4
1.2
Designing the Antenna Mast
General
To facilitate servicing, construct a mast of 1500 mm in height and 60 mm in diameter. (See
page 5.) The paragraphs which follow provide guidelines for selection and construction of
the mast. Refer to the drawing at back of this manual.
Guardrail, platform
Fit the mast with a guardrail and platform (or steps), for serviceman’s safety. (In most
installations the serviceman stands on the platform while checking the radome. Thus this
distance should be secured for ease of servicing.) The guardrail should be as high as
possible for sufficient safety.
Mast strength
The mast material must be sufficiently strong to meet the
demands of the marine environment. It should satisfy the
following requirements.
•
It must be able to support radome mass plus at least
2.5 cm of ice and snow. Special consideration should
be given if the unit is operated in areas of heavy snow
or freezing temperature.
•
Mast bending moment must be able to withstand
expected maximum pitching, rolling and wind pressure.
•
To prevent resonance at low frequencies (about 5 Hz),
four stays can be fixed between the mast and the
mounting base.
Item Mass
Antenna unit mass
8 kg
±
10%
Platform, guardrail mass
Expected ice and snow
Maximum wind pressure (at wind speed 75 m/s)
1654.9 N
Mast
Mass
Bending
Moment
Wind
Pressure
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Содержание Felcom 30
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