Ground-Link Specifications


Physical Data

  • Dimensions for inside unit: 3.5"h x 8"d x 19"w (rack mountable)
  • Dimensions for outside antenna unit: 14" by 10" by 5" not including antenna
  • Antenna adds 6 feet vertical height to assembly.
  • Cable to antenna unit: Cat 5 flooded outdoor cable, up to 600 feet no effect on RF signal.
  • Lighting Protection: 15 Joules at 600 ÁSec duration
  • Temperature operating range: -20í to +50í C

Receiver and Transmitter

  • Frequency setting: Factory set 121.725 MHz or 135.075 MHz
  • Frequency stability: 2 PPM
  • Adjacent channel isolation: 80 db, prevents false keying of Ground Link
  • VA Sensitivity .12 ÁV for 10 db SN ratio
  • Squelch range: .12 ÁV to 5 ÁV not used in VA mode
  • Transmit power: 1 Watt PEP
  • Modulation: Single sideband with carrier, 80% modulation limit
  • Channel Selectivity: 8.5 kHz Audio range: 150 to 4,500 Hz

Processor and Interface Components

  • Digital Signal Processor (DSP): Analog Devices ADSP-2185L 50 MIPS
  • Control Processor: Intel 8752 Microprocessor
  • Control Program: Custom BASIC interpreter with Radio, Telephone, and Voice keywords
  • Voice Processing: Telephone based CODEC
  • Voice Coding: U-Law 8 bit coding at 8000 samples per second
  • Voice bit rate: 64,000 bit per second, toll quality speech
  • Stored Voice Format: 8000 Bytes per second of speech PCM WAV format
  • Voice Recognition: Custom DSP code based for speaker independence
  • Storage Medium: Compact Flash Storage Card
  • BASIC Program and Voice Messages: Stored on Compact Flash Card


  • Dual opposite Phased Verticals with active Phasing Module
  • Allows quasi full duplex operation on AM carrier signals
  • 60 db of isolation between TX and RX antenna ports
  • 2.5 dbd gain on antenna system
  • Antenna has 1.5 Degree down tilt to limit airborne coverage per FCC specifications

Telephone Interface

  • Dialing: Pulse or Tone
  • Call Progress: Ring, Busy, Fast Busy, Dial Tone
  • Answer Supervision: Line Current, or Voice detection
  • Auto Announce: Speaks preset message to Telephone line on Answer Telephone
  • Line Detection: Ring and Loop Current Detection
  • Telephone Frequency range: 300 to 3000 Hz
  • Lighting Protection: 5 Joules at 600 ÁSec duration

Programming Features

  • BASIC program allows custom scripts for each end user Interactive operation with pilot using Voice Activation and Menu options
  • Supports Answers with two Key clicks of Pilot Transmitter
  • Support Voiced Yes, No, commands
  • Abort of Basic Program with Multiple Transmit keying to Reset Ground Link