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Iridium service is 100% global, even on the north and south poles. It uses a large constellation of low earth orbit satellites.

Inmarsat has no coverage north of 75 degrees N and south of 50 degrees S latitude.

Inmarsat also has a satellite over the pacific which (according to the picture) covers the southern arc. Why couldn't they triangulate from both satellites?

Further, the Jindalee Operational Radar Network in Australia is an over the horizon radar capable of sensing a four seater airplane like a cessna from 2600km away. Why didn't they see a plane 6-8 times larger and several hundred kilometers closer?

Unfortunately, this map has non-factual locations for the circles other than 8:11. The angle information for the earlier pings has not been released, but artwork was drawn up that estimated these earlier pings from the reported estimated tracks attributed to the NTSB. This artwork, drawn by Scott Henderson, was likely the source for the map on theaviationist.com's site. See http://willyloman.wordpress.co... for details.

Inmarsat has been coy about the exact value of the ping angles. They issued a press release that said that the information had been given to the Malaysian government, and that anyone who wanted details should contact Malaysia. See http://www.inmarsat.com/news/i... IMHO, they have been doing this because the earlier ping data may make clearer that the aircraft track takes it over Malaysia, where the lack of detection may be a source of official embarrassment.

The earlier ping data may also indicate whether MH370 overflew Indonesia, or whether it flew west to avoid Indonesia, and that has an effect on the plane's remaining range and the estimate of the flight's bearing when it presumably turned southward toward the 90E/45S region where the SAR operations have been focused lately. It would appear that this data was factored into the NTSB track estimates, but the lack of an official release of the angle data has hampered the armchair/amateur speculation about the location. IMHO, if MH370 avoided overflying Indonesia, it may have been a deliberate attempt to lay a false track in a west or northwest direction.

More speculation: the coverage maps that I've found for the satellite company that was doing the pings don't have an obvious blind spot where the arcs end: http://www.inmarsat.com/?s=cov... so perhaps they are working from knowing which transmitting antenna sent the ping request if they happen to use more than one antenna to get full coverage. Ping on one antenna, get a response, then done, no response, try the other antenna....

Actually, it's more like 1.5s. (based on a BGAN system in my driveway. 1.2s from the walmart parking lot -- wide open sky) It's the most expensive internet I know of, but it works f'ing everywhere. (Antarctica not included.)

You are a bit behind the times, there is a service for ships on the high seas that offers borderline broadband data rates.

http://www.inmarsat.com/Services/Maritime/FleetBroadband/default.aspx

At $18.00 / MByte you'd have to be pretty rich to use it for anything but essential communications though.

I have found AIS to the be the tech I'd least like to be without in costal waters, certainly in Northern Europe. The shipping lanes are a serious headache around the English Channel and the North Sea. Being able to see (hopefully) all ships that might be of concern and being able to get their MMSI and give them a call is incredibly handy.

I suppose I'm assuming you have all the standard kit on board (VHF DSC, decent GPS / plotter, (G)EPIRB).

If you're planning round the world, you'll be wanting more interesting radio tech...

Oh, and good batteries and power management is a god send. Without it your power budgets have to have such absurd safety margins you almost always end up needing jerrycans full of diesel everywhere.

Obviously, this being Slashdot, I would have to suggest something like this http://www.inmarsat.com/Services/Maritime/FleetBroadband/SAILOR_250_FleetBroadband.asp

http://www.inmarsat.com/

Now stop trying to make up excuses and deliberate impediments. It's not witty, it's asinine. Just because *you* may not have GSM coverage doesn't mean that nobody else does, or that it's not a viable option for a lot of people.

The phone system has one enormous advantage - person to person contact (as opposed to point to point). If you're out on a ship in the middle of the ocean, you can use an HF radio to contact someone almost anywhere in the world. Sometimes. However, both parties have to have similar equipment which requires a modicum of training to use. The 'old' way was marine mobile radio - you contact a marine operator via HF radio and they patched you into the phone system. That was still expensive, didn't always work and not very private.

The Inmarsat (Warning - Stupid Flash site) system works pretty well and has taken over marine mobile communications. It's still rather expensive but people running boats are used to that. Remember the usual working analogy to sailing - standing in a cold shower ripping up hundred dollar bills. If you're financial case is built on people like that, you're halfway there without lifting a finger.

The choices on an ocean aren't so different to what you get on land. There are fewer options generally and since scarcity drives price you can expect prices to go up.

Your options in rough speed order are:

- SSB
- Satellite Phone such as Iridium / Inmarsat Fleetbroadband
- VSat system

( overview of the sat phones: Satellite Phone Equipment Overview )

Then of course when you are near shore (10s meters to 10s miles) you have the usual culprits:
- Wifi
- GSM cell phones

All have their pros and conns:
- SSB is dismally slow and requires a bunch of experience to learn to use. Hard on ships batteries also. However, very long distance cruisers with plenty of time and patience seem to enjoy it. Sailmail is the market leader, but also you have Airmail for hams and smaller providers

- Iridium is nearly as slow as SSB, but a lot more "instant" and much more like a slow speed dialup internet connection. Reasonably pricey (Iridium Prepay Prices) It's *required* that you use some kind of email acceleration such as ExpressMail or GMN/Ocens or whatever

- BGAN/Fleetbroadband is near low end broadband speeds, but costs something similar to roaming cell phone prices and so its very cost effective for basic browsing, but not really priced for cruising slashdot daily. However, its about the best you can get for a price in single digits of thousands of dollars

- VSAT is your big geo stationary satellites that are rented out for sat TV, etc. Providers lease some space and give you a (very) big dish. The dishes need to be pointed extremely accurately, are quite large (60cm to 2m) and for marine use you are talking tens of thousands of dollars for equipment. However, fixed price, large volume contracts can be had for single digit thousands of dollars per month... So if you really are a business and need always on bandwidth then this is your option (think cruiseliner, some merchant vessels, super-yachts). The issue is that the market is fragmented and you need a provider who has rented space on multiple satellites to get anything like reasonable coverage - usually a Fleetbroadband is still needed to complete your coverage...

This was asked sooner than 10 years ago, and I'll repeat my answer to that thread.

You want BGAN. It's an INMARSAT service. Designed for marine use, but will not be cheap

http://www.inmarsat.com/Services/Land/BGAN/default.aspx

Have you used a Iridium phone? With their call dropping I wouldn't want to trust on them in a Emergency (with the exception of if I was going to the North or South Pole where Inmarsat is not available). No, get a IsatPhone if you want something reliable http://www.inmarsat.com/Services/Land/IsatPhone/default.aspx which you just have a "see the sky, point antenna at sky, make call" operation.

That's the way I'd do it. Get service from a company like http://www.inmarsat.com/ and a decent sized sailboat full of food, water, fuel, and books, and I'll be happy floating around the Pacific for a month.

Inmarsat BGAN
http://www.inmarsat.com/Services/Land/BGAN/default.aspx

http://www.inmarsat.com/Services/Land/BGAN/default.aspx

. . . about the most info I can find so far comes from their press release

BGAN is an IP and circuit-switched service that will offer voice telephony and a sophisticated range of high-bandwidth services, including internet access, videoconferencing, LAN and other data services, at speeds up to half a megabit per second.

Of course this means jack-shit in real world practicalities, and don't forget it doesn't mention those wonderful ping times.

So all in all, a fairly useless piece of info, but hey, at least we know that these satellites are

60 times more powerful and have 20 times more capacity than their predecessors, the Inmarsat-3 satellites.

I can rest easy now.

Yes, the article is lacking. But, you can get the answer by googling for "BGan Inmarsat" (I got the terms from TFA). Or you can go directly to Inmarsat's webpage: http://countdown.inmarsat.com/bgan/default.aspx?to p_level_id=31&language=EN&textonly=False.

It's up to 492Kbps, send and receive, for variable bit rate. For guaranteed bit rate, it's up to 256Kbps. I don't know if that means X Kbps each direction, or combined. Maybe someone else can fill in the gaps.

so if youre smack dab in the middle of central Africa, theres NO way to communicate back except maybe long range ham radio.

Ahem. Inmarsat has been around for decades and covers all of Africa. There are local agents who can hook you up with rental Inmarsat briefcase-sized communications units. Inmarsat has also had fax, store-and-forward, as well as packet data for a long time and have in recent years been providing high-speed data, too.

The reason you only got "a couple listings" is because Iridium is pretty much the only game in town, and there's pretty much only one pager. There weren't exactly a lot of devices made for this market. It's no small feat to operate a global voice/data satellite network. There are only a "couple" of other providers (geared more toward government, military, and enterprise, and without "pager" offerings): InMarSat and GlobalStar, for example.

The Motorola 9501 for Iridium is, as I said, essentially the only satellite pager:

http://www.iridium.com/product/iri_product-detail. asp?productid=445

http://shop.infosat.com/pagers/

http://www.infosat.com/services/iridium/motorola_9 501_pager.htm

http://www.satwest.com/satellite_pagers_mi9501.htm l

More...

Of course, you may be interested in a satellite handset, not strictly a "pager", than can also get email and numeric messages. Keep in mind, though, that all of these satellite devices are subject to normal satellite requirements, e.g., line of sight to the sky. Yes, sometimes they'll "kind of" work in vehicles, wooded areas, etc., and you will get confirmed delivery of messages once you're again in range, but these things aren't exactly set up to work in houses and buildings. You may have no choice but to have a conventional cell phone/pager AND a satellite device for when you're remote, and have your automated systems and/or people try both devices.

For others in a similar boat, but not quite as remote as the submitter, you may also consider a conventional 2-way or 1.5-way nationwide pager, which provides delivery confirmation and re-attempts if you're temporarily out of range. But if you know you're going to be out of range for a while, you pretty much restricted to something like one of the satellite solutions. Consider a mobile phone. Most providers' digital networks offer email service, numeric "paging", and even true TAP/IXO paging. Just look into a provider that covers your area(s).

A bit of history on Iridium: Iridium was the satellite phone service launched by Motorola on Sept 23, 1998, when the last satellite of its global constellation was in place. Handset prices (over $3000) and airtime fees (several dollars per minute), as well as attempting to market to ordinary folks doomed the service from the beginning. Motorola decided to end the Iridium service on March 17, 2000, at 11:59pm. After billions were spent on the 66 satellites, and the $1 million per month that it cost Motorola for Boeing operate the satellites, Motorola initiated plans to deorbit and destroy the constellation. Various investor groups attempted to save Iridium, and the Defense Department even provided $72 million to keep the satellites operational (in the face of concerns of debris from the deorbited satellites actually hitting someone on earth, which NASA pinned at 1 in 250). In any event, Iridium Satellite LLC successfully purchased the assets of the $7 billion Motorola Iridium program in November 2000 for a mere $25 million:

http://spaceflightnow.com/news/n0011/16iridium/
http://spaceflightnow.com/news/n0103/29iridium/

The new Iridium, launched in March 2001, attempts to fix the shortcomings of the original by expanding beyond satellite voice telephone service, into data, video, realtime monitoring, and special applications in markets such as mining, oil/gas, m

My job right now is sysadmin of a web based GPS tracking system. There are terminals available that will track using GPS, sending the information back via a service provider, either satellite or some sort of mobile device (GPRS or SMS). However I can't see how Coke would fit this sort of thing inside a Coke can! The terminals we use are ~2x5x10cm. Also as someone else has pointed out, for satellite comms to work you need to be outside, although GPRS would work indoors. This all applies to Australia, not sure what sort of mobile technology you could use in the US.

Satellite comms examples: Inmarsat C/D+, Startrack (flash site).

The news organizations use InMarSat video terminals -- it's a 64k ISDN connection, which is why it is so grainy.

We do a lot of this (for medical projects) and sometimes mux two channels for a 128k connection, but it is not something you'd want to troubleshoot in the field with a non-technical person. It also gets a lot bigger in size, while the little video systems the news guys have all fit in a small briefcase and have a single panel dish built in.

Actually, it's a phone that's made in england.

The 'videophone' of CNN/FNC/et al lore is a 7E Communications Talking Head. It's a $8.00/minute Inmarsat hooker-upper.

Inmarsat terminals can be quite small: modern terminals are basically the size of a laptop PC, with a fold-out three panel antenna which you mount on the lid (e.g. Nera World Communicator). You generally tell the terminal your position on the globe, and it tells you which direction to point the antenna to see the satellite. It doesn't need to be pin point accurate, and you'll have a signal strength meter so you just wiggle the thing about until you get the best signal. I think the videophone has a 40cm folding antenna that you connect externally.

For data, your computer sees the satellite terminal as though it were an ISDN line, and you get up to 64kbps - hence the restrictions to the audio/video quality. The key thing about 7E's videophone is that all the kit you need is integrated into a single case, and it's been made simple enough for news field crews to use.