1ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities Distress Beacon Frequencies Primary: –121.5 MHz, and its harmonics (243 MHz) –243 MHz, military frequency –406 MHz, next generation distress beacons transmitting location, tail number or boat identification, etc. Training: – MHz Required by FAA as of 31 January MHz is no longer authorized for training

2ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities Distress Beacons There are three types of beacons used to transmit distress signals: EPIRBs (for maritime use) ELTs (for aviation use) PLBs (used for land-based applications)

3ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities Line of Sight Transmission –ELTs are limited to Line of Sight propagation and reflections –You don’t always need to hear the ELT Carrier wave may be broadcasting with no audible sweep

4ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities What Else Can Affect An ELT Signal? Power lines Fence Line (signal can follow) Reflections off of obstacles Hangars Moving Target Not using the Equipment Properly - See Picture at Right What’s wrong with this?

5ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities Triangulation Documenting team movements is logical, and can allow the team to locate the distress beacon sooner

6ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities Triangulation Continued You must be able to receive the signal –Center up DF unit on the signal –Take the magnetic bearing (shoot an azimuth) –Correct for magnetic variation East is least, West is best –Plot your bearings (draw a line) on map –The ELT should be where the lines cross!

7ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities What information is needed for the IC? Make Model and Model # Manufacturer Location Description Approximate location (Latitude & Longitude) Owner Tail Number or Boat Name and Number Time Found and Time Shut-off

8ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities What information is needed for the IC? Continued Switch Position on ELT or EPIRB: ON, OFF, or ARM Manufacture Date Battery Expiration Date Information which could indicate reason for accidental or justified activation of ELT or EPIRB NOTE: If you can’t get certain information, don’t worry, the AFRCC understands

9ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities L-Per in DF Mode DF mode measures equal strengths of signal –Not completely accurate, but good enough! –When needle is centered, ELT could be either direction –Needle always POINTS to the ELT (DF=Follow the needle) –Use a TURN to TELL if the ELT is in front or behind you

10ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities DF = Follow the Needle

11ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities L-Per in REC Mode Receive Mode Measures Signal Strength only –Signal comes from the direction of the arrows on the antenna (to your left)

12ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities Body Shielding A method of beating reflections at close range Can use L-Per Radio Shack JETSTREAM radio is better and CHEAP! Body blocks out the signal –Called a NULL –Null should be at your BACK

13ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities Body Shielding Continued At extremely close range, a 2m VHF radio un-squelched may work –This works ok when trying to figure out a particular aircraft on a flight line, it will probably not identify a particular hangar

14ELTDF..PPT LAST REVISED: 9 JULY 2008 Citizens Serving Communities L-Per Receiver