1
Frequencies and Classes of
Emission
1.1 The transmitter should be capable of transmitting
on all frequencies allocated to the maritime mobile service in the
frequency band 1,605 kHz to 27,500 kHz. As a minimum, the following
frequencies should be readily accessible to the operator: the voice
frequencies 2,182, 4,125, 6,215, 8,291, 12,290 and 16,420 kHz; the
NBDP frequencies 2,174.5, 4,177.5, 6,268, 8,376.5, 12,520 and 16,695
kHz; and the DSC frequencies 2,187.5, 4,207.5, 6,312, 8,414.5, 12,577
and 16,804.5 kHz.
1.2 Radiotelephone frequencies are designated
in terms of the carrier frequency; NBDP and DSC frequencies are designated
in terms of the assigned (centre) frequency. When NBDP and DSC signals
are transmitted using a transmitter in the J2B mode the (suppressed)
carrier frequency should be adjusted so as to have the NBDP and the
DSC signal transmitted on the assigned frequency. The selected transmitter
frequency should be clearly identifiable on the control panel of the
equipment.
1.3 The transmitter should be capable of transmitting
(upper side band signals, where appropriate) using classes of emission
J3E, H3E and either J2B or F1B.
1.3.1 When switching to the preset distress frequency
2,182 kHz, the appropriate class of emission in accordance with the
Radio Regulations should be selected automatically.footnote
1.3.2 When switching to the assigned (centre)
frequencies for NBDP and DSC specified in 1.1 above, classes of emission
F1B or J2B should be selected automatically.footnote
1.4 It should be possible to change the transmitter
from any class of emission to another for which it is designed to
operate by means of not more than one control.
1.5 It should be possible for the user to select
transmission frequencies independent of any receiver setting. This
does not preclude the use of transceivers.
1.6 It should be possible to change the transmitter
quickly from operation on any frequency to operation on any other
frequency, and in any event within a period not exceeding 15 s. The
equipment should not be able to transmit during channel switching
operations.
1.7 Means should be provided to prevent overmodulation
automatically.
2
Frequency Accuracy and Stability
The transmitter frequency should remain within 10 Hz of
the required frequency at all times following the warming-up period.
3.1 During normal modulation, the peak envelope
power in the case of J3E or H3E emissions, or the mean power in the
case of J2B or F1B emissions, should be at least 60 Wfootnote at any frequency within the specified
frequency range.
3.2 if the rated output power exceeds 400 Wfootnote in the band, provision should be made
for reducing the output to 400 W or less. Generally, only the minimum
power necessary should be used for all radio communications.
4
Permissible Warming-up Period
The equipment should be capable of operation within 1 min
after switching on.
Continuous operation should be possible when the transmitter
is adjusted to operate at its rated power.
6
Controls and Indicators
6.1 Provision should be made for indicating the
antenna current or power delivered to the antenna. Failure of the
indicating system should not interrupt the antenna circuit.
6.2 Manually tuned equipment should be fitted
with a sufficient number of indicators to permit accurate and rapid
tuning.
6.3 Operation of the transmit/receive control
should not cause unwanted emissions.
6.4 All adjustment and controls necessary for
switching the transmitter to operate on 2,182 kHz and 2,187.5 kHz
should be clearly marked, in order that these operations may be performed
readily.
The equipment should be so designed and constructed that
when the transmitter is providing power to the antenna, the transmitter
is protected against damage resulting from disconnection of the antenna
or short-circuiting of antenna terminals. If this protection is provided
by means of a safety device, that device should automatically be reset
following removal of the antenna open-circuit or short-circuit conditions.
8.1 If it is necessary to delay the application
of voltage, for example anode voltage, to any part of the transmitter
after switching on, this delay should be provided automatically.
8.2 If the transmitter includes parts which are
required to be heated in order to operate correctly, for example crystal
ovens, the power supplies to the heating circuits should be so arranged
that they can remain operative when other supplies to or within the
equipment are switched off. If a special switch for the heating circuits
is provided, its functions should be clearly indicated; it should
normally be in the "on" position and be protected against inadvertent
operation. The correct operating temperature should be reached within
a period of 30 min after the application of power.