What is the fundamental purpose for imposing radio silence?

(D). To mitigate the risk of interference on a frequency or channel being used for emergency communications.

FCC guides for all transmissions to listen first (in silence) before initiating a radio wave propagation.

§ 80.325 Control of distress traffic.

47 CFR 80.325(c) The station in distress or the station in control of distress traffic may impose silence either on all stations of the mobile service in the area or on any station which interferes with the distress traffic.

See Code of Federal Regulations for § 80.325 Control of distress traffic.

Last edited by markadlerdallas. Register to edit

Tags: none

When can routine communications be resumed when radio silence has been imposed?

(A). Routine communications can resume after the Rescue Coordination Center transmits a message on the frequency or channel being used for emergency communications stating that such traffic has concluded.

§ 80.1121 Receipt and acknowledgement of distress alerts by ship stations and ship earth stations.

47 CFR 80.1121(d) In cases where distress alert continues to be received from the same source, the ship may, after consultation with the Rescue Coordination Center, transmit a DSC acknowledgment to terminate the call. Reference

Last edited by markadlerdallas. Register to edit

Tags: none

What is meant by the term "Seelonce Mayday"?

(B). Stations not directly involved with the on-going Distress communications may not transmit on the Distress frequency or channel.

47 CFR 80.325(c) The station in distress or the station in control of distress traffic may impose silence either on all stations of the mobile service in the area or on any station which interferes with the distress traffic.

47 CFR 80.1125(e)(1) In radiotelephony, the signal SEELONCE MAYDAY, pronounced as the French expression “silence, m'aider” Reference

It must address these instructions “to all stations” or to one station only, according to circumstances.

In either case, it must use one of the following signals which are reserved for use by the mobile station in distress and for the station controlling distress traffic:

(1) In radiotelegraphy, the abbreviation QRT, followed by the distress signal SOS.

(2) In radiotelephony, the signal SEELONCE MAYDAY.

See Code of Federal Regulations on § 80.325 Control of distress traffic.

Last edited by markadlerdallas. Register to edit

Tags: none

How is "radio silence" imposed?

(C). By the On Scene Coordinator (OSC) or the RCC chosen by the SAR Mission Coordinator.

§ 80.1125 Search and rescue coordinating communications.

47 CFR 80.1125(e) The Rescue Coordination Center coordinating distress traffic, the unit coordinating search and rescue operations, or the coast station involved may impose silence on stations which interfere with that traffic.

This instruction may be addressed to all stations or to one station only, according to circumstances. In either case, the following will be used:

(1) In radiotelephony, the signal SEELONCE MAYDAY, pronounced as the French expression “silence, m'aider”;

See Code of Federal Regulations, Title 47 Chapter I Subchapter D Part 80 § 80.1125 Search and rescue coordinating communications.

RCC is the Rescue Coordination Center

On Scene Coordinator (OSC)

• Executes plans, communicate with involved SAR locations, analyze other SAR's reports, and forwarding status updates with SMC. (According to IAMSAR, the SMC is the “the official temporarily assigned to coordinate response to an actual or apparent distress situation.”)
  

• informs the SMC to release unnecessary resources
  

• informs the SMC to make available additional resources<b>

According to IAMSAR ( International Aeronautical and Maritime Search and Rescue):

SAR - is a person/s or organizations that performs defined duties, while being responsible for rescue services and manages other entities to ensure coordination.

The defined duties includes, supervising, communicating with relevant parties, regarding rescue efforts, medical assistance, with assistance from available resources.

For more information, please see International Maritime Rescue Federation site, CHAPTER 19: THE SAR MISSION COORDINATOR

Last edited by markadlerdallas. Register to edit

Tags: none

How are normal working conditions restored on a SITOR (NBDP) frequency on which radio silence had been imposed?

(C). The RCC or Coast station that imposed the radio silence must transmit a SITOR (NBDP) message stating "SILENCE FINI".

§ 80.1125 Search and rescue coordinating communications.

47 CFR 80.1125(h-j) When distress traffic has ceased on frequencies which have been used for distress traffic, the Rescue Coordination Center controlling a search and rescue operation must initiate a message for transmission on these frequencies indicating that distress traffic has finished.

(i) In radiotelephony, the message referred to in paragraph (h) of this section consists of:
(1) The distress signal MAYDAY;
(2) The call “Hello all stations” or CQ (spoken as CHARLIE QUEBEC) spoken three times;
(3) The words THIS IS (or DE spoken as DELTA ECHO in the case of language difficulties);
(4) The call sign or other identification of the station sending the message;
(5) The time when the distress situation has ceased;
(6) The name and call sign of the mobile station which was in distress;
(7) The words SEELONCE FEENEE pronounced as the French words “silence fini”

(j) In direct-printing telegraphy, the message referred to in paragraph (h) of this section consists of:
(1) The distress signal MAYDAY;
(2) The call CQ;
(3) The word DE;
(4) The call sign or other identification of the station sending the message;
(5) The time when distress situation has ceased;
(6) The name and call sign of the mobile station which was in distress; and
(7) The words SILENCE FINI.

See Code of Federal Regulations on § 80.1125 Search and rescue coordinating communications.

Last edited by markadlerdallas. Register to edit

Tags: none

How are normal working conditions restored after radio silence has been imposed?

(D). The Rescue Coordination Center (RCC) that imposed the radio silence must transmit a voice message on the Distress frequency stating "SEELONCE FEENEE".

§ 80.326 Notification of resumption of normal working.

47 CFR 80.326(a)(2) n radiotelephony, this message consists of:

(i) The distress signal MAYDAY;
(ii) The call “Hello all stations”, spoken three times;
(iii) The words THIS IS;
(iv) The call sign or other identification of the station sending the message;
(v) The time of handing in of the message;
(vi) The name and call sign of the mobile station which was in distress;
(vii) The words SEELONCE FEENEE OR PRU-DONCE.

See Code of Federal Regulations for § 80.326 Notification of resumption of normal working.

Last edited by markadlerdallas. Register to edit

Tags: none