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Old 29-09-2010, 10:28   #1
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Internet / Email Access via Iridium

I just installed an Iridium 9555 with a docking station and external antenna in preparation for our departure to the South Pacific. Part of my motivation for this was my wife (she wants to be able to talk to our children from time to time), as a back-up to HF radio to send/receive email and, in the event of a catastrophe, an alternate method of communications.

When I make the connection through my computer using the Iridium, it says that my connection rate is 9.6KBPS but regardless of whether I use Internet Explorer or Mozilla, both browsers time out before I can get to an email service like Gmail. I've even tried connecting to winlink.org but that too times out before I can connect.

The vendor from whom I purchased the phone says that's the nature of the beast and suggests I subscribe to ocens.com service at a rate of $240 per year. As a back up service, I'm not inclined to spend that much.

Does anyone else have solutions that work?

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Old 29-09-2010, 10:44   #2
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Pretty much ran into the same issues earlier this year. After much research came to the conclusion that the phone is a pretty lousy and slow way to get on the internet.
Google it. There is a lot of discussion out there on the subject.
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Old 29-09-2010, 11:13   #3
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Subscribe to OCENS. Works great and may cost less, or at least no much more than not using compression.

Forget trying to surf the web.
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Old 29-09-2010, 11:36   #4
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Look at XGate and XWeb from Global Marine Networks: Satellite EMail for Iridium - Inmarsat - Thuraya - BGAN - Fleet Broadband | Global Marine Networks

I have been a satisfied XGate customer for many years. I have not tried XWeb. You absolutely need to use a satellite-optimized service like XGate or OCENS. If you search Cruiser's Forum you will find many discussions on this topic.
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Old 29-09-2010, 12:26   #5
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I suspect that the 9600 bps connection is between your laptop and the phone. On Iridium you won't get more than 2400 bps between the phone and the world. You simply won't be able to reliably connect over the web using Iridium. Between latency and slow speeds it isn't going to happen.

The compression services like Ocens and XGate help a lot, but it's still deathly slow.
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Old 29-09-2010, 19:50   #6
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Iridium is not suited to anything that's needs a browser to access it. It's effectively 2400 baud and most HTML servers will time out at this throughput. For email use a direct email client ( I used outlook express) and subscribe to a dedicated email service

Dave
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Old 01-10-2010, 09:23   #7
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Iridium + Compression

Hello All,

The iridium connection to the internet runs at a nominal 2400 baud. Actually, its less than that. On average when streaming you can send about 15Kbytes of data in one minute. So... the connection is slow. However, this is not the only factor slowing things down. The latency on the network is large. This causes big delays when requesting data from the internet since it takes on average 1.5 seconds for a request to make it to the server and then back. i.e. pings take 1.5-3 seconds.

So... when browsing not only are you using a link which is 20 times slower than a dialup but you have a 1.5 second delay for every link you hit. As you have discovered browsing without some sort of optimization software does not work.

The same is true for e-mail. Using outlook express with an ISP does not work well because of the slow speed, large time delays, and also no midfile restart. Take sending an e-mail with outlook express to 5 recipients. The smtp protocol, which is what outlook express uses for sending mail, requires 5 line turn arounds for setup and one line turn around for every recipient. This means that before you have sent a single byte of data you have consumed 10 * 3 sec or 30 seconds of air time. That is $0.75 for one e-mail and you still have not sent a single byte of the message. And... if you were to have a satellite link drop in the middle of your transmission (an often event with iridium) then you get to start all over!

So... to do any kind of e-mail you need software which optimizes the link.

For web browsing GMN offers xweb which on average compresses your web pages down by a factor of 3-5x. This means that instead of browsing the internet at 2.4kbps you browse at 9-15kbps which is still considerably slower than a dialup and you still have the latencies. So... XWeb helps by taking a reall-really slow connection and making it just really slow. You can disable images in your browser which helps a lot but eliminates a lot of the content.

XGate e-mail is another story. There are many thousands of users on everything from small sailboats to cruise ships using this software over Iridium every day. On average XGate will send 10 2-10kb mixed text/html mesgs in less than 1 minute. Please visit the web for additional information.

I hope this helps.

Take care.

--luis

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Old 01-10-2010, 16:04   #8
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useful to know that

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Old 01-10-2010, 16:20   #9
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Just for entertainment value, it's interesting to note that access to Winlink or Sailmail over HF/SSB using Pactor III is faster than Iridium.

Pactor II 1200 bps
Iridium 2400 bps
Pactor III 5200 bps
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Old 01-10-2010, 16:37   #10
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well pactor III sometime does

"After protocol overhead, PACTOR-III achieves an effective throughput of up to 2722 Bit/s without compression. If plain text is transmitted, the built-in Pseudo Markov compression allows an effective throughput of up to 5200 Bit/s"


Iridiums " effective throughput" with compression is 9600 bps

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Old 01-10-2010, 17:35   #11
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If you're going to compare apples to apples you have to allow for the overhead on the Iridium connection also.

I've used Iridium a good bit and never seen anything like 9600 bps even with compression. Are you confusing it with Globalstar on the occasions one can actually get a connect? *grin* Have you measured throughput or are you quoting something?
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Old 01-10-2010, 17:37   #12
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Quote:
Originally Posted by goboatingnow View Post
well pactor III sometime does

"After protocol overhead, PACTOR-III achieves an effective throughput of up to 2722 Bit/s without compression. If plain text is transmitted, the built-in Pseudo Markov compression allows an effective throughput of up to 5200 Bit/s"


Iridiums " effective throughput" with compression is 9600 bps

dave
You guys are looking at theoretical values. In the field the effective throughput is much less for pactor than iridium. Iridium effectively transfers about 15Kbytes of raw data per minute. A really good pactor III connection will do 10Kbytes per minute. However, you usually see in the 1-5Kbytes per minute range out of pactor III. The other thing to keep in mind is that line turns arounds with pactor III are deathly slow. With iridium you have 1-3 seconds. For pactor III its 10 seconds or more.

The big win with Iridium is consistency. no matter where you are on the planet you can expect to connect quickly and have consistent data rates. With pactor its a toss up whether you will event get connected. with HF you have station contention, user contention, ionosphere propagation issues, grounding and RF issues, and....

Users that can afford to pay for airtime over iridium rarely if ever use pactor.

With pactor you can do one thing... e-mail.

with Iridium you can
1. call home to say hello to family and friends on special occasions
2. call 911 as you abandon ship into your life raft and discuss the matter in person with emergency management personel.
3. receive voice calls (caller pays if they initiate the call)
4. receive free 160 character e-mail SMS mesgs
5. do all of your e-mail (compression based software highly recommended)
6. receive all of your weather (compression based service highly recommended).
7. browse the internet in a pinch...

you can do this any time day or night anywhere on the planet. The phone consumes 400 mAmps when running so power is never an issue. Installation is easy and requires that you plug the phone into a USB phone of your PC. Put the phone in a location where it can have a clear view of the sky. That is it. Simple as 1 2 3.

With HF... well lets not go there. Let just say that installations can be lengthily, expensive, disruptive, and problematic.

Anyway... that is my 2 cents worth... And BTW... you might say that I don't know what I am talking about with pactor and HF but I ran 2 stations on the XNet association (TN and Puerto Rico) in a network of 7 stations that ran pactor III exclusively for 5 years... the 1 - 5Kbyte per minute figure comes from sitting in front of computers running bench marks day after day year after year over the network and also dealing with customers and monitoring their traffic.

Take my word for it... Iridium is MUCH simpler and faster to use than pactor...

Iridiums throughput can be much higher than 9600 baud with compression. It just depends on what you are transmitting. Here is a sample from our logs where a user transmitted 70070 Kbytes which compressed down to 3.2Kbytes (ie 25X compression) in 15 seconds... (which is typical for iridium).

Wed Sep 29 15:58:44 2010 [83610-1285775919] cmd: "xsend client.x.bz2 3255 0"
Wed Sep 29 15:59:07 2010 [83610-1285775919] Relaying file=client.x size = 70070

For this one transfer the effective baud rate was 52kbs. It all depends on the compressibility of the date.

BTW... i have used pactor modems and HF radios for sale if anyone wants them.

take care.

--luis
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Old 01-10-2010, 17:49   #13
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One more thing... I don't want to leave the impression that 25X is typical for compression when transmitting email. This was an exceptional case. I like to say that

on average you can transmit 10 2-10Kbytes mixed text/html e-mails in one minute of iridium airtime. That is typically you get 3-5x compression in the block of e-mails. The more e-mail in the block, the better the compression, the better your efficient throughput.

For example... if you send one 1kbyte file you will get about 50% compression. That is the compressed e-mail is about 500 bytes. If, however, you send the same e-mail 1000 times the compressed block is a bit over 1Kb total! So your effective throughput for sending 1000 emails in this case is about 10 mbits per second. This is a very extreem case but it makes my point.

--luis
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Old 01-10-2010, 21:03   #14
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In case you don't believe Luis' numbers -- after all he runs GMN and has a vested interest -- as a person who uses both Iridium/XGate and SSB/Pactor3/Sailmail I can say that his data rings true to me.

My time to transfer GRIB data and text email is typically much faster using XGate. Sailmail limits the size of attachments so I seldom use it for larger files, but in the cases where I can compare Iridium/XGate wins every time. I really only use Sailmail to make sure it will be available as a backup, and because sometimes people send mail to my sailmail address.

Sailmail is probably less expensive, and ham-based Winlink is free, once you have all the gear. Iridium/XGate is more reliable and faster. To do practical everyday web-surfing you're going to want something faster than any of these.
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Old 02-10-2010, 02:00   #15
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skyfile

While reading all the info I can find in order to take my decision I noted that nobody mention Skyfile
It is not this similar compression software/service as XGate ? The big advantage is that it is free. Anyone has previous experience?
The other question is; there is any preferred provider where to buy airtime/contracts for Iridium? Are price standard? Worldwide?
thanks, Flavio
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