Emails to and from ships at sea!

or, messages to and from ships at sea, for, when is all said and done, an e-mail is just a message.

What follows does not necessarily apply to warships but the theory, procedures, infrastructure and environment follows the same pattern!

Bearing in mind that ships have been exchanging messages with other ships at sea and with shore station for over 100 years now using Wireless Telegraphy, it should come as no surprise, that today in 2010, those exchanges are so sophisticated with the majority being automatically performed,  and the minority, performed by a person or persons with, well, let's just say, fewer skills that I needed between the years of 1953 and 1983. I kid you not that the operators at sea in merchant ships [radio officers long ago ceased to be] and members of the CIS branch of the navy, are trained as 'button pushers' and many of you out there with computer skills and a little training could so easily take over their jobs. To emphasize my point, at a recent tour of the Communication Training Section {Mercury Block} in HMS Collingwood [September 2010], the guide told his audience that the Section had some trainees who could neither read nor write on entry.

That this level of hands-off technical sophistication is inevitable in our highly technical world, means that not only are operators no longer required but neither are the skilled radio electricians of old, for their job is supplanted by an army of board-changers when defects occur, and they are not even sailors but civilian employees of civilian companies contracted to keep the system[s] functional. My, what a change...what a turn around ?

Whilst I am reasonably up-to-speed on what the royal navy is doing in radio communication terms, I cannot set that knowledge down on paper for obvious reasons, so from hereonin, I will stick with generalisations and bias my page towards the mercantile fleet and its operations.

 The ultimate radio equipment fit in the new liner Queen Elizabeth reads as follows:-

RADAR; VHF; VHFDSC; VHFP; UHFP; MFRTT; HFRTU; ASAR; SART; SATF; EPIRB;

and much of that fit is mandatory to address these protocols

SOLAS; GMDS; SAR; AIS, which are respectively
a.  Safety of life at sea
b. Global maritime distress system
c. Search and Rescue
d. Automatic Identification System - not required in warships. This is a system which transmits and receives [from other ships in close proximity] every conceivable detail about the ship and its movements so that the onboard computer linked to the ships sensors can work out the CPA [Closest Point of Approach] of other vessels and therefore avoid near collisions. It uses two VHF channels working in Duplex and these are channels 89 {AIS 1 = 161.975MHz} and 90 {AIS 2 = 162.025MHz} of the VHF IMM Band - see VHFDSC below. The faster the ship travels and the more manoeuvres it makes the quicker it repeats its identifying credentials: at 25 knots this is every two second, an almost continuous 'squirt' of information. Its range is said to be 30 nm. A sign of the times is that ship's masters are advised to turn off their AIS when sailing in waters known to be frequented by pirates etc.  The AIS is an off the shelf commercial product and all one needs is a receiver tuned to either of the AIS channels [see above] and an AIS computer terminal to pin-point the target with Radar fitted to encompass all these protocols manifest in safe navigation.

Returning to the radio equipment fit above, the next piece of kit after radar is

VHF. This is the IMM Band VHF having the long familiar Channel 16 as the distress frequency amongst many other simplex or duplex channels with channels 11, 12, and 13 {inter ship working} used a great deal near to naval ports. It is a set found even in the smallest of pleasure yachts.

Next VHFDSC is the same frequency VHF band as above [88 channels in the range 156.025 Mhz to 161.975Mhz} the DSC [Digital Selective Calling] channel for DISTRESS being channel 70 {156.525Mhz}.

VHFP offers a much larger frequency range of 146Mhz to 174Mhz which takes into account the VHF band we have just mentioned. The letter 'P' after 'VHF' stands for PUBLIC.  In this extended band there is provision for public communications using voice and narrowband [NB] to wideband [WB] data at these terrestrial frequencies.

UHFP, the 'P' again meaning PUBLIC, covers the frequency band of 300 Mhz to 500Mhz and 806Mhz to 869Mhz for public voice and narrowband to wideband data communications.  700Mhz is reserved for Public Safety broadband [BB] wide area coverage.

MFRTT Medium Frequency RTTY - Radio teleprinter. A teletypewriter used in a communication system using radio circuits. Mark/space teletypewriter signals are modulated on radio systems either by a two frequency shift of the carrier wave, called frequency shift keying (FSK) or by a two frequency audio signal, called voice frequency telegraph (VFT) or audio frequency shift keying (AFSK)

HFRTU is a High Frequency Receiver Transmitter Unit [in short, a HF transceiver] for use when communicating by HF in the band above approximately 3MHz to approximately 30MHz.  Formal abbreviation is FWS meaning fixed wireless system. Telecommunication systems operating in the fixed service including, for example, radio-relay systems, HF systems,  which support a range of applications. This is now Advanced Digital HF and not at all like the HF [short wave] of the pre-war to 1980 period.

ASAR Access Gateway [GS] A Gateway that connects one network to another network and performs some interworking function between the different networks. Used on Inmarsat {Satcoms} for radio traffic and emails. Part of this gateway supports GPS and world wide satellite TV channels/Reuter Press. For many years [25 in all] 'Inmarsat A' was an analogue system. In 2007 it changed to become a digital system and 'Inmarsat B' took over. There are other Inmarsat Channels in use, one known as a mini channel.  It is a highly sophisticated and mega fast high capacity system operating in the lower SHF frequency spectrum around the 1.5 to 1.6 GHz band. The naval satellite system operates in the upper band around the 7-8GHz bands using a satellite system called Skynet.  They also use a UHF Satellite system for submarines.  Queen Elizabeth is fitted with the FB500 system [FLEET BROADBAND] with the following technical parameters:-

  FB250 FB500
Data  
- Standard IP up to 284 kbps up to 432 kbps
- Streaming IP 32, 64, 128 kbps 32, 64, 128, 256 kbps
- ISDN 64 kbps
Voice 4 kbps and digital 3.1 kHz audio
Fax Group 3 fax via 3.1 kHz audio
SMS Standard 3G (up to 160 characters)
Remember as always, the difference between lower case and upper case letters and mathematical constants.

kbps {small 'b'}= kilo [thousands] of bits per second whereas 1kB {large 'B'} = kilo [thousand - actually 1024} of Bytes per second.  When changing to Mega, viz MB [million] always use an upper casing letter 'M' - thus 20MB = 20 Mega Bytes There are always 8 bits in a Byte whether calculating in kilo, in Mega or in Giga {and beyond} !

Using your own knowledge [and experience] of using the Internet, your ISP may tell you that your connection speed is up to 20Mb.  Since there are 8 bits in a Byte, that means up to a speed of 20 ÷ 8 = 2.5 MB [Mega Bytes]. Sadly, in reality in the UK and at medium to great distances away from main digital telephone exchanges using copper wire as feeds, that speed is often lower than 5Mb, meaning that your download speed is usually lower than 0.625 MB and when it gets to 1Mb [0.125 MB] it is the old fashion MODEM dial-up connection speed. Remember also that uploading speeds are always slower than downloading speeds.  If, as we are beginning to see, we are offered up to 50Mb [on fibre optics] that connection speed [in your dreams] could be up to 6.25MB. Given that a standard printed novel has about 1MB of information, this means that 6¼ novels could be downloaded in one second.  Impressive ? You bet.

Notice how much slower the speeds are over radio links, satellites included.

Based on 3G standards, Fleet Broadband provides constant, simultaneous access to voice and high-speed data services, on a global basis. Send and receive email with large file attachments, run complex data applications and make voice calls - all at the same time!

SART is a Search and Rescue Radar Transponder polarised in either horizontal or circular modulation in the 9200Mhz to 9500Mhz band

SAT F GMDSS - Global Maritime Distress and Safety System

    EPIRB's are Emergency Position Indicating Radio Beacon's. They cover the frequency range of
 

 EPIRB operating on 2 182 kHz;
 EPIRB operating on 121.5 MHz;
 EPIRB operating on 243 MHz;
 EPIRB operating on 156.525 MHz;
 Satellite EPIRB operating in the band 406-406.1 MHz;

and the Queen Elizabeth has 'B' 'C' and 'E' fitted.  When cruising,  she could keep watch on 2182kHz and IMM Channel 70 [156.525] when required. There are many EPIRB's onboard with every lifeboat and liferaft fitted.

She has DSC [Digital Selective Calling] on MF and HF too, operating on the HF Distress frequencies of 4207.5 kHz; 6312kHz; 8414.5kHz; 12577kHz and 16804.5kHz. Note that the age old distress frequency of 500 kHz [five ton] is no longer used as such.  It is now used by HAMS.

Her most important MSI computer [Maritime Safety Information] can have two inputs [two receivers] getting her information from either a satellite receiver [using Inmarsat EGC system] - a continuous connection supplemented by either a HF Narrow Band Direct Printing Telegraphy [Teleprinter] signal when on the high seas using the frequencies 12.579MHz; 16.806MHz; 19.680MHz; 22.376MHz and 26.100MHz or, when in coastal waters, on 518kHz. These facilities deliver NAVTEX which stands for Navigational TELEX.

Except for MSI above, she uses the less expensive HF to supplement her expensive SATCOMS, to send e-mails and other data ashore - she also receives by HF of course when necessary. Being a massive liner with over 2000 passengers the majority of whom will want to spend some part of each day in the liner's cyber cafe sending and receiving emails and generally 'surfing'  plus her own self generated radio traffic,  means that her connections have to be robust, reliable, speedy and accurate at all times. Her satellite connections are basically two fold. First she uses the UP LINK [from ship to space] of 1626.5MHz to 1660.5MHz  to send her emails and data to shore and receives the DOWN LINK [from space to ship] on 1525MHz to 1559MHz culminating in the ships server and MFRTT systems. Additionally, she can also use the satellite for Distress and Safety Operations [D&S OPS] with the UP LINK on 1645.5MHz to 1646.5MHz and the DOWN LINK on 1544MHz to 1549MHz.

Like all merchant ships at sea, the Queen Elizabeth will use a complete "e-mail system" and probably the well known system called WAVEMAIL. Wavemail also renders the HF Narrow Band Direct Printing Telegraph [Teleprinter] Service obsolete for this system is fully suitable for MSI information also.

The picture below gives you some idea of how it all works. In this case drawn for SATCOM working, but for Satcom read HF where relevant. SATCOMS is the easiest and most reliable transmission route, so whenever possible, it is used. For many ships and shore wireless stations,  HF is not even available for use [nor fitted].

ship SATCOM  email system.jpg

with the following associated text:

SMTP [Simple Mail Transfer Protocol] is the mail server that send mail for you.  In other words, when you click ‘send’ your email message is sent to the SMTP, where it s relayed to its destination.

POP3 [Post Office Protocol 3].  This is the server which stores your email for you. Email comes in through the SMTP server and is stored on a server called the POP3 server, until you download it with your email client.

In cases where more capacity is required, the vessel can buy more time from the SATLINK provider  or employ a different channel. In many cases, the SMTP and the POP3 servers  use the same physical computer.

See also this page WHAT_IS_IN_A_SHIPS_NAME_AND_ITS_RADIO_CALLSIGN