Direction Finders
Locator Beacons
Emergency Receivers
Multi-Band Direction Finder System for Airborne SAR



The RT-600 (SAR-DF 517) is an SAR direction finder system for airborne SAR that operates on all frequency bands used for rescue missions, including emergency frequencies 121.500 MHz, 243.000 MHz and 406.028 MHz (Cospas-Sarsat) as well as channel 16 of the marine band. Emergency beacons that operate on the Cospas-Sarsat frequency 406.028 MHz can be identified and localized. No additional equipment is required in the aircraft since the electronic direction finding components are integrated into the antenna. The display and control unit consists of an 80-mm round instrument, and the graphic LCD display permits convenient viewing of localization and Cospas-Sarsat information.


This high-precision SAR direction finder system was designed specifically for use on board of all aircraft, including helicopters.

Special Features

  • Universal SAR direction finder: VHF aviation and marine band, UHF aviation band, Cospas-Sarsat frequency
  • High reception sensitivity to permit detection of extremely weak or distant signals
  • High direction finder accuracy, precise and stable display
  • Optimized for use on board aircraft: compact display and control unit with LCD display


Method of bearing Doppler-principle (3kHz rotational frequency, right / left rotation)
Bearing accuracy ± 5°
Internal resolution
Sensitivity RF-Voltage at Receiver Input (50Ohms) VHF<100nV; SeaBand<100nV; UHF<100nV; 406MHz<150nV
Frequency stability ±2.0 ppm (Δf/f=±2·10-6) [ at Temperature range -30°C...+80°C]
Receiving channels 8 (four of them are free adjustable)
Receiving frequencies (or see type plate for special customer options)
Emergency mode Trainings mode
121.500 MHz (VHF) [118.000 ... 122.975] MHz
156.800 MHz (maritime, channel 16) [156.000 ... 161.975] MHz
243.000 MHz (UHF) [240.000 ... 245.975] MHz
406.025 MHz (Cospas/Sarsat) [400,000 ... 409,975] MHz
Scanning mode When receiving Cospas/Sarsat signals, the emergency frequencies 121,500 MHz and 243,000 MHz may be surveilled simultaneously.
Cospas/Sarsat analysis Reception and analysis/decoding of Cospas/Sarsat data signal (112 resp. 144 bit, 400 baud, biphase L-phase modulated, with Bose-Chaudhuri-Hocquenghem error test / specified according Cospas/Sarsat C/S T.001 October 1999)
Bearable kinds of modulation A3E, F3E, A3X (ELT-modulation); bearing mostly independent of modulation
Polarisation Vertical
Error of polarisation ≤ 5° at 60° field vector rotation
Garbling cone app. 30° to the vertical
Time of response ≤ 50 ms (with sufficient receiving field strength)
LC-graphic display 128x64 dots, supertwist /transflective, extended range of temperature, dark-blue display on yellow-green background, lit up.
Free adjustable (exponentiell) dimming of brightness
Supply voltage range 12 V ... 35 V DC
Current consumption LCD-background lighting Off: max. 350 mA (12 V DC) / 200 mA (24 V DC)
LCD-background lighting 100%: max. 600 mA (12 V DC) / 300 mA (24 V DC)
Interface External connections (optional / at Sub-D 9pol. connector X4 male)
Pin 8
external voltage for variable dimming
Analog input signal for variable controlling of the LCD-background and legends illumination. Input voltage free adjustable in the range of [1.5…33]V at edit menu (Display Control Unit Page 5). Look chapter edit menu.
Default setting [10…28]V. (10V=Off, 28V=max. dimming) Impedance of input > 50 kΩ
Pin 6
night status line

Low-active. At input voltage < 2.5V the dimming operates in night mode. Max. of brightness ca. 2% of day/default mode impedance of input > 50 kΩ
Only at SAR-DF 517 N with NVG frontpanel, otherwise do not use.

Pin 4
NVG Status Line

Low-active. At input voltage < 2,5V the dimming operates in NVG mode. Max. of brightness ca. 2% of day/default mode Impedance of input > 50 kΩ

only at SAR-DF 517 N with NVG frontpanel, otherwise don’t connect.

Pin 7
Audio output signal

AC coupled voltage source with very low inner resistance.
Max. output voltage app. 8Vss = 2,83VRMS at Volume Max.
Max. output power ca. 2W with 4Ω speaker.

If a headphone is connected [32…600]Ω / 100mW, we recommend using a resistor (18Ω / 0,25W) between audio output and headphone to prevent damaging the headphone.

Serial interface RS232 (9600 baud, 8 databits, 1 stoppbit, no parity)
Pin 3
Serial output (ca. ±10V)
Pin 2
Serial input (ca. ±10V)
Display permissible operating temperature: -20°C ... +60°C
permissible storage temperature: -30°C ... +80°C
Antenna permissible operating temperature: -40°C ... +60°C
permissible storage temperature: -55°C ... +80°C
Protection system bearing antenna : IP 67
Weights display unit : 250 g
bearing antenna : 2000 g
Dimensions display unit: 82mm x 82mm x 43mm (width x height x depth)
bearing antenna: ∅270mm x 185mm