What sequence best describes an MF-HF DSC Distress menu transmission?

(A). A string of dots to stop the DSC scanner, Distress priority code, vessel position & time, emission for follow-on communications, DSC frequency.

From Code of Federal Regulations, see the articles at § 80.1113 Transmission of a distress alert.

47 CFR 80.1113(a) The distress alert must identify the station in distress and its position. The distress alert may also contain information regarding the nature of the distress, the type of assistance required, the course and speed of the mobile unit, the time that this information was recorded and any other information which might facilitate rescue.

47 CFR 80.1113(b) The format of distress calls and distress messages must be in accordance with ITU-R M.493-13 and ITU-R M.541-9 (both incorporated by reference, see § 80.7), as specified in § 80.1101.

Per US Coast Guard, guidance is provided by article on Transmission of DSC Distress Alert

1. Calibrate the transmitter to either MF 2187.5 kHz or VHF Channel 70, to send a DSC distress call.
   
2. Provide info regarding:
     - the nature of distress
     - ship's last known latitude and longitude
     - UTC time when the location was known
     - Mode of further communication, such as   telephony
   

Prepare for future communications using distress traffic channel either 2182 kHz on MF, channel 16 on VHF, and wait for the DSC distress acknowledgment.

Last edited by markadlerdallas. Register to edit

Tags: none

MF-HF DSC alerts are transmitted using what emission type?

(A). J2B to ensure compatibility with DSC receivers.

The Emissions Designator J2B stands for radio signal that is transferring data using Digital format and a modulated wave.

The J2B is used for DSC and NB-DP 14 types of emissions.
For more information, see Code of Federal Regulations, article on § 80.207 Classes of emission.

Last edited by markadlerdallas. Register to edit

Tags: none

When sending a DSC call:

(B). Vessel's position will automatically be sent if the vessel is sending a "Distress Hot Key" alert.

From Code of Federal Regulations, see the articles at § 80.1113 Transmission of a distress alert.

47 CFR 80.1113(a) The distress alert must identify the station in distress and its position. The distress alert may also contain information regarding the nature of the distress, the type of assistance required, the course and speed of the mobile unit, the time that this information was recorded and any other information which might facilitate rescue.

For more specifics, please see US Coast Guard article on DSC DISTRESS

Last edited by markadlerdallas. Register to edit

Tags: none

DSC transmissions are encoded:
(C). Using a ten-bit error detecting code.

For details of the 10-bit error detection code, please see Rec. ITU-R M.493-11, paragraph 1.7 and Table I, on Digital selective-calling system for use in the maritime mobile service

More on error detection and correction, please see pdf presentation from Princeton University, Detecting and Correcting Bit Errors

Last edited by markadlerdallas. Register to edit

Tags: none

DSC transmissions are received:
(C). Using digital decoding by the DSC controller.

DSC decoder transforms maritime mobile service messages through DSC, or Digital Selective Calling module. The decoder changes messages to readable format and records their content.

For full details please see, DSC decoder decodes Digital Selective Calling (DSC/VTS)

Last edited by markadlerdallas. Register to edit

Tags: none

Properly formatted MF-HF DSC transmissions can request which of the following emissions for follow on communications?

(D). J3E/H3E voice emissions

J3E: Single side band, suppressed carrier single channel , analog transmission, telephony, voice.

H3E: Single side band, full carrier single channel, analog transmission, telephony, voice.

For more information, please see US Coast Guard article on SPECIAL CONDITIONS AND PROCEDURES FOR DSC COMMUNICATION ON HF

Last edited by markadlerdallas. Register to edit

Tags: none