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WorldEmail at SeaSatphone

Satphones (and others)

Iridium 9575 Extreme Satellite Phone

Satellite phones offer various services, including internet connectivity and voice communication, over one or more satellite networks.


One of the issues with satellite technology is that you have to purchase two separate components, often from different service providers. These are:

  • Phone, modem, and/or other hardware, from a satellite phone or equipment retailer.
  • Telephone talk time, broadband data, or other services from a satellite service provider.

Because talk time is usually sold through retailers, it's more common to purchase a bundle of a satellite phone, SIM card and talk time through one single retailer such as GMN or Cytech Communications.

Comparatively, satellite phones for voice usage are cheaper than HF radio sets, and satellite communication gear to connect to, say, a laptop PC for internet connectivity is cheaper than a Pactor-style HF modem, however satellite data charges are more expensive than sending your data over HF.

Generally speaking, you would purchase a satellite phone from a specific manufacturer that was compatible with their plans. For example, the IsatPhone Pro from Inmarsat to use Inmarsat plans, and the Iridium Extreme from Iridium to use Iridium plans, which are the two most popular choices at the moment (as of February 2014).

A satellite phone retailer would be able to provide you with a phone, a SIM card, and a plan to match the phone.

Service Providers

To be a satellite service provider, a company needs to have one or more satellites orbiting the planet. Obviously, that's not a cheap business to get into, and so world-wide there aren't many of them. The main service providers are:


  • Cytech Communications sell a number of brands of satellite phones, in the USA.
  • GMN also sell a range of satellite phones, plans and services.
  • TC Comms an Iridium/Inmarsat dealer in Australia
  • SmartCom - software for easy internet access by mobile or satellite phone
  • PC SatC - software for use with INMARSAT C systems

Call/Data Plans

For the most part, call / data plans have to be purchased from one of the satellite providers via one of their dealers. These dealers tend to package the airtime plans in different ways, e.g. Cytech Communications who sell prepaid blocks of minutes, with various (number of months) expiry times, at different prices.

In addition to the Call/Data plan, you will need a SIM card. This is normally provided with the first call/data plan that you purchase.


With Iridium plans you generally purchase a number of minutes of satellite air time which is then broken down into seconds. If you need data then you connect to the Iridium data gateway using your satellite phone as a modem, by calling a specific number and making a data connection. The data that you download is not charged for, only the connection time (and obviously a lot of data can use a long connection time, and therefore make a dent in the number of minutes that you have purchased).

An SMS message or email message (email sent direct from the phone not via an email client on your PC) sent over an Iridium network using pre-paid minutes generally uses a few seconds of airtime. The Iridium phones that can send position updates via email use one second of prepaid airtime to send each position update.

Most Iridium dealers tend to sell prepaid blocks of minutes.

  • Iridium -- you can't buy airtime direct from Iridium, contact one of the dealers below instead.


Inmarsat plans are sold as a number of units. Each unit is approximately 1 minute of call time, or a bit more than 0.1MB of data, or some combination thereof.

  • Inmarsat home page -- similar to Iridium, you purchase plans from a dealer, such as one of the following:
    • GMN sell IsatPhone Pro prepaid or postpaid units.


(update required -- the information that was in this section is now obsolete)

Setting a Satellite Phone up for Email

Iridium 9575 Extreme Satellite Phone kit with accessories

Things you will need:

  • A satellite phone or modem -- see the Equipment section above.
  • A data connection kit for the phone, this is generally supplied with the phone. There may be an additional docking cradle required, e.g. the Iridium 9575 phone pictured above comes with a docking cradle into which the USB cable can be plugged. This is usually a USB or serial cable that plugs into the satellite phone.
  • A satellite SIM card and some airtime. Generally the SIM card comes with the first block of airtime that you purchase, and the satellite phone number that you receive will be tied to this airtime. Check with the dealer of the airtime that you are purchasing to ensure that the SIM card is supplied. See the Call/Data Plans section above.

The picture to the right shows a typical satellite phone "kit" -- comprising the phone, charging cables and adapters, USB cable, external antenna, etc.

Note that once you have the above, you have a method of connecting your PC via the satellite phone to the internet. You will need some general modem/dialling software, for example wvdial or pppd under Linux, or the standard PPP software supplied with Windows or MacOS will do the job. However what you now have is a very poor and slow internet connection, so it may be of some benefit to get some additional software and/or equipment to make your life easier.

  • XGate software is specifically designed to work with satellite phones, and allows a limited amount of web activity (e.g. updating a facebook, twitter, or sailblogs account) as well as fetching email. It provides data compression to and from an email account set up on the GMN servers to a mailbox on your machine. It is cross-platform and works on Linux, Windows, Mac, and Android.
  • UUPlus is designed for Windows, Mac and Linux and provides an email gateway. It works over HF or satellite. I tried several versions of this software on Ubuntu Linux but I could not get it working -- Delatbabel.

Step 1 -- Plug it together

Most recent satellite phones have a USB cable to connect to a computer (older ones might have a serial port, some newer ones will come with Bluetooth). There will generally be a small USB plug on the phone, and the phone will come with a cable to connect between that port and the standard size USB port on your computer.

Some phones, for example the Iridium Extreme, will come with an additional cradle which has the USB port. Plug the phone into the cradle and then plug the USB cable between the cradle and your computer. The Iridium Extreme also charges via the USB cable (although the cradle also has a separate charging port).

If there is an external antenna for the satellite phone then you may want to plug this in as well -- for example one of the two cradles for the Iridium Extreme phone contains a jack for connecting the antenna, and the kit contains an antenna with 5m of cable. Plug the antenna into the phone (or cradle) and place the antenna out on deck where it has a clear unobstructed view of the sky.

Step 2 -- Test a data connection

Before going any further in terms of software subscriptions, etc, it is worth ensuring that you can in fact get a PPP data connection from your satellite phone to the internet. This is done by dialling a specific gateway from your PPP dialling software, which can vary depending on the satellite provider you are using, and the OS you are using (Windows. MacOS, Linux, etc).

As an example, there are a couple of sites that list methods to connect under Linux, and because these tend to be written by the more technical people they will give you some examples of how to connect:

Using the Iridium gateway, you set your PPP software up to dial the gateway phone number (008816000025), and connect using the login name "directinternet" and the password "directinternet". You will also need the following 4 init strings:

  • Init1 = ATZ
  • Init2 = ATS0=1V1X4E1Q0&c1
  • Init3 = AT+cbst=71,0,1
  • Init4 = AT+cr=1

Once you have a data connection, your PC should have obtained an IP address via PPP and you should be connected to the internet. It won't be a useful connection for now, but it will be a connection. Also be aware that the connection is burning through your satellite minutes, so as soon as you are sure you have one, disconnect!

Step 3 -- XGate Software

A simpler setup will be to download the XGate software from GMN. This has the following features:

  • Sets up your PC to dial the internet via the satellite phone (or can connect directly if you are in wifi range or similar).
  • Sets up a local mailbox for you to send and receive mail.
  • Sets up a synchronisation between your local mailbox and the XGate server so that you can read mail, send mail, then make one connection to the internet to send and receive all mail (with data compression) between the two.

Using the XGate software is as simple as downloading it and installing it. You can obtain a free 3 day trial of the XGate software which you can set up with or without the satellite phone, and evaluate it for your own use. Should you decide to proceed, a monthly subscription can be purchased.

The XGate software already contains a PPP dialler pre-configured to correctly connect to the various satellite gateways -- Iridium, Inmarsat and others, so if you want to skip step 2 and move directly to this step then you can do so.

Step 4 -- Configuring your Mail Program

The XGate software is designed to work with Thunderbird and if it detects that mail program installed on your system it will configure it to talk to the XGate client. If it does not then it's a matter of configuring Thunderbird manually, or your own preferred mail program. (TODO).


Publications, etc.

  • Yachting Monthly's Using PCs on Board - good coverage of using your PC and mobie or satellite phones for communications


List links to discussion threads on partnering forums. (see link for requirements)



We welcome users' contributions to the Wiki. Please click on Comments to view other users' comments, add your own personal experiences or recommend any changes to this page following your visit.

  • Delatbabel -- I opted for an Iridium 9575 Extreme satphone, a call plan from Cytech Communications, and a subscription to GMN XGate, to allow email at sea instead of an HF / PACTOR Modem system, in November 2013. So far it has worked well. My HF Radio was an older ICOM M600 model which was not compatible with the PACTOR modem, hence upgrading to PACTOR would have required replacing the HF Radio. I don't have a HAM license and so WINMOR was not an option.

This page has an outline in place but needs completing. Please contribute if you can to help it grow further. Click on Comments to suggest further content or alternatively, if you feel confident to edit this page, click on the edit tab at the top and enter your changes directly.

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Names: Delatbabel

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