RT-500-M WIDE-BAND Radio Direction Finder of RHOTHETA

The RT-500-M operates between 118 and 470 MHz, including COSPAS-SARSAT (CP-SS) and all other V-UHF international distress frequencies. MOB-functionality for crew safety is a standard feature. Extended V-UHF air bands support cooperation with civil and military airborne forces, and the extended UHF FM band covers LMR, PMR and LPD radio frequencies, often used by smugglers and pirates. Scan functions allow creating a scan list, scan all 19 CP-SS channels, or scan multiple SAR frequencies sequentially (CP-SS…121.5…243.0). Additionally it decodes CP-SS data from an emergency beacon and thereby displays the beacon’s ID, its latitude-longitude location, as well as direction and distance to the beacon.

The RT-500-M calculates the bearing to an incoming radio signal with an accuracy of 5° RMS. Standard serial, NMEA, and Ethernet interfaces allow integration with ECDIS systems, sharing DF bearing and location data in real time. The installation of the light weight compact antenna (AU) system requires no RF cables. A distance of 100 m between AU and Display Control Unit (DCU) is no problem.

The RT-500-M direction finding system is ideal for SAR, Coast Guard, and Law Enforcement organizations, easy to install on any size of vessel and practically maintenance free.

All features at glance

• Wide-band radio direction finder‚ 118 to 470 MHz

• Numerous scan functions (COSPAS-SARSAT-Scan, SAR-Scan, Creation of scan lists, Creation of frequency exclude lists, Automatic creation of hit lists)

• MOB function: Saves the current position when pressing the MOB button and then displays the direction and distance to that position.

• High reception sensitivity to permit detection of extremely weak and distant signals

• Designed for use under very rough conditions at sea (IP 67 protection)

• Easy installation, no RF cables required

• Compact wide-band antenna system (Patent DE 4421759 C1)

• 3x NMEA, RS-422 and RS-232 interfaces for system integration and remote control

• DF of all 19 COSPAS-SARSAT channels

• Decode of COSPAS-SARSAT messages

• Storage of several COSPAS-SARSAT messages

• Shows direction and distance to GPS-position of COSPAS-SARSAT beacons

• VHF Air band in 8.33 kHz steps available

• UHF band including frequencies of SRD/LPD and PMR devices (used by pirates and smugglers)

Technical Data

Method of bearing	Doppler-principle (3 kHz rotational frequency)
Bearing Indication	Relative bearing and True/ Magnetic bearing (if ext. heading data available)
Bearing accuracy	≤ 5° (RMS)
Resolution	1°
Frequency stability	±2.0 ppm
Basic Frequency range	VHF air band: 118.000 to 124.000 MHz VHF marine band: 154.000 to 163.000 MHz (Channel 0 to 88, Sea & Coast) UHF air band: 240.000 to 246.000 MHz Cospas/Sarsat: 400.000 to 406.092 MHz UHF-FM Band: 406.100 to 410,000MHz Frequency extensions possible see below in Accessories
Frequency Options	F1 VHF-Airband: 118.000 – 136.992 MHz F2 VHF-Marineband: 137.000 – 224.995 MHz F3 UHF-Airband: 225.000 – 399.975 MHz F4 UHF-FM Band: 406.100 – 470.000 MHz
Channel spacig	VHF Air Band: 8.33 kHz VHF Marine Band: 5/25 kHz UHF Air Band: 25 kHz COSPAS-SARSAT: 8.33 kHz UHF FM-Band: 5 kHz
Scanning / Monitoring mode	Monitoring: While normal operating, 4 additional frequencies will be surveilled. (Emergency frequencies 121.500; 243.000 and two free selectable frequencies) Standby: In Standby mode the emergency frequencies, the Cospas/Sarsat and one free selectable frequency is always surveilled.
Selectiv Squelch	Trigges an alarm only if a emergency signal is detected. (to avoid fails alarms)
Cospas/Sarsat analysis	Reception and analysis 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) Indication of datacontent (mode, country, GPS-coordinates)
Bearable modulation types	A3E, F3E, A3X (ELT-modulation) bearing largely independent of modulation
Polarisation	Vertical
Error of polarisation	≤ 5° at 60° field vector rotation
Time of response	≤ 50 ms typ. (with sufficient receiving field strength)
Keyboard	Foil on the front with integrated keyboard-matrix and EL-background illumination
TFT graphic display	320 x 240 pixel with max brightness of app. 450 cd/m², continuously variable brightness
Operating voltage	12 V to 30 V DC
Rated current	2.5 A
Audio	External Speaker 4W (4 Ohm, 8 Ohm ) Line Out (adjustable from 100 mV_pp to 2000 mV_pp)
Data Interfaces	NMEA IBus (RS422 and RS232) Secondary DCU (RJ-45)
Weight	DCU: app. 1200 g (2.7 lbs) AU: app. 5200 g (11.7 lbs)
Operating temperature	DCU: -20°C to +60°C AU: -40°C to +60°C
Ingress Protection	IP 67
Bearing sensitivity VHF Airband	≤ 4 µV/m / 2,5 µV/m typical at ±5° bearing fluctuation
Bearing sensitivity VHF Marineband	≤ 3 µV/m / 2 µV/m typical at ±5° bearing fluctuation
Bearing sensitivity UHF Airband	≤ 6 µV/m / 4 µV/m typical at ±5° bearing fluctuation
Bearing sensitivity COSPAS-SARSAT	≤ 6 µV/m / 4 µV/m typical at ±5° bearing fluctuation
Bearing sensitivity UHF FM-Band	≤ 6 µV/m / 4 µV/m typical at ±5° bearing fluctuation

Accessories

Optional Frequency extensions

F1 VHF-Airband: 118.000 – 136.992 MHz
F2 VHF-Marineband: 137.000 – 224.995 MHz
F3 UHF-Airband: 225.000 – 399.975 MHz
F4 UHF-FM Band: 406.100 – 470.000 MHz

The Optional Frequency extensions can be ordered seperatly to extend the frequency range of each system individually.

DC/DC Converter

The DC/DC converter prevents damage to the direction finding system due to voltage spikes generated when starting the engines.

Antenna Measurement Device

The ram tester offers every integrator / installer the ideal tool to check the function of the RT-500-M direction finder.

Optional channel scan function F5

Extension F5 add´s a fast channel scan (within a maximum of 2 sec) to the device. Up to eight freely selectable frequencies / channels can be programmed in one scan cycle.