appended to the alert, using the clock time of your own DSC unit. In
most cases this date/time will come from the GPS receiver - but you
may have to tell your own equipment which time zone you are operating
in, and enter ship's time into the receiver.
In some 'Sailor' DSC units the time zone entry must show the
number of hours that must be added to, or subtracted from, ship's
time, to calculate UTC - not the number of hours your vessel is
ahead/behind of UTC.Routine maintenance and checks
The only checks that have to be made on the VHF radio itself are
that:
- Volume and squelch are set correctly after changing channel.
- Screen/ controls illumination is comfortable.
You will be using Ch70 (the only DSC alerting channel) for routine
calls on a daily basis and you'll be using various voice channels for
different tasks. Any problem with the radio/DSC equipment should,
therefore, be revealed during normal use. The antenna and antenna cable
should be checked at regular intervals (monthly is suggested) to see that:
- The antenna is still vertical and not damaged.
- The cable is secure, is not pulling on the connection at the base of the
antenna and the outer covering is not chafed or damaged in any way. - Connections (at the radio, through-deck connections and at the base
of the antenna - see figure 6.2) are good and remain watertight. This
will normally be a visual check only, on external connections -
through-deck and antenna - unless you suspect a problem.
Worn or damaged cable covering will allow moisture into the outer
braid of the coaxial cable, reducing transmitter performance even
when reception remains good. Dampness getting into external
connections may affect both transmission and reception.
134 THE NAUTICAL INSTITUTE