# Presentation: 494251

## Becker SAR DF 517 Training

## Introduction

_*Task*_*:* Become better acquainted with the Becker DF
_*Conditions*_*:* Given checklist and classroom environment with handouts
_*Standards*_*:* Implement proper DF techniques utilizing Becker DF
_*Background*_*:* Currently all new CAP aircraft from the factory will come equipped with the Becker, and over 1/5th of the national fleet already have them

## Becker SAR DF 517System Components

- Control-Display Unit (CDU)

**	**Antenna-Receiver Unit (ARU)

- Two Primary components

## Becker SAR DF-517

- The Becker SAR DF-517 is an automatic direction finder.  It supports 121.5, 243 and 406 MHz frequencies
- The DF unit will display a bearing relative to the nose of the aircraft for signals received
- There are two sets of frequencies that may be selected.  These are Emergency Mode or Training Mode frequencies
- The Emergency Mode or Training Mode can only be selected at power up

## Power Up

- If your aircraft is equipped with Mission Master it must be on for DF to operate
- On power up (1), verify Emergency or Training mode.  To change the setting, turn the page dial (2) and select the appropriate mode (3).  Note: this option is only available for the first 10 seconds of power up – then the system automatically cycles into the function selected

## Initial Setup

- The Page dial (2) is used to switch the DF-517 between the different pages
- By holding the Rep button and rotating the page dial (1) the brightness can be adjusted

## DF-517 DFing

- Select the desired frequency to DF by using the bottom right rotary dial (1) to select the desired preprogrammed frequency
- Use the volume (2) rotary dial to set the volume level
- Once the desired frequency is selected, use the SQL (3) dial to select the squelch level

## DF-517 DFing cont.

- According to the manufacturer DF signal can be heard by selecting the ADF monitor toggle on the audio panel
- This of course begs the question...”What if your aircraft is not equipped with ADF?”
- DFing is done using Page 1 or Page 2
- Page 1 displays a full circle with the signal and bearing in 360o
- Page 2 displays a 90o window with the relative bearing and signal

## DF-517 DFing cont.

- (1) The signal and relative bearing
- (3) Signal Strength
- (4) Squelch level
- Tracking frequency 406.025 in Emergency mode
- Note that to DF a signal, the squelch level must be below the maximum signal strength

**DF-517 Page 1 Display**

## DF-517 DFing cont.

- (1) Signal level and relative bearing
- (2) Position error
- Tracking Freq. 121.775 in Training Mode for CAP (not .650 as was default with original systems)

**DF-517 Page 2 Display**

## DF-517 frequencies

## DF-517 Adjusting Frequencies

- Page 6 enables you to adjust the training frequencies
**(1) **>**±Select**< rotary switch selecting the trainings-frequency (MHz/kHz)
**(2) **>**±**< rotary switch changing the frequency. Confirm the changed value by pressing pushbutton >STORE<
**(3) **>**STORE**< Pushbutton to confirm changed values

## DF-517

- The backlight is controlled by adjusting the top panel light adjustment and setting the annunciator panel switch in the “Night” position
-  Additional information on the Becker DF-517 can be found in the manual
- Link at: _http://www.becker-avionics.de/666571_C_Images/ImgProductsUSA/ProductsUSAPDF/ACF564.pdf_

## Operation

**ON/OFF**
**(2) PAGE**
**(3) MODE** Indication of the actual operation mode
**(4)**** ARU Version** Software version and serial number of antenna-receiver Unit
**(5) CDU Version** Software version and serial number of control-display Unit

**Power-On and operation modes emergency or training**

## Bearing mode (pages 1 to 3)

- Bearing mode (pages 1 to 3)

- (1) FREQUENCY Selected
- (2) VOLUME
- (3) SQL Should be above the noise level
- (4) CLR For erasing the stored bearing value
- (5) STORE While bearing an AM signal a 3 kHz sound is superimposed to the audio signal for technical reasons
- (6) REPEAT Displays the last valid bearing value with the corresponding receive level

## Display Readings

***Page 1: 360°bearing**** *

***Page 2: expanded ******90******°***

***Page 3: bearing text***

**(1) 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
**(3) Receive level** Field strength
**(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** TOP mounted or BOTTOM mounted antenna
**(7)** **LS: ---:---** Internal timer (LS meaning last signal) indicating the time since the last signal was received, displayed in min /sec

## Using the SCAN mode while        bearing COSPAS/SARSAT signals

- The COSPAS/SARSAT signal on 406,025 MHz is only transmitted every 50 sec (Pulse length of 400ms)
- The scanning mode is possible with frequencies 406,025MHz or 121,500/243,000MHz or the matching training frequencies
- The **LS: ---:---** timer (LS meaning last signal) always displays the time since last COSPAS/SARSAT signal was received in 406.025 MHz

**Frequency displayed in scanning mode****	**

## Becker Antenna

- Antenna mounted on bottom of aircraft
- Solid one piece unit
- This DF does not use wing null method

## Techniques

- Audio Panel Tip: **Hard to track what you can’t hear. **The bar on the left side of the display is a visual Squelch indicator, which **MUST BE SET BELOW THE AMBIENT NOISE LEVEL** for the unit to work. You can see this when the little triangle turns solid

- During regular operations, you can set the squelch above the ambient noise. (Which would alert you if you happen across an ELT, but otherwise not bug you with static noise)

## Techniques

- To hear the ELT access your ADF monitoring on the Comm panel
- Turn the squelch ALL the way down when actively searching
- COSPAS/SARSAT page will display ELT Lat/Long if it is a 406 ELT
- MO can enter Lat/Long in to GPS as waypoint

- When overflying the target, the marble will do a little wiggle, and then rapidly jump down to the bottom of the (360o View) display
- If the Observer recommends a sudden and steep turn to either direction, it’s *a good bet* that the wing would be pointing *right at* the target in the turn.

## Techniques

- Becker DF range is not as far as L-Tronics
- Utilize Aircraft comm radios to acquire the ELT signal – remember to have squelch pulled
- Conduct Wing Null – to get general location
- Proceed to Lat/Long of intersection of two Wing Nulls

- Once the Becker acquires the signal the Mission Observer will advise Pilot on course correction so that the bearing on the DCU is 0o or 360o
- Avoid minor corrections
- Once bearing drops off to 180o  you just flew over the ELT
- Mark location with GPS

## QUESTIONS?