Ian Waugh - A Mariner\'s Guide to Marine Communications

SSB radio operation and controls

To get the best from your Marine MF /HF SSB Radio, you should

operate the controls shown in the schematic diagram in the manner
described below:

Choose from 1 (DSC Controller), 2 (Handset) or 3 (Computer)

depending on the type of communication required.

1 DSC Controller: Will always be the first choice alerting device before

using the handset for a Distress, Urgency or Safety Call & Message.

The DSC Controller may also be used to call other ships and coast

stations (where DSC service is available) prior to exchanging routine

communications (intership calls/link calls). The DSC Controller will

normally set your Transceiver (TxlRx) to the correct Class of Emission

and frequency, allowing you skip steps 4 and 5 below.

2 Handset: Voice communications should normally be your first choice
for Distress, Urgency and Safety communications and is normal for
routine intership conversations and link calls.

3 Computer/Telex/e-mail: Telex communications may be used for

Distress, Urgency or Safety communications when voice

communications have failed (subject to service being available ashore

and/or ships in the vicinity having telex facilities). Telex (and,

increasingly, e-mail) is used extensively for ship-shore messaging on

ship'S business. Some telex/e-mail software will, like the DSC

Controller, automatically set the Tx/Rx Class of Emission and

frequency, allowing you to skip steps 4 and 5 below.

In order to transmit/receive a voice, DSC, telex or e-mail call you

have to :

• Select a carrier frequency.


• Tell the equipment what class of emission (voice/DSC/telex) you
  want to use.
  The Modulator unit will then combine your voice/DSC/
  telex/e-mail signals with your chosen carrier frequency, using the
  class of emission selected by you. Similarly, the Demodulator will
  separate received voice/DSC/telex/e-mail signals from the received
  carrier frequency (if you have selected the correct class of emission).

4 Class of Emission: Choose J3E (SSB voice, suppressed carrier) for

all voice communications on marine working channels (including

MARINE COMMUNICATIONS 139