Author Topic: New ELT Question  (Read 4004 times)

Offline keko126.5

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New ELT Question
« on: October 05, 2005, 03:01:12 AM »
Ive heard about these new ELT thingys that are '406 beacons' Can You pick those up on a scanner at 406.000? I put it in my 'Emergency Bank' that has 121.5, 406, and 27.065(CB ch.9). Both GA crashes we had here over the summer were picked up on 121.5 not on 406.  I know that you guys are probably more confused then i am right now but any feedback is appreciated. :D



Offline dave

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Re: New ELT Question
« Reply #1 on: October 05, 2005, 05:59:08 AM »
Quote from: keko126.5
Ive heard about these new ELT thingys that are '406 beacons' Can You pick those up on a scanner at 406.000? I put it in my 'Emergency Bank' that has 121.5, 406, and 27.065(CB ch.9). Both GA crashes we had here over the summer were picked up on 121.5 not on 406.  I know that you guys are probably more confused then i am right now but any feedback is appreciated. :D


Confused about what?

Third generation ELT's operate on 406.025 MHz and your scanner should pick them up just fine.  Keep in my mind, though, that the ground-to-ground range of an ELT will be a little less on 406MHz than on 121.5MHz since UHF signals incur more path and obstacle loss.  For air-to-ground obviously this is less of an issue.  406MHz ELT's are designed mainly to have satellites pinpoint them, however each 406MHz ELT also includes a legacy 121.5MHz continuous signal beacon to aid Search and Rescue Teams trained using that technology.

I saw a presentation once on 406MHz ELT's...here is how system accuracy compares between 406 and 121.5:

121.5 MHZ ELT:
12 nautical mile (nm) radius, 452 sq nm
6 hour notification, average
60-100mW transmitter

406.025 MHz ELT:
5 watt transmitter (sends brief databurst once per minute)
2nm radius, 12.5 sq nm
1 hour notification, average
25mW 121.5 beacon

406.025 MHz ELT with GPS:
5 watt transmitter (sends brief databurst once per minute)
.05nm radius, .008 sq nm
5 minute notification, average
25mW 121.5 beacon

Note that one of the main purposes of 406 MHz beacons is that there are SARSAT and GOES satellites that receive those beacons, and each beacon has a unique digital identifier that lets Search and Rescue personnel know the tail number of the aircraft (if the ELT is registered).  If the aircraft is equipped with a 406MHZ ELT with GPS, then the geographic coordinates are known as well.

Dave