City of London Training Site
sister site - freewebs.com/mvslondon ....................
COMMUNICATIONS
Click on "SIGNALS" for a cyber fast track to the sister-page
" From 19 November 2007, for a period of about nine months the river wall immediately downstream of Canary Wharf Pier will be rebuilt. The majority of the work will be conducted from the shore, however at times works will be conducted from brackets hung on the river side of the sheet pile wall. Listen on 14 for daily condition. " Right! What is a " 14 " ? Come to think of it; what is a Notice to Mariners
http://www.freewebs.com/kjtraining/shipsradio.htmWhat is that Lighthouse in the Top-Right-Corner about? Is it? flashing, occulting or isophase ? NOT WORKING ?
radio terminology
speed of light,
wavelength,
frequency,
modulation, Google ALL those terms and get some idea what they are about.
Click on this link GMDSS
Radiation is transfer of energy without any supporting cables or ties.
The sun radiates energy constantly to earth across 93, 000, 000 miles of 'space'.
visible light, so we can see what we're doing by day and have colour in our lives
infra-red heat, to keep us warm and to maintain a constant temperature in the planet.
ultra-violet energy which may burn the skin, or produce vitamin D in it.
magnetic waves, give us the northern lights, storms & wind & unwind natural clocks.
Radio waves, which are not much practical use as they are very jumbled up.
x-rays, alpha, beta, delta and gamma rays, all of which can be quite unpleasant.
The sun does not send darkness, by the way. Darkness is absense of light.
MARINE CHANNELS
LISTEN ON 16 UNLESS TOLD OTHERWISE.
ALWAYS BROADCAST ON LO POWER. except in ONE notable exception
http://www.tcdlife.ie/clubs/subaqua/Equipment/VHF_radios.php
VHF From the Sub-Aqua club of Trinity College Dublin!
all about ham radio but all radio is the same!
Anytime you want to call anyone you can use 16 (156.800).
Everybody at sea is supposed to guard 16 at all times. (156.800MHz)
It allows one to negotiate a quiet [simplex] channel
Otherwise, use appropriate promulgated channels
for appropopriate comms. Is that a Roger?
Never ever broadcast on 70! Why not?
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70 (156.525Mhz) used ONLY for DSC. q.v.Yes! Click on it!
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13 156.650 Intership Port(simplex): Poplar Marina H24 (also an int. watch channel)
14 156.700 Port(simplex): Woolwich Radio +15 & +45 nav info. tide state etc
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75 156.7625 156.7875 lower guard for 16
16 Calling and Safety: 156.800 Channels 75 & 76 'guard' 16.
76 156.8125 156.8375 upper guard for 16
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80 157.025 Port(duplex): 161.625 (Gallions Pt. Marina)
22 157.100 Port(duplex): 161.700 (Woolwich radio-telephone)
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(Marinas generally use 157.025MHz (channel 80 subject to checking! )
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Ship to Shore, comms. control rests with the Shore station (with on important exception)
Ship to Ship the calling station holds comms. control.
Marine Channels
Pri/Sec boat (duplex channels) shore
0 156.000Mhz is dedicated to Search & Rescue (SAR)
60 156.025 Port(duplex): 160.625 Public correspondence:
1 156.050 Port(duplex): 160.650 Public correspondence:
61 156.075 Port(duplex): 160.675 Public correspondence:
2 156.100 Port (duplex): 160.700 Public correspondence:
62 156.125 Port (duplex): 160.725 Public correspondence:
3 156.150 Port (duplex): 160.750 Public correspondence:
63 156.175 Port (duplex): 160.775 Public correspondence:
4 156.200 Port(duplex): 160.800 Public correspondence:
64 156.225 Port(duplex): 160.825 Public correspondence:
5 156.250 Port(duplex): 160.850 Public correspondence:
65 156.275 Port(duplex): 160.875 Public correspondence:
6 156.300 Intership (simplex) Uk preferred ship to ship
66 156.325 Port(duplex): 160.925 Public correspondence:
7 (duplex): 160.950 Public correspondence:
67 156.375 Intership Port(simplex): (SAR helicopters).
8 156.400 Intership(simplex) UK-preferred ship-to-ship (Thames Tugs)
68 156.425 H and H+30 Port(simplex): Port Control London SeaReach 4 & Crayford Ness
9 156.450 Intership Port(simplex): (Whitstable harbour radio)
69 156.475 Port(simplex):
10 156.500 (Thames Tugs)Intership(simplex) (Kingsferry Bridge) coastguard weather and warnings
70 (156.525Mhz) used ONLY for DFS. q.v.
11 156.550 Port(simplex):
71 156.575 Port(simplex):
12 156.600 Port(simplex): Port Control London E. of SeaReach 4 & see 68
72 156.625 UK preferred ship to ship. (Thames Tugs)
13 156.650 Intership Port(simplex): Poplar Marina H24 (Thames Tugs)
73 156.675 Port(simplex): Coastguard wx & warnings
14 156.700 Port(simplex): (Burgan Fuel Barge) Woolwich Radio +15 & +45
74 156.725 Port(simplex): (Medway Radio)
15 156.750 Intership Port(simplex): (Thames Tugs)
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75 156.7625 156.7875 lower guard for 16
16 Calling and safety: 156.800 Channel 75 & 76 guard Ch16.
76 156.8125 156.8375 upper guard for 16
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17 156.850 Intership Port(simplex): (Thames Tugs)
77 156.875 Intership UK preferred ship to ship routine (Thames Tugs)
18 156.900 Port(duplex): 161.500
78 156.925 Port(duplex): 161.525
19 156.950 Port(duplex): 161.550
79 156.975 Port(duplex): 161.575
20 157.000 Port(duplex): 161.600
80 157.025 Port(duplex): 161.625 (Gallions Pt. Marina)
21 157.050 156.050-or-161.650 Port(duplex):
81 157.075 Port(duplex): 161.675
22 157.100 Port(duplex): 161.700 Woolwich radio-telephone
82 157.125 Port(duplex): 161.725 Public correspondence:
23 157.150 156.150 -or- 161.750 Public correspondence: coastguard wx & warnings
83 157.175 156.175 -or- 161.775 Public correspondence:
24 157.200 161.800 Public correspondence:
84 157.225 Port(duplex): 161.825 : coastguard wx & warnings.
25 157.250 161.850 Public correspondence:
85 157.275 161.875 Public correspondence:
26 157.300 161.900 Public correspondence:
86 157.325 161.925 : coastguard wx & warnings
27 157.350 161.950 Public correspondence:
87 157.375 161.975 Public correspondence:
28 157.400 162.000 Public correspondence:
88 157.425 162.025 Public correspondence:
Don't ask where channels 29 to 59 inclusive are. I have not found them yet. But you could work out the frequencies allocated to them and programme a scanner to find them
The pattern of frequencies
MORE RADIO
Radio is part of the Electromagnetic spectrum of energy which include microwaves, gamma rays, x-rays, light-waves, radio waves and others you don’t want or need to know about.
VHF is a defined band of the radio spectrum within frequencies of 30Mhz and 300Mhz or wavelengths of 10-1 metres. Marine Channels fall exactly in the middle of the VHF band as defined, using frequency ranges between 156MHz and 163MHz for all their purposes. Marine channels are sometimes (erroneously) referred to as the “2metre band”. This (truthfully) indicates that marine frequencies have a wavelength of 2 metres.
To understand the relationship between Wavelength and Frequency, you need to know something about the Speed of Light. All electromagnetic energy travels at much the same speed in a vacuum. Like 300 million metres in one second. This is the speed of light! An approximation perhaps but perfectly acceptable as a working yardstick in understanding how radio works. We need to know that light (and/or radio) has a finite speed.
To give you a [very] rough idea of the speed of light, it takes about 8 minutes for it to travel from the sun, which is 93,000,000 miles away from earth. It takes less than 2 seconds to get in from the moon which is about 250,000 miles away. And in theory, at least, it could circle the earth at the equator about seven times in one second.
Can't resist this bit of useful information. A "second" is a standard unit of measurement of the passage of time. The SI unit is defined as? Wait for it! The duration of 9192631770 periods of the radiation corresponding to the transition between thdese two hyperfine levels of the ground state of the Caesium 133 atom.
The only important number is 300 million metres (mentioned above as being the speed of light). When a radio signal transmits from an antenna it leaves at the Speed of Light. In one second, (if the signal were strong enough), it could reach a receiver 300,000kms away. In real life, a transmission on a marine channel will hit a receiving aerial instantly or as near's dammit.
Now look at ‘wavelength’. Electromagnetic energy is transmitted in waves. The energy stream is not constant and linear like, say, the flow of water from a hosepipe. It proceeds in pulses somewhat like the vibration of an insect’s wings but a bit quicker. The bumblebee on full song may manage 50 beats a second. Radio can make about 150 million cycles per second at marine frequencies.
So we have an energy source emmitting at 150Megahertz (that is how we say 150 million wingbeats per second: 150 Mhz) at a speed of 300 million metres per second. If we could see the energy passing we would see single waves 2metres long streaming past at a rate of 150Mhz. Let's talk about dingbats for a mo. If a dingbat can scoot at 300metres per second and an infinite number of dingbats were escaping from dingbat-hell one at a time but scooting off one after the other exactly 2metres apart, a casual observer might note that on the first and any subsequent 300m stretch there would always be 150 dingbats.
If you can make sense of dingbats, you can make sense of radio frequency, wavelength and the Speed of Light.
COMMUNICATIONS
Flag Kilo has a special significance communications.
Flown on its own it means
"I WOULD TALK WITH THEE". Or "TALK WITH ME"
"Talk To Me" is the motto of MVS CoL Comms.Cadre. Kilo is it's flag.
There are many forms of communication, some arcane, some archaic, some old, some new. ALL have their uses and all have their time. The oldest and most reliable form of communication is face-to-face conversation. Whether the F2F be talking animatedly or eating the face off some stuupo, it is communication.
If you want to communicate with someone a little further away, you might use a loud-hailer an aldis lamp or Verey flares (look it up! dictionaries are also a form of communication). You could communicate at a distance by waving, or using smoke signals. Mirrors have been used by day and bonfires at night.
The Architects of Stonehenge speak to modern man over eons. Pity we have not got the code. Marconi communicated across the Atlantic ocean by sending electric pulses through a copper wire.
At a further remove, signal flags have been used for over 200 years.
These are the agreed flags in use in this century in England and many other places.
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http://www.mcga.gov.uk/c4mca
QUOTING MCA directly from the link above.
By ‘communications’ in this context, we mean all aspects of the subject, from specific equipment issues – a radio or a mobile phone that does not work in a particular area, for example – through the human element – individuals failing to pass information on or insufficiently trained to understand correctly the information passed to them – to the overall picture – such as incomplete communications between responding organisations, sometimes stemming from a failure to understand each others’ roles, responsibilities and information needs.
It is well recognised that good communications are a key element in providing an efficient and effective response to any emergency. Yet ‘communications’ are often cited as having been a problem, to a greater or lesser extent, after major incidents or exercises. It is one of the areas of emergency response that needs most to be improved; it can be improved, often quite readily; and yet, perversely, it seems to be an area resistant to improvement! All those involved in emergency response should work to overcome that resistance before an emergency occurs as well as during it.
As an emergency response co-ordinating authority, the Maritime and Coastguard Agency is very keen to play its part and to ensure that all communications problems, of whatever type, are overcome. Publishing the information contained in this part of our site is just one of the ways in which we seek to achieve this aim.
Theory of radio
Radio is a form of electro-magnetic energy, characterised by being measured in wavelength and/or frequency and travelling outwards from its point of production at the speed of light. 'Speed of Light' is an operative term. Light itself is part of the Radio-Magnetic-Spectrum. You are already familiar with the concept of frequency and wavelength if you know how to change stations on your wireless.
As watermen delivering seamanship, we use radio to communicate. Obviously that nice kit with all the winky lights and the microphone the skipper talks into and the speakers that drown out your conversation are to do with radio. They allow boat-people to communicate with shore-people and even with each other when they can't find signal flags or aldis lamps or flares.
You need to know that your mobile is also a duplex radio. You better believe it as someday it might help save a life.
The list of 'frequencies' shown above for on-board radios is an internationally recognised slice of the Radio-Magnetic-Spectrum specifically designated for the use of those who go down to the sea in ships and them that watches out for them from the land [or overhead for that matter! Coastguard has fixed wing aircraft and choppers up there] . The marine band is known as the "Five Metre Band" because the wavelength of all or any7 of the 80 mchannels is about five metres.
The Theory of Radio.
When you press the transmit button, you energise a load of circuits which cause electromagnetic radiation to be emitted (in all directions) from the tip of the appropriate aerial somewhere above your head. This is called 'transmitting a carrier'.
The radiation will be sensed by any marine receiver up to 2-20 miles away so long as it is tuned to receive signals of the same wavelength or at the same frequency as the transmitted carrier emitting from your boat. A listener will sense that a 'silent signal' is coming out of the speakers of their receiver and will probably wonder why some nit is 'transmitting a carrier'.
They will wonder thus because, being skilled in the use and abuse of radio, they will know that for as long as that carrier stays on air, it has total control of that channel. The marine channels in general use are "Simplex". "Simplex" means the receiver receives the frequency transmitted, and transmits on the frequency received. The glutton on the button has to let go to free up the frequency, so that his transmitter can become a receiver.