66 INSTALLATION AND LICENSING OF SSB RADIO

262. THE INSTALLATION OF AN SSB RADIO

There are three major components to SSB radiotelephone communication set:

(1) the control unit comprising the electronics (fig. 66-1). (2) the aerial system comprising an aerial tuning unit (ATU) and the aerial (antenna) itself, and (3) the ground-plane (or earthing) system.

Ideally, installation should be carried out by a marine electronics specialist but DIY installation is feasible provided particular attention is paid to the power, aerial and earth systems.

Since the purpose of the transmitter is to convert direct current (DC) energy to radio frequency (RF) energy, power input is crucial to the success of an SSB set.  Most small craft SSB transceivers operate from a 12-volt system.  This ’12volts’ is only a nominal figure – it could be anything from 11 volts to 15 volts depending on the state of charge of the battery.  Manufacturers usually make their equipment capable of accepting 11-15v without damage but radio transmitters which are particularly sensitive to input voltage changes will only give their quoted output for a specific (normally 13.6v) input voltage.  The output will fall dramatically for even a small reduction in input voltage.  For this reason the battery charger (engine or generator) should be kept running all the time the transmitter is in operation.

Note particularly that the 13.6v is at the input terminals of the set.  To avoid unacceptable voltage drop, the supply lead from the battery should be very heavy cable.  If a power lead (or ‘cord’) is supplied it is not intended to be extended.  For best results the battery should be placed so as to allow very short cables to the transmitter.  With some sets the controls may be in a unit separate from the transceiver and more convenient for operation.

All modern electronic equipment radiates electromagnetic waves and is affected by them.  The recent rapid proliferation of marine electronic equipment working in close proximity to other electronic equipment has created real problems which the European Union is currently addressing with a view to introducing standards of electromagnetic compatibility (EMC) in the marine environment.

For the aerial system most sailboat owners elect to use a backstay (insulated at top and bottom) or a hoisted plastic-covered copper wire for an antenna, either of which is inexpensive, avoids wind resistance and what some would consider the unsightliness of a long whip aerial.  If a dismasting occurs, however, the antenna will be lost just when it is most likely to be in demand, so a spare whip antenna should be carried for such a contingency.

Motorboats with very short masts have little choice but to use whip aerials.  Loaded whips with spirally-wound wire to accommodate greater length, are more efficient on the VHF and lower HF bands.

An ATU (aerial tuning unit, sometimes called an automatic antenna coupler) – (see fig. 66-3) is always necessary to tune up an insulated backstay or hoisted wire.  There is no magic length of antenna for any particular frequency the coupler will electrically lengthen or shorten the backstay or hoisted wire.  The usual antenna coupler is a solid state weatherproof instrument which mounts out of the way beneath the antenna system (usually in the lazarette) and may cost between £400 and £1000.

Fair results are obtained from couplers at the cheap end of this range, but for £600 to £1000 a microprocessor-controlled coupler will achieve the best possible match to squeeze the last watt of power out of the transmitter and into the antenna system.  Top-of-the-line couplers have almost unlimited frequency capability.

Regarding the earthing system it should be remembered the antenna is merely the radiating portion of the entire antenna system and it requires a mirror image of itself before it will send out an SSB signal.  This mirror image, called a counterpoise, is created by using the seawater as a ground-plane.  Installing an adequate antenna and grounding system for MF and HF SSB radio is not simple and owners would be well advised to get professional advice beforehand and to employ a licensed technician to undertake the installation work.

 (The whip antenna shown here would be installed if a dismasting were to occur).

The ground-plane system begins directly below the antenna coupler and consists of between 60 and 100 sq. ft (5.6 to 9.3 square metres) of metal surface area.  The ground system does not actually need to contact the seawater to be effective.  An encapsulated lead keel, for example, makes a ‘capacitive’ ground by virtue of its proximity to the seawater.  A suggested sailboat ground-plane system is illustrated in fig. 66-4.

263. THE LICENSING OF SSB RADIOTELEPHONES AND OPERATORS

A vessel must be licensed for R/T installation and in the case of an SSB radio must also include a VHF installation.  If the latter has been previously installed the vessel should already possess a Ship licence but this will have to be updated if the SSB set is added at a later date.

Applications for a Ship Licence for vessels sailing under the British flag should be made to the: –

Department of Trade and Industry, Marine Licensing Section, Radio Regulatory Division,

Waterloo Bridge House, Waterloo Road

LONDON, SE1 8UA.

A Ship Licence, for which a fee is payable, must be renewed annually.  It is a condition of the licence that the set complies with certain performance specifications laid down by the government, and an official will visit the craft to inspect the radio installation and to ensure that the conditions of the Licence have been met.

A call-sign will be allotted to the yacht (if not already allotted) and the Licence shows the name and callsign of the yacht, the frequencies, power for transmission, the type of emission and the conditions under which the station must be operated.  Penalties for contravention of these Licence terms include a heavy fine and even imprisonment.

Radiotelephone operator’s certificates, which are valid for life, are awarded on successful completion of an examination for which a fee is payable.  In the UK the relevant certificate is called the Restricted Certificate of Competence.  The term ‘restricted’ simply means that the operator is restricted to using approved marine (not aeronautical or amateur) transmitters which will operate only on preset marine frequencies.  Enquiries for operator’s certificates for MF and HF SSB radio’ should be made to the Examination Duty, Maritime Radio Services, British Telecom International, 43 Bartholomew Close, London, ECLA 7HP.

Both the Ship’s Licence and the operator’s Certificate must be available for inspection by an authorised officer of the government at any port of call (UK or overseas).  British yachts are given an annual licence disc for display in cabin or wheelhouse window.

Although a vessel must be licensed for R/T installation and the set must always be controlled by a certificated operator, anyone may use the set provided this is done under the supervision of the authorised operator, who is responsible for ensuring that the correct frequencies are used and that the proper radiotelephone procedures are followed.