RM8 Software-Defined VHF UHF High Speed Data Modem

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RM8 Software-Defined VHF UHF High Speed Data Modem

RM8 Software Defined Modem UHF VHFOffering a wide range of standards-based waveforms and protocols, the RM8
software defined modem with ALE, offers interoperable data modem and
link setup in a standalone unit for strategic and maritime data communications.

Whether point-to-point or point-to-multipoint, the RM8 can be operated as a
VHF or UHF software-defined modem, which is activated by the user with a
key selection.

Intended for operation with VHF or UHF radios with an audio bandwidth exceeding 21 kHz, the RM8 transfers data at rates of up to
96,000 bps over a standard 25 kHz VHF or UHF radio channel.

Low data rates (up to 32 kbps) use Offset QPSK and 8- PSK waveforms and are suitable for radios with a non-linear power amplifier (PA).
The very high rates use QAM and require a linear PA or can work with wideband FM or AM radios.

Adaptive equalization mitigates the effects of VHF or UHF channel multi-path. Convolutional encoding combined with soft-decision
Viterbi decoding provides forward error correction. High performance Doppler tacking allows operation at up to 250 km/h relative
speed (at 80 MHz).

Key Features

  • VHF/UHF modem operation
    • 96000 bps in 24 kHz channel
    • 48000 bps in 12 kHz channel
  • Adaptable configuration
    • Bandwidths: 24, 12, 9, 6 & 3 kHz
  • Menu-Driven control & configuration
  • Synchronous/Asynchronous DTE port
  • Ethernet LAN interface for Control
  • AC and DC Power
  • Compatible with RC66/ARQ
  • License keys unlock software

Additional Features

  • High Data Rate Modems
    • Up to 96000 bps (128-QAM)
    • Up to 76800 bps (64-QAM)
    • Up to 48000 bps (16-QAM)
  • Low Data Rate Modems
    • Up to 32000 bps (8-PSK)
    • Up to 16000 bps (QPSK)
  • Adaptive Equalization

External Interfaces 

The RM8 unit is fully controllable via the front panel as well as by the serial remote or Ethernet control interface and provides a DTE port
for synchronous and asynchronous data.

RM8 Software Defined High Speed Modem Data System
 RM8 based Synchronous V/UHF Data System


24 kHz High Rate: 96000, 76800, 64000, 48000 (Coded) 
Low Rate: 32000, 16000, 9600, 4800, 2400 (Coded)
12 kHz High Rate: 48000, 38400, 32000, 24000 (Coded) 
Low Rate: 16000, 8000, 4800, 2400, 1200 (Coded)
9 kHz High Rate: 36000, 28800, 24000, 18000 (Coded) 
Low Rate: 12000, 6000, 3600, 1800, 900 (Coded)
6 kHz High Rate: 24000, 19200, 16000, 12000 (Coded) 
Low Rate: 8000, 4000, 2400, 1200, 600 (Coded)
3 kHz High Rate: 12000, 9600, 8000, 6000 (Coded) 
Low Rate: 4000, 2000, 1200, 600, 300 (Coded)


  • Climatic:
    • Storage: -30 ˚C to +77 ˚C
    • Operation: -30 ˚C to +70 ˚C
  • Safety: CE: Low Voltage Directive (Directive 73/23/EEC as amended)
  • Safety: CE: Electromagnetic Compatibility (EMC) Directive (Directive 89/336/EEC as amended)
  • Width: 212.2 mm
  • Depth: 225.6 mm
  • Height: 41.1 mm (excl. front panel)
  • Height: 44.1 mm (incl. front panel)
Installation Compact design: The unit occupies a width less than ½ of am 1U 19” rack slot.
Presets Factory and Custom Presets


DTE (Data) Port 
RS-422 balanced, RS-423, RS-232 unbalanced., MIL-STD-188-114 (interoperable), EIA 530A compliant 
Half & Full Duplex operation, Synchronous, Standard and High-speed Async modes
Remote Control/
GPS Port
Remote Control Pins: RS-485 Multi-drop, RS-422 balanced or RS-232
Protocol: Control Protocol (RAP1 + RIPC, ASCII S5066 Annex E)
External GPS Control Pins: RS-232 (nominally input)
Data Rate: 300 to 19200 bps, 1/2 stop bits, 7/8 bit data. PPS line: RS 232/422 (NMEA) or TTL
GPS Antenna
Built-in GPS receiver: Time reference for 2G ALE Linking protection (AL-2).
Remote Control: 10/100 Base T (IEEE 802.3U compatible), embedded TCP/IP Stack
Protocol: Control Protocol (RAP1 + RIPC)
Data Port (RJ45)
IP Packet Data: 10/100 Base T (IEEE 802.3U compatible), embedded TCP/IP Stack
Protocol: Raw IP packet data.
Local Control Local control via 32x202 pixel graphical LCD display and 16-key keypad. 3 bi-colour LED indicators
Alphanumeric and digit keypad for fast data entry, 4-way navigation button
Radio Control
& Audio 
Radio Control Pins (2 channels): RS-232, up to 115200 bps, 1/2 stop bits, 7/8 bit data
Supports for various radio control protocols are built-in.
Input Audio (2 channels): 600 Ohm balanced, –20 to +10 dBm without adjustment
Output Audio (2 channels): Balanced, –40 to +10 dBm adjustable into 600 ohm load
Keyline: Non-polarized contact closure (<45 V, 200 mA).
PTT Sense Input: Pull to ground to indicate external PTT.
Aux Audio Pins: Connection of microphone for ALE voice calling
Input Audio: 600 ohm balanced, –20 to +10 dBm without adjustment or MIC input (selectable)
Output Audio: Balanced, –40 to +10 dBm adjustable into 600 ohm load

RM8 Software-defined VHF UHF Modem