DF-517 DIRECTION FINDING SYSTEM CLASSROOM TRAINING BASIC OPERATION of the DF-517 DIRECTION FINDING SYSTEM The purpose of this presentation is to present the basic operational characteristics of the DF-517

SAR Direction Finder DF 517 Search and SAR Direction Finder DF 517 Rescue System BY

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Purpose of the direction finder The SAR DF 517 is a precision direction finder was developed for professional SAR (search and rescue) purposes. It has the ability to bear and analyse traditional 121.5 MHz and 243.0 MHz emergency frequencies in the VHF and UHF bands, maritime radio channel 16, and the new digitally encoded 406.025 MHz COSPAS/SARSAT emergency signal. Because of its very short pulse length, the bearing of the COSPAS/SARSAT signal cannot be determined accurately using conventional direction finders. The traditional 121.5 MHz ELT signal that is currently required in U.S. aircraft is a low power signal that operates continuously once activated. The COSPAS/SARSAT signal on 406.025 MHz is a high power signal that is transmitted only once every 50 seconds. The pulse length of this signal is only 400ms, making it impossible to locate using traditional direction finder equipment. This system incorporates a newly developed and patented antenna (small, rugged and wideband), as well as sophisticated bearing analysis algorithms, allowing delivery of a quick and steady indication for both the 121.5 and 406.025 MHz signals. It also has the ability to track a wide range of training frequencies for training exercises. The direction finder was developed for working under stressful mission conditions such as in an aircraft, helicopter or vehicle.

SAR–DF 517 Direction Finder Principles of Operation

Two Modes of Operation EMERGENCY MODE (For Use on Actual SAR Missions) Unit will search for 121.5 MHz, 406.025 MHz, Marine Channel 16 and COSPAS/SARSAT Emergency Signal Transmissions Depending on selection, the unit will either SCAN all of these frequencies or search on a single selected frequency. TRAINING MODE (For Use on Practice Exercises) Unit will search for specific training frequencies entered by the operator Unit can also SCAN a group of training frequencies EMERGENCY frequencies are ignored when in the training mode. Two Pre-Flight checklist have been developed for use with the DF-517. EMERGENCY MODE CHECKLIST (for actual SAR missions) TRAINING MODE CHECKLIST (for training missions) USE YOUR CHECKLIST!

Selecting Operation Mode 1) Turn ON by pressing ON/OFF 2) Select EMERGENCY or TRAINING mode by rotating PAGE knob. 3) Verify desired mode is selected. Note: Unit will automatically timeout and go to PAGE 1. You must select the operational mode before this timeout occurs. It will be necessary to turn the unit OFF and then ON again if the timeout occurs before you select the desired mode.. Indicates unit software version Serial number of control-display

SAR–DF 517 Direction Finder Power-On and Operation Mode Basic operation of the DF-517 is the same in either the EMERGENCY MODE or TRAINING MODE. Pre-Flight settings however are different! Emergency-mode with fixed preselected emergency frequencies 156.800 MHz (Ch16/seaband) 121.500 MHz (VHF) 243.000 MHz (UHF) 406.025 MHz (CP/Sarsat) Training-mode with freely adjustable training frequencies (1) [156 ... 158] MHz (2) [118 ... 123] MHz (3) [240 ... 246] MHz (4) [400 ... 410] MHz

Operations Common To Both Emergency Mode & Training Mode The following slides will discuss basic operations that are common to both EMERGENCY mode and TRAINING mode operations. There are 6 viewing PAGES that may be selected by turning the PAGE control in the upper right corner of the control-display unit. PAGES 1-3 display the RELATIVE BEARING of the ELT signal. The method used to display the bearing on the DF-517 is similar to (but not exactly the same) as how a relative bearing is displayed on an ADF indicator. It is very important to realize that this is a RELATIVE BEARING that is relative to the nose of the aircraft, NOT the heading to be flown. PAGES 4-6 display the COSPAS/SARSAT signal decoding information and allow the flight crew to make changes to units operational settings.

SAR–DF 517 Direction Finder Page Selection and Dimming Turn the PAGE knob to select the desired page. Page [1 ... 3]: Relative Bearing Pages Page 4: Cospas/Sarsat Message decoding Page 5: Edit menu Page 6: Adjustable Training Frequencies Dimming Is executed in an exponential curve, allowing very accurate adjusting of display brightness under night and/or NVG conditions. Adjustments are made by pressing down the REP button while turning the PAGE knob.

SAR–DF 517 Direction Finder (Pages 1, 2, 3) Pages 1, 2 and 3 are used during flight to locate the ELT. The function knobs on the face of the control-display work identically for each page. Notice this display is set to PAGE 1 as shown in the upper right corner of the control-display

SAR–DF 517 Direction Finder Bearing (Pages 1, 2, 3) 360-degree view Page 2: 90 degrees view Page 3: Digital reading

Display Readings Page 1: 360°bearing Page 2: expanded 45° Page 3: bearing text (1) Relative Bearing value (2) Spread Maximum deviation of unaveraged bearing. Good bearing results even with a spread of 45°as a result of the averaging procedure. Note: as you approach near the ELT and the signal becomes very strong, the spread will narrow. (3) Receive level Field strength. Page 1 shows approx. 50%, Page 2 shows approx. 75% (4) Squelch level Squelch level must be above the noise level without a received signal. (5) Offset Corrects for antenna alignment (adjusted in the edit-menu). (6) Mounting Page 1 shows a BOTTOM mounted antenna. Page 3 shows TOP mounted. (7) LS: ---:--- Internal timer (LS meaning last signal) indicating the time since the last signal was received, displayed in min /sec

SAR–DF 517 Direction Finder SQUELCH ADJUSTMENT Proper SQUELCH adjustment is very important. The squelch is adjusted using the SQL knob. The squelch setting MUST be set slightly above the noise level. It should be set while performing the pre-flight checklist after engine start while the aircraft is still on the ground. The level of the squelch adjustment is indicated by the small arrow next to the vertical signal level bar. The DF-517 in the above example is receiving an active ELT signal level that is approximately 50% and is above the original squelch level

“Locate Target = Fly the Ball” Bearing +002° RIGHT Bearing -002° LEFT or +358° RIGHT. Bearing +006° RIGHT PAGE 1 Observer tells pilot to turn 2 degrees right to center ball at top of display. PAGE 2 Observer tells pilot to turn 2 degrees left to center ball at top of display PAGE 3 Observer tells pilot to turn 6 degrees right (no ball is displayed on Page 3). Note: How do you know when you are over your target? The “ball” will swing to the 180 degree position on PAGE 1 just after you pass over the target. When you are exactly over the target you may notice a “cone of influence” similar to passing over a VOR during which the signal may be lost momentarily before it swings to 180 degrees.

SAR–DF 517 Direction Finder FREQUENCY SELECTION The frequency is selected using the (+/-) knob in the lower right corner of the control-display. The FRENQUENCY selected is shown in the bottom right corner of the control-display. You can select individual frequencies in either the EMERGENCY or TRAINING modes. If an individual frequency is selected the unit will search only for the selected frequency. You can also select to sequentially SCAN all of the frequencies. Note: If the unit is in TRAINING mode and SCAN is selected, it will NOT search for EMERGENCY frequencies. If the unit is in EMERGENCY mode and SCAN is selected it will NOT search for TRAINING frequencies.

SAR–DF 517 Direction Finder VOLUME ADJUSTMENT The VOLUME is adjusted using the volume adjustment (+/-) knob in the lower left corner of the control-display. This will adjust the audio volume of the received signal. It is highly recommended that you also monitor the search frequency on one of your aircraft COMM radios. Note: On some aircraft the audio signal may not be available from the DF-517 control-display. In this case the volume adjustment will have no function.

SAR–DF 517 Direction Finder FUNCTION KEYS Pressing CLR will clear the last stored bearing from the units memory. It is usually not necessary to use this feature during searches. Pressing STORE will save the current bearing in the units memory. Pressing REP will recall the last bearing stored in the computers memory.

SAR–DF 517 Direction Finder COSPAS-SARSAT (Page 4) Cospas/Sarsat Signal This slide shows the details of an acutal COSPAS/SARSAT signal. Transmitted once every 50 sec (pulse is only 400 msec long) Contains a digital message (112/144 bit) Includes a country code, a specific trasmitter Hex ID code and LAT/LONG coordinates of the ELT.

Using the SCAN mode while bearing COSPAS/SARSAT signals It is recommended that you use the SCAN mode when searching for a COSPAS/SARSAT 406.025 MHz signal. This will allow the unit to also search for other emergency signals during the delay time between the 406.025 MHz signal transmissions. The COSPAS/SARSAT signal is transmitted only once every 50 sec (Pulse length of 400ms). The scanning mode is possible with frequencies 406.025 MHz, 121.500 MHz and 243.000 MHz or the matching training frequencies. The LS: ---:--- timer (LS meaning last signal) will display the time since last COSPAS/SARSAT signal. This unit is set to SCAN mode.

SAR–DF 517 Direction Finder Edit Menu (Page 5) TimeHold: Duration [sec] of internal storage of the averaged bearing value. This is normally set to 10 sec. Offset: Electronic correction (rotation) of the antenna orientation. This is normally set to +000. Do NOT make changes to the Offset value unless you have received training on how to set this value. Mounting: Type of Antenna Mounting (Top/Bottom) Very Important! Ext. Dimm: Range of voltage to control the dimming of the display VERY IMPORTANT. The antenna Mounting MUST be correct. Top means the antenna is mounted on the TOP of the aircraft facing up. Bottom means it is mounted on the BOTTOM of the aircraft facing down. Improper setting will cause bearing to 180 degrees out.

SAR–DF 517 Direction Finder Edit Menu (Page 6) Adjustable Training Frequency Ranges Adjustable Training Frequency Ranges: Seaband: [156 ... 158] MHz (Chnl 1..88 sea) Freq.1: [118 ... 123] MHz (VHF-band) Freq.2: [240 ... 246] MHz (UHF-band) Freq.3: [400 ... 410] MHz Select the frequency to be changed using the knob on the bottom left corner Change the frequency using the knob on the bottom right corner. Then press STORE to save changes. Typical training frequency is 121.775 MHz.

! USE THE PREFLIGHT CHECKLIST !

EMERGENCY MODE CHECKLIST (7) (3) (2) (4) (6) (1) (5) Turn ON Select EMERGENCY Select PAGE 1 Verify Correct Antenna Mounting Turn Volume ON Select EMERGENCY Frequency or SCAN mode. SET SQUELCH LEVEL ! (Set just above noise level. This example is a little too high.)

TRAINING MODE CHECKLIST (6) (3) (11) (7) (2) (8) (4) (5) (10) (1) (9) Turn ON Select TRAINING Select PAGE 6 Select Training Frequency Band Set/Verify Training Frequency. Change only if needed. Press STORE button to save any changes made to training frequency. Not necessary if no changes made. Select PAGE 1 Verify Antenna Mounting Turn Volume ON Select Training Frequency or SCAN mode. 11) SET SQUELCH LEVEL ! (Set just above noise level. This example is a little too high.)

SOME FINAL NOTES SQUELCH Adjustment. It takes some practice to learn the correct setting of the squelch control. If the squelch is set to high, you may not be able to receive the ELT signal. If the squelch is set to low (in the noise level) you will receive erroneous ELT signals that may tend to “bounce” around the screen. Don’t be afraid to play with the squelch adjustment while in flight. You will quickly learn how to tell the difference between a valid ELT signal and an erroneous signal cause by noise. Be sure to monitor your COMM radio also. Listen for the characteristic ELT “whooping” signal on the correct frequency (usually 121.5 MHz for EMERGENCIES or 121.775 for TRAINING). If you can hear the ELT on your COMM radio, but it is not being indicated on the DF-517, your squelch setting is probably too high. The PILOT should not be watching the DF-517 display. The OBSERVER should be watching the display and giving bearing directions to the pilot. The pilot’s job is to provide the crew a safe flight environment. FLY SAFE! Proper training and practice using the DF-517 will SAVE LIVES!

SAR–DF 517 Direction Finder Error Messages Error, location Reason Error 10 E10:VOLT/D Main voltage supply Voltage input too low (10.0V) Error 9 E9:NO DATA Connecting cable:antenna  display or Display-Unit No or damaged connection between antenna and display, or damaged display-unit Error 8 E8:BAD/ANT Connecting cable: antenna  display Incompatibility of antenna and display resp. bad connection of display and antenna. Error 7 E7:BAD/DIS Display Incompatibility of antenna and display Error 6 E6:VOLT/A antenna Voltage supply at antenna unit too low (9.0 V). Main voltage supply too low or considerable drop of voltage between display and antenna. Error 5 E5:OSCILAT error in synthesizer-oscillator of receiver in antenna-unit. Error 4 E4:F/+OFS+ received transmitter Received frequency too high (more than 6 KHz / error of transmitter Error 3 E3:F/-OFS- received frequency too low (more than 6KHZ / error of transmitter) Error 2 E2:CS/SYNC radio distance: transmitter  DF Synchronising bits of Cospas/Sarsat signal (bit 1 to 24) defective Error 1 E1:CS/BCH1 Error of data bits in 1st Cospas/Sarsat data block PDF1/BCH1 Error 0 E0:CS/BCH2 Error of data bits in 2nd Cospas/Sarsat data block PDF2/BCH2 Exit