All theory about VHF radio and practical operations within the course are shown on the GMDSS VHF simulator of Simrad's RD68 VHF radio. Here are some basic information about the simulator that should be considered.

RD68 VHF radio simulator screenshot

The simulator illustrates:
  1. GMDSS VHF radio with a combined microphone and earphone (loudspeaker).
  2. Quick dial simulation of DSC alert activation and acknowledge on another vessel or CRS.
  3. Channel 16 broadcast switch. This enables us to practice on Dual Watch,Triwatch, Scan and Memory Scan facilities explained in following chapters.
  4. GPS on/off switch. This enables us to work with or without a GPS positional input to our DSC Controller.
  5. Basic information about the vessel and the VHF radio that is usually written close to the VHF radio.
Simrad's RD68 VHF radio integrates RT and DSC facilities. With some GMDSS radio installations, these two facilities may be provided with two separate equipments, that is, one for RT and the other for DSC.

The RD68 VHF is very simple to operate, with the controls falling into six groups:
  1. The rotary controls.
  2. The alphanumeric keypad.
  3. The dedicated controls, for commonly used RT functions.
  4. The four softkeys to the right of the display are multifunction keys whose function changes depending on which menu is displayed. The label showing the current function for each softkey appears on the right side of the display beside the softkey.
  5. A Distress button under a sliding cover.
  6. PTT switch on a microphone.
RD68 controls
RD68 VHF radio controls

The radio functions are split into two main modes:
  • Radio mode allows access to standard VHF radio functions.
  • DSC mode covers the DSC (Digital Selective Calling) functions.
These modes are toggled by pressing the most upper softkey (labeled DSC or
Rad on the display).

The interaction with the user of the VHF radio is both:
  • audible, for example ringing, and
  • visual through display.
The display shows information relating to both the RT and the DSC functionality.

For example, the display in the picture above is showing that VHF CH 16 has been selected (16), full power of 25 W is enabled (Hi), radio is in receiving mode (Rx).

New information is entered via the alphanumeric keypad and softkeys, for example entering position. The flashing cursor shows the position on which next entered character will be put. Backspace function that erases the last entered character and moves the flashing cursor to the left is enabled by the Arrow softkey.


An example of the display while entering position

In some functions just few characters can be entered, for example the position latitude can be only North (N) or South (S). Those characters can be entered just using softkeys.

An example of the display while entering special characters N or S

Two special keys on alphanumeric keypad are used to confirm any entered information (E key) and to cancel it (C key).
Last modified: Saturday, 25 April 2020, 7:50 PM