patrol, there were quite a few times that either the first SARSAT pass would place the ELT hit 30-40 miles away from where the active ELT was found. In cases like that, we used the next several passes of the SARSAT to further define the search area.

Since the 121.5 ELTs would get you in the general area, there were also missions where the ELT had either gone off or someone was testing the ELT at rural (grass) strips, and we never found the ELT or aircraft.

Even so, don't ever play around on emergency frequencies and pilots, be sure your beacon is off when you exit the aircraft.

Warren
 

kf4lne

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The D&M Model DM ELT 8.1 I have transmits on both 121.5 and 243.0 at the same time. It uses the 2nd harmonic of 121.5 for the 243.0 side. See attached pic. As far as a pilot not knowing how to turn it off, thats stupid. Most of them have a switch for manual and auto operation. Operating instructions are uber simple. See the box below the arrow labled "DIRECTION OF FLIGHT", thats the operating instructions, very similar to a lamp, To operate, set switch to ON, to deactivate, set switch to OFF. Mine has a pair of what looks like under sized bannanna jacks that when shorted turn it on in the "Auto" mode. BTW, for anyone who wants one you should keep a look for it at the flea markets, the older ones seem to be popping up everywhere. If you get one I suggest removing the battery ASAP. These things make great conversation peices.
 

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wwhitby

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kf4lne said:
As far as a pilot not knowing how to turn it off, thats stupid. Most of them have a switch for manual and auto operation.
I should have been a little more clear on what I wrote. Even though its supposed to take quite a bit of force to set them off, I've seen (first hand) cases where a rough landing set off an ELT. The story I used to use to illustrate checking your ELT was one mission where an ELT was going of in an aircraft tied down on the ramp. I used to carry an AOR 8000 with an S-Meter, since I could use the body blocking direction finding technique, as well as verify that the ELT was indeed off. We found the aircraft and since the aircraft was open, I reset the ELT. I got the model#, maker, etc of the ELT and the tail number of the aircraft. While exiting the aircraft, I backed into one of the wing struts accidentally, and was suprised to hear the ELT start up again! It didn't take a lot of force to set that one off...

The fella who taught me SAR in Civil Air Patrol, and who had been doing SAR for 15+ years at that time, told me that I would be suprised how many pilots exit an aircraft with an ELT active..... He used to stress to aircrews to listen to 121.5 to be sure the ELT was off.

Warren
 
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Stavro35

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I have heard ATC communications with commerical and civil aircraft asking them to attempt contact with flight ______ on "guard" moment's later. I'll hear a pilot trying to reach the aircraft in question on 121.5.. 121.5 for the air is like 156.80 for the water way's.
 

gcgrotz

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Poltergeisty:

I have heard of that being done with a bouy that floats free and activates the ELT when it hits water. There was a book about Hurricane Mitch and the sinking of the Windjammer ship that outlined this in the story. They never found the ship.

I think they are being phased out for the UHF locaters. But somebody will correct me if I'm wrong.
 

lexx2

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twolf816 said:
is 121.5 the only freq ELT Beacons tx on? ive sat in a hanger with my scanner listning to our local regional airport oh...about 500 times and never once heard this...maybe no one uses it here
Yes 121.5 is the only vhf frequency used for an ELT. If you haven't heard one go off at your airport while you were scanning then it means nobody crashed, or had a really hard landing which would set the ELT off, or no one was testing during the period you were listening

and how would the satellites know you are testing and "disregard signals during this time period"?
The satellites can tell what time it is. If the ELT signal stops during the testing period, those monitoring the satellite won't take any further action.

how in the world if you turn it on for 2 sec is someone gonna know where it came from?
They won't. But if it it turned on accidentally had left on in a hangar (the most common false signal generation) direction finding equipment can very quickly determine the location.
 

adkad

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Yesterday a controller at Centennial in Colorado asked a pilot to check to see if he heard an ELT as another pilot reported that he had possibly heard one. As far as I know nothing came of it but, given this thread, I found that interesting. Adkad
 

kicktd

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I know back when I was in CAP during a SAR training weekend we had an actual ELT go off. Supposedly the guy was testing it and forgot to turn it off or was playing with it. Not sure exactly as it's been awhile.

As far as GUARD goes I have yet to program it in my scanner yet but while monitoring Houston Center I heard the controller come back to a pilot and asked him to repeat as he had someone on the GUARD frequency that was over talking everyone.
 

warthog80525

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Elt

While reading this discussion, I searched via google and ran across this article
http://www.aopa.org/whatsnew/newsitems/2005/050811elt.html

The monitoring of the 121.5 frequency via satellite will be eliminated in 2009. Apparently
'they' are going to the 406 MHz satellite monitoring only. 406 MHz uses some digital
encoding when broadcasting that can give aircraft details as well as GPS coordinates.

121.6 is also an ELT frequency, NOT MONITORED, and used for training. Most of the
hand held direction finders have 121.5, 121.6 and 243 as channel assignments. I used
to use this freq for training when we were teaching the SAR folks how to DF a downed
aircraft.

Happy Holidays and happy scanning!
Minor K7YJ Fort Collins, CO
 
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