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

Whether it is Inmarsat-A, Inmarsat-B or Inmarsat-M/ Mini-M.

The proximity of a person to the antenna at the time of transmission

(the closer you are, the greater the hazard).

The direction of the forward beam of the antenna and characteristic

side and rear lobes.

The length of time that a person remains within the hazardous area.

An indication of the approximate radiation hazard/safe distance

for your own unit will be included in your equipment manual but, as a

guide, the minmium safe distance (in the open) for Inmarsat-B and

Inmarsat-M antennas could be in the order of:

Inmarsat-B

forward beam direction .5 metres

side/rear lobes 2 metres

side lobe

radome

antenna

Figure 8. 7

,

Inmarsat-M

2 metres

1 metre

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'OIZ"

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1,.0)' ... '" ,

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side lobe

Inmarsat-B and Inmarsat-M Antenna Radiation hazard

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Bearing in mind that you cannot see the antenna inside of the
radome, you can only be sure of the 'safe distance' directly underneath
the radome (which should normally be either a side or a rear lobe - the
antenna should not be transmiLLing in a downward direction towards the
deck).

MARINE COMMUNICATIONS 169