The RT-300 is an all-purpose direction finder system that is designed for operation on two different frequency bands depending on the application. The RT-300 sets new benchmarks in terms of precision and reception sensitivity. Special algorithms permit fast, stable display of information.

Special Features

• Universal dual-band direction finder system for the VHF marine and aviation bands and the VHF/UHF aviation bands
• SAR direction finder, communication direction finder and navigation aid
• Automatic monitoring of emergency frequency 121.500 MHz during work on marine radio band
• Unsurpassed reception sensitivity in this class to permit detection of extremely weak or distant signals
• Selective Squelch to avoid false Alarms
• Display of bearing with reference direction as true north, magnetic north or relative
• Completely illuminated control unit
• Optimized signal processing for fast, stable direction finding
• Excellent localization precision
• NMEA, RS-485 and RS-232 interfaces for system integration and remote control capability
• Correction of lag error after changes in direction by attaching a Compass modul
• Optimized for use at sea: robust, compact design, waterproof (IP67)

Technical Data

Method of bearing

Doppler-principle (3 kHz rotational frequency)

Bearing accuracy

≤ 5° (RMS)

Bearing reference

Relative to antenna orientation, magnetic or geographic north (with optional Compass modul or external Compass Information)


LED Display: 10°
LCD Display: 1°
Data Interface: 1°

Bearing Sensitivity Airband

0,7 µV/m (typical) at ±5° bearing fluctuation

Frequency range RT-300 VS:

VHF air band: 118.800 to 124.000 MHz
VHF marine band: 156.000 to 162.300 MHz (maritime, channel 01 - 88)

Frequency steps

25 kHz

Bearable modulation types

A3E, F3E, A3X (Distress signal-modulation); bearing largely independent of modulation



Error of polarisation

≤ 5° at 60° field vector rotation

Time of response

≤ 300 ms typ. (with sufficient receiving field strength)


LC-graphic display 98x32 dots with backlight
13 buttons with legend illumination
36 LED circle for bearing display
Free adjustable dimming of LCD backlight, legend illumination and LED circle illumination

Supply voltage range

12 V to 28 V DC

Current consumption

supply voltage of 12V = stand by 350mA (4.2 W)
supply voltage of 28V = stand by 250mA (7.0 W)
typ. without ext. speaker 400mA (4.8 W) 300mA (8.4 W)
typ. with ext. speaker 600mA (7.2 W) 400mA (11.2 W)
max. without ext. speaker 450mA (5.4 W) 350mA (9.8 W)
max. with ext. speaker 800mA (9.6 W) 600 mA (16,8 W)

External audio

max. 1.5 W at 4 Ohm (Upp-max = 10 V)

Data Interface

Remote Control: RS232, RS485
Self-bearing Suppression: Discrete PTT Input
Alarm Output: Discret/optional


DCU: app. 700 g
AU: app. 1400 g

Temperature range

DCU: - 20°C to + 60°C
AU: - 40°C to + 60°C

Protective systems

DCU: IP 67
AU: IP 67

Bearing Sensitivity Marineband

2 µV/m (typical) at ±5° bearing fluctuation

Frequency range RT-300 VU

VHF air band:118.800 to 124.000 MHz
UHF air band: 241.000 to 245.000 MHz


Display (length x width x height): 220 mm x 113 mm x 27,8 mm
Antenna (Diameter x height): 260 mm x 600 mm


Constant wind speed, without ice load
150 km/h ca. 115 N
180 km/h ca. 165 N
Constant wind speed, with ice load
150 km/h ca. 150 N
180 km/h ca. 215 N


Kompass Modul

Full width hon komp modul

The compass module allows a direction indication with a northbound reference direction. By using the compass module, the so-called drag error is negated and the direction finding system responds without delay to a change of heading of the vessel.

DC/DC Converter

Full width rt 8954 hp 3

The DC / DC converter prevents damage to the direction finding system due to compensation current which flows across the System Ground to minus voltage supply e.g. generated when starting the engines. Mandatory for vessles with metal hull.


Search and Rescue (SAR)

Thumb sar bu hne 1140x350


Thumb maritime navigation 1140x350

Monitoring Communication

Thumb maritim funkverkehru%cc%88 1140x350


Thumb maritim forschung 1140x350


Thumb offshore bu hne 1140x350


KNRM Netherlands

Thumb knrm referenz


Thumb rnli referenz bild 2