re: iridium

[ccscott49]

re: iridium

I know Andrew Bray is testing one of these on the ARC, but I tried to find out about costs etc, from, enquiries@next-destination.co.uk twice but, have had no reply from them, do we know of somebody else who would give me the rundown rather than the runaround! Please.

<P ID="edit"><FONT SIZE=-1>Edited by ccscott49 on Thu Nov 29 09:34:44 2001 (server time).</FONT></P>

 

[Boatman]

When you get a reply I will be interested I have been trying to get hold of one for quite a while, it appears only the US military get the right service, but I suppose if you do buy 10,000

 

[ccscott49]

Or you are the editor of yachting world!

 

[alant]

Does anyone have experience/knowledge of Inmarsat C, mini-C, mini-M as well as Iridium?
Is the coverage similar? (what happens eg. Southern Hemisphere)
What about download times for eg. "weather charts"?
Also relative costs of subscription & running these systems.

 

[ccscott49]

I would be interested in that aswell

 

[HaraldS]

I'm also quite interested to hear any practical feedback on these.
In theory Iridium coverage should be equal anywhere on the planet, well maybe a bit better towards the orbital nodes, because they run low orbit satellites. Inmarast is run from geostationary satlellites which cannot cover the polar areas. The mini-M uses spot beams to bring more power to favorite areas and this way allows smaller antennas, but less coverage.
Price wise the revived Iridium seems hard to beat, no fixed cost and about half the cost per minute than with Inmarsat if the call is initiated from the Iridium phone. The phones are also a lot cheaper. On the other hand, Inmarsat seems well proven and with good support. Specified data rates are low 2400 Baud on both, but I suspect in reality mini-M would turn out better on that account. If you are using a cell phone on the boat for data connection, you know how slow 9600 is, so 2400 is real bad news. Inmarsat-B gives you an ISDN speed connection with 64kBaud, but the antenna would sink most boats.
A couple isues back in Yachting World there was an article by Brian Savage who got an Iridium set and was experimenting with it doing e-mail, it was quite positive if I remeber right.

 

[ccscott49]

Just got the info, you can get 10kbs from this unit, so that isnt bad, same as my GSM on the confuser. The charges they will send to you. The contact I got was astlondon@aol.com, they answered in less than 15 minutes! Thats pretty good service already! £520 for the phone is only twice the price of a nokia 6210, without contract, I know I just bought one. So that is also not bad, the data connection thingy and software is £150, I paid £35 for the cable for the nokia, so again thats not bad, bottom line is I'm going for the iridium, not yet though in a few months. After I've got a little more feedback and seen Andrew Brays' report on this system on the ARC. Thanks for all the input

 

[HaraldS]

Have you checked out www.iridium.com?
They list a large number of distributors and have details for their system.
The 10kbit is through compression, straight to the internet, they list dial-up point-to-point as 2.4kbit. I wouldn't expect cell phone performance from that.

 

[ccscott49]

I checked out that site, they put me onto the uk site, then the uk site put me onto AST, where I got the prices etc. Isnt the data rate direct to internet for e mail what we need?

 

[billskip]

if ya gonna flog ya nokia let me know pls...ta

 

[HaraldS]

Yes the internet access is proably the way to go, BUT:
The dial-up data rate gives the true rate up to the destination modem.
If you dial up to your own provider, say AOL or AT&T, you will establish a PPP connection, which by it's standard uses compression, so that the effective data rate would be better. How much depends a lot on what goes over the wire.
Iridium may not use the PPP standard compression when you go to their Internet gateway, and they may well have something better, but not likley a lot better.
Via it's PPP connection the regular cell phone also gets compression and more than the 9600bits/s. This kind of compression is poor on already compressed data like MP3, or JPEG. So if you think about sending pictures from the middle of the ocean it will probably not help much and a low quality picture of 50k bytes would take three minutes. It will probably be fine for just text e-mail. I think there are also some e-mail providers that specilaize on low bandwidth clients that might be worth checking out in such case.

I have been deferring my decision as I have mostly been within cell phone reach during the last years, but that will change abit this comming summer, so I might have to make up my mind.

By the way I found out when sailing by, that the Norwegian oil riggs provide GSM coverage some 30 miles around them.

 

[ccscott49]

Funnily enough I'm on a norwegian oil rig, the ekofisk cmplex, largest complex around, and we dont have GSM coverage here, not that it would be much use, as by norwegian law we are not allowed to bring mobile phones off shore, they are taken off us at the heliport, due to us using equipment out here that may be affected and explode! if radio trasmisions of any type are used, we do have periods of radio silence, when things like peforating guns are on surface. So basically why would we have GSM phone coverage, sounds very strange, I will investigate!

 

[HaraldS]

Interesting. Forgot the name of the rig, but can probably find it out again. It was the first thing we hit on a pretty straight line from Stavanger to Inverness. I lost the Norwegian land signal about 50 miles offshore with the mast head antenna, and then next morning as we approached the rig we got signal again, getting stronger as we got closer and we had it for several hours. It was the main Norwegian provider.

 

[ccscott49]

leaving stavanger for inverness, you would just about pass us, was it a platform or a mobile rig?

 

[HaraldS]

I'm quite sure it wasn't Echofisk. Somethingwith starting with "S"??
Have pictures of it, but don't know if it's possible to post them on this board.

 

[ccscott49]

You can send them to me direct, on ccscott49@hotmail.com it was probably a drilling rig, not a platform, some of them use GSM for shore to rig comunications and it could well have been a rogue signal, did you try using it? Most of the platforms out here use a microwave system, with the phone/data signals supeimposed on top of the microwave carrier, you never know what could have been going on, but as a rule, we do not allow phones offshore Norway, some places in UK yes, but even there not many, and I've never had a mobile work off shore when they let us carry them, except in Holland and then we could wave to the nude sunbathers on the beach!

 

[HaraldS]

Did send you the picture. Now remember platform was called Sleipner, it was two interconnected. No nude sun-bathers on them though.

 

[Mirelle]

We're trying it out on some of our tankers. Cost comes out at about 80 cents per minute US mobile to mobile; mobile to landline is a bit over a dollar a minute, a handset will be about US$ 1,500.00

Those of my colleagues who know about these things don't rate it at all for data; we use Inmarsat for that. A Mini-M terminal will set you back about US$5,000.00, and you need to buy a data compression system also, but for serious stuff you should be using an A or B set (move decimal point one step the wromg way!) or, (coming shortly, allegedly 1Q 2002), Inmarsat Fleet (ex Inmarsat F) which offers a packet data service.

The next generation of GEO satellites which will be packet switched are still being built.

 

[Guest]

An inconsequential piece of information which, however, some of you might find interesting.

Iridium satellites can be easily seen by the naked eye, sometimes even in daylight, if you know where and when to look. As they fly over, the solar panels reflect the sunlight and act rather like signalling mirrors. This only lasts for a second or two but is very bright and the events have been labelled 'Iridium flares'.

The awesome mathematicians can predict precisely when and from where they can be seen. Details are at Heavens-Above.com

 

[ccscott49]

Cost of handset in UK now £520, which atarts to make sense, but data rate is slow, I may do what you say and wait a while and see what the prices do over the next year or so. I wont need one until then. Thanks for your input!