MF-HF Equip. and Comms:
MF-HF Equip. and Comms:
MF-HF Panel Controls
Which modes could be selected to receive vessel traffic lists from high seas coast radio stations:
Which modes could be selected to receive vessel traffic lists from high seas coast radio stations:
SSB and FEC
The SSB, single side band, radio waves focuses the effective radiation power on a part of the full wave (LSB and carrier frequencies are suppressed). Thus, the propagation can reach farther.
FEC, or the forward error correction, allows for a single transceiver to contact either one or many stations. When a message is sent, some additional data is sent that helps to catch some transmission errors. This helps with message accuracy.
Both A and D are not as effective in long-distance communication. Choice C has only two types of error detection and correction methods.
Please see Marine Insight web site, for the article What are SSB Radios?
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MF/HF Transceiver Power levels should be set:
FCC guides to use the minimum amount of effective radiating power to achieve successful communication. That is for all frequency range bands. It helps to avoid congestion of the airwaves.
As example, please view this:
FCC guidelines for reducing power of AM at night
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Which statement regarding GMDSS MF/HF Transceiver frequency set-up is true:
For set-ups, best to follow manufacturer's instructions and defined functions instead of manual entries to select channels.
Very useful manufacturer's operating manual
Example of manufacturer's info
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Which statement regarding GMDSS MF/HF Transceiver frequency set-up is true:
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To set-up the MF/HF Transceiver for a TELEX call to a coast station, the operator must:
From ITU-R M.493-01 Recommendation
DSC system for Maritime Mobile Service
"1.3 The classes of emission, frequency shifts and modulation rates are as follows:
1.3.1 F1B or J2B 170 Hz and 100 Bd for use on HF and MF channels. When frequency-shift keying is effected by applying audio signals to the input of single-sideband transmitters (J2B), the centre of the audio-frequency spectrum offered to the transmitter is 1 700 Hz."
For example of Radio Telex operating manual setup, see:
For the table of classes of emissions § 80.207, see
Code of Federal Regulations Title 47 Telecommunications
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To set-up the MF/HF Transceiver for a voice call to a coast station, the operator must:
The J3E mode facilitates transmission of information through the use of a single-side band in telephony or telegraphy.
For ITU use of J3E emissions for distress and safety purposes, see: ITU use of J3E
For the ITU's listing of modes of emissions for radio communication, see ITU Table of Emission Classes in pdf
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