RHOTHETA Elektronik

RT-500-M
WIDE-BAND Radio Direction Finder

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.

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)

Method of bearing	Doppler
Bearing reference	Relative bearing \| True/magnetic bearing¹
Bearing indication	Digital and by a pointer in a wind rose
Bearing accuracy²	≤ 5° RMS
Display resolution	1°
Available frequency range	118 – 470 MHz
Reception frequency	VHF Air Band 118.000 – 124.000 MHz (Basic) 118.000 – 136.992 MHz (Option F1) VHF Marine Band 154.000 – 163.000 MHz (Basic) 137.000 – 224.995 MHz (Option F2) UHF Air Band 240.000 – 246.000 MHz (Basic) 225.000 – 399.975 MHz (Option F3) COSPAS/SARSAT 400.000 – 406.092 MHz (Basic) UHF FM-Band 406.100 – 410.000 MHz (Basic) 406.100 – 470.000 MHz (Option F4)
Bearing sensitivity Continuous signal ±5° bearing fluctuation	VHF Air Band ≤ 4 μV/m / 2,5 μV/m typical VHF Marine Band ≤ 3 μV/m / 2 μV/m typical VHF Marine Band above 174 MHz ≤ 5 μV/m / 3 μV/m typical UHF Air Band ≤ 6 μV/m / 4 μV/m typical COSPAS/SARSAT ≤ 6 μV/m / 4 μV/m typical UHF FM-Band ≤ 6 μV/m / 4 μV/m typical
Bearable kinds of modulation	A3E, F3E, A3X (distress signal modulation), Bearing largely independent of modulation
Min. signal duration	≤ 100 ms
Polarisation	Vertical
Scanning	Multiple scanning and monitoring functions available
COSPAS/SARSAT functionality	Decoding of COSPAS/SARSAT message: shows beacon ID, GPS position and whole message string (short and long) Displays direction and distance to beacon³ All 19 COSPAS/SARSAT channels available Scanning of all 19 COSPAS/SARSAT channels
TFT graphic display	5“ (127 mm), 24 bit RGB 800 × 480 × 3 dots Max. brightness: >500 cd/m²; 800 cd/m² typical Dimming: manual and automatic
Audio	Internal speaker: 1 W; 8 Ohm External speaker: 1 W; 8 Ohm Line out: adjustable from 200 mV_pp to 2 V_pp
Operating voltage	12 V to 30 V DC
Power consumption	Max. 15 W; typical 8 W; standby 7 W
Current consumption	Max. 1.5 A
Interfaces	3× NMEA 0183 (RS422) \| 3× RS232 Ethernet LAN (NMEA over LAN) Alarm relay output (1 A, 30 V DC \| 0,3 A, 125 V AC) PTT input for self-bearing suppression Squelch output for external audio controlling 2× programmable I/O ports
Standards	EN 60945; EN 60950-1; EN 60950-22; FCC Part15⁴

If heading data available
Measured with unmodulated, undisturbed wave field at field strength ≥ 20 dB above sensitivity level by changing the angle of incidence with the antenna rotating on a revolving table in order to eliminate environmental influences on the results.
If GPS information is available at NMEA interface
Other standards on request

RT-500-M

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 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.

RT-500-M