DSC
VASUDEVAN PONDICHERRY PH: 91 96299 80476
1.
How
many distress frequencies are used in MF.HF DSC?
I MF frequency & 5 HF frequencies
2.
What
are those distress frequencies?
2187.5 KHZ, 4207.5 KHZ, 6312 KHZ,
8414.5 KHZ, 12577 KHZ, 16804.5 KHZ
3.
How
do you receive the alerts in MF/MF DSC?
Through SCAN receiver (Transmitting
DSC alerts through MF/HF transceiver)
4.
DSC?
Digital selective calling (It is used
to send and receive DSC alerts)
It is a primary means of alerting
device.
5.
What
are the types of alert can you send?
Undesignated distress alert
Designated distress alert
Distress relay alert to a particular
station / to all stations
Urgency alert to a particular
station/to all stations
Safety alert to (Area - all Stations)
Routine alert
Test alert
6.
Why
is DSC carried on board? (Purpose)
DSC is the primary means of alerting
device.
7.
If
DSC is failure is Distress situation. What will you do?
I can use satellite equipment to
contact RCC
8.
How
do you indentify the DSC Distress alert?
Or
How can you differentiate the DSC
Distress alert from other types of alerts?
Or
What is the difference between DSC
distress alert and other type of DSC alerts?
DSC distress alert is a continuous
alert. The intensity of sound will increase
9.
If
any one used DSC to acknowledge, what will happen?
Distress alert will be stopped
10. Who receive the DSC
distress alert?
All stations within the range of the
DSC distress frequency used
(CH 70 covers VHF range, 2187.5 KHz
covers MF range and ……)
11. When you send DSC distress
alert, from whom do you expect the response, the most?
From MRCC / CRS that is from shore
12. When do you carry out a
live test with a MRCC/CRS, on what frequency will you send Test alert?
Weekly test -- on any of HF DSC
Distress frequency (Except 2187.5 KHz)
(we have to check whether test
facility is available in that station)
13. Why don’t you carry out the
test on 2187.5 KHz?
As per the GMDSS regulations, we must
avoid testing on 2187.5 KHz as far as possible.
( also test facility is available on
HF DSC distress frequencies)
14. How do you test MF/HF DSC?
It is a weekly test
Mandatory
A live test can be carried out with a
CRS/MRCC.
We receive an automatic
acknowledgement from that CRS/MRCC
15. After the DSC test, what
will you do?
I will make the log entry
16. After the test alert, do you need to contact that CRS for
confirming the details of test?
No further communication between the
two stations involved in the test.
17. What are the daily tests?
Daily DSC test – SELF TEST (NON
RADIATION TEST)
Battery ON/OFF load check
Printer paper check
18. How do you test the DSC
daily?
Self test
It is testing the Modem
19. How do you test the VHF
DSC?
There are two methods
1.
We
can test the VHF DSC with another VHF DSC of our own vessel.
Use own vessel MMSI and
keep VHF on I Watt power output
and send the test alert.
In the other VHF DSC, we
can see our own vessel MMSI.
2.
We
can test our VHF DSC with VHF DSC of the nearby vessel. (before that, we have
to call them on VHF and get permission and proceed)
3.
Self
test – non radiation test
20. What is self test?
Testing the modem
21. Why it is called
non-radiation test?
It is not radiating power /not
transmitting
22. Why is the radiation test?
Testing with another DSC is the
radiation test (transmitting alert)
23. When you test the VHF DSC
with the OWN vessel VHF DSC, why do you keep the VHF on 1 Watt power output?
It is onboard communication
24. What is the speed of
transmission of DSC alerts?
MF/MF DSC is 100 bauds
VHF DSC is 1200 bauds
25.
What are the emissions of
MF HF DSC and VHF DSC?
MF HF DSC – J2B
VHF DSC – G2B
26. Repetition of DSC distress
alert?
3.5
to
4.5 minutes at random delay.
27. You have sent a routine DSC
alert. It has not been acknowledge. What will you do?
I will repeat after 5 minutes
28. After this repetition also,
you have not been acknowledged, what will you do?
After 15 minutes, I will repeat
29. MF/HF DSC alert duration
MF HF DSC alert duration Lasts for
about 7 seconds
VHF DSC alert duration Lasts for about
6 seconds
30. MMSI?
Maritime Mobile service Identity
Example :
SHIP STATION - 232157000
COAST STATION - 0002320018
GROUP OF SHIPS - 023201143
31. MID?
In ship MMSI
first 3 digits are the MID
Maritime
Identification Digits
MID identify the country licensing or
controlling the station
32. Continuous watch should be
maintained while at sea. What are they?
VHF DSC CH 70
MF DSC frequency 2187.5 KHz
HF DSC frequency 8417.5 KHz and
At least one other HF DSC frequency
VHF CH 13
NAVTEX – 518 KHz
SAT-C-EGC safety NET
HF MSI
VASUDEVAN PONDICHERRY PH: 91 96299 80476
33. What does the DSC call
consist?
DSC call consists of 9 sections
Dot pattern
Phasing signal
Format specifier
Address
Category
Message
End of sequence
Error check symbol
Weekly
Test of MF/HF DSC:
A LIVE TEST can be carried out with a
MRCC/CRS. We will receive an automatic reply from the MRCC/CRS.
Take the print out of that reply and
paste it in the Radio Log Book. Make a Log Entry.
On what
frequency, do you test your MF/HF DSC with a CRS?
On any of the HF DSC distress
frequencies
What
information do you receive in DSC Distress Alert?
Nature of distress
MMSI
Position
Time (time of transmission)
Telecommand (Subsequent communication)
Date and Time (received date and time0
Frequency ( on what frequency alert
transmitted)
VHF DSC
TEST
1.
SELF
TEST – NON RADIATION TEST
2.
TEST
BOTH VHF DSC of own vessel
3.
LIVE
TEST with a nearby ship/CRS
SELF TEST
of VHF DSC:
In Main Menu, SELF TEST is there. We
can do the Self Test by selecting it.
VASUDEVAN PONDICHERRY PH: 91 96299 80476
TEST ONE
VHF DSC with ANOTHER VHF DSC of OWN VESSEL:
As per GMDSS regulations, we have 2
VHF DSC onboard.
In one VHF DSC,
Put own vessel MMSI number
And-
Keep the VHF in 1 watt power output.
Send an Alert.
In the other VHF DSC, we can hear
alert sound
And
In the Display,
We can see OWN VESSEL MMSI.
TEST VHF
DSC WITH A NEARBY SHIP:
It is a weekly Test.
We can test our VHF DSC with a nearby
ship with prior request with them on VHF.
Put the nearby ship’s MMSI and send a
test alert.
(No automatic reply is available. They
will acknowledge the alert)
34. What are the DSC routine
frequencies?
35. Sea areas A1, A2, A3, &
A4
36. Acknowledgement to DSC
distress alert
37. DSC watch receiver?
In built in MF HF DSC – SCAN RECEIVER
VHF DSC – STANDBY RECEIVER
EXTRA QUESTIONS:
What is the priority will use for DSC false
alert cancellation?
NO priority
When
you send quick alert/undesignated distress alert on MF HF DSC, on what
frequency it has been sent?
2187.5 KHz
Check in DSC
LOGS – MAIN MENU – DSC LOGS –
SAT C is not working in sea area A3.
What will you do?
As per
equipment carriage requirements of GMDSS regulations, we have a duplication of
another satellite communication equipment. We can use it.
Also we have
MF HF transceiver and we use HF communication
SEA AREA A4 how will contact shore
office on TELEPHONE?
MF HF DSC –
MAIN MENU – DSC CALL – COAST STATION – PSTN CALL-
DISPLAY OF
DSC will guide you following steps
You can put
the phone number of shore office
Guard band of VHF CH 16
CH 76 and CH
75
Light house is not working while
entering in to port. What will you do?
Report PORT
CONTROL on VHF on port channel
