not be rejected by the receiver. The category is fixed in some receivers,
but can be rejected in others. Tend to be longer warnings than category
A and can vary considerably in content. Extreme examples are
submarine/gunnery exercises {UK stations} and yacht regattas
(Spanish stations).
J SATNAV information. This is where you will receive information
about problems with the GPS {and other satellite navigation systems}.
The two examples above {GAOl and GB22} will therefore be:
GAOl - Navigation Warning number 01 of 99 from station G.
GB22 - Gale Warning number 22 of 99 from station G.
A typical NAVTEX receiver will remember message numbers
received for a period of three days and will not keep printing-out
any repeated message received within that time. When 'logging
mode on' {see programming area above} some receivers will print
the first line of such messages with the comment 'previously
received' The exception is category D messages, which are always
numbered 00 and will always be printed, whether you have asked
for messages from that station or not - e.g. HDOO.
Routine maintenance and checks
Each day, the designated operator should check that there is enough
paper in the machine to last until the next daily check. There are no
other regular GMDSS checks required on the NAVTEX installation. If
your NAVTEX equipment is not receiving/printing the messages you
have programmed, from the programmed station and you are
comfortably in range ofthe NAVTEX station, you may have a problem
with the equipment. That is the time to run the self test. It is also a good
idea to run that test after replacing the paper roll. That way you will be
sure that the new roll is fitted the correct way round and that the paper
is good.
Antenna connections must be kept good. The coaxial cable must
not be damaged, nor pulled too tightly at the base of the antenna.
MARINE COMMUNICATIONS 185
