Global Marine Networks Blog

IsatPhone or Iridium Cheaper for Gribs at Sea with Mac iOS?

  

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Recently we were contacted by a cruiser that wanted to get GRIB files onto his iPad over a satellite phone while at sea. He was looking for the least expensive way to do this. Knowing the Isatphone Pro handset costs less than the Iridium 9555 or Iridium Extreme, he had some questions:

1) Could he get GRIB files onto his Ipad with the IsatPhone Pro

2) How long it would take for a typical GRIB file download, and

3) How should he compare the total price of hardware and service between the IsatPhone Pro and Iridium offerings? 

Excellent questions and here are the answers:

1) Yes, You can download GRIB files to your iPad (or any iOS device, like an iPod Touch or iPhone) using an IsatPhone Pro - with the Optimizer satellite firewall and Wi-Fi hotspot

What You Need:

1. an IsatPhone Pro
2. an iPad or other Apple iOS device
3. either iNavX or Weather4D weather software
4. an Optimizer satellite firewall and Wi-Fi hotspot
5. XGate satellite email service App

You can use the identical setup with and Iridium phone, or a similar setup with the Iridum AxcessPoint and Iridium AxcessPoint Mail & Web App. 

 Let's look at the elements of this:

- Optimizer's firewall ensures that all of the very narrow IsatPhone data feed is available.

- Optimizer's Wi-Fi hotspot allows the iPad to connect to the data feed.

- iNavX and Weather4D work with XGate so when you request a GRIB file, the request is sent to XGate. 

-XGate then sends the GRIB file request as an email, and receives the reply email from the GRIB file provider. 

How Long Does It Take to Download a GRIB File over a Satellite Phone?

There are two calls that need to be made - first the request, then the download of the file. The first call can generally be done in the minimum calling increment of the satellite service: 

IsatPhone minimum calling increment: 1 minute

Iridium minimum calling increment: 20 seconds

Then, you can look at the time it will take to download the reply email from the GRIB service (For this example, we are using a 3 day GRIB File with 12 forecasts of wind every 6 hours arrows every degree for the size of the Caribbean sea)   : 

When using the IsatPhone it takes a full minute to bring up a connection on an IsatPhone before you start downloading data.  Once connected you can transfer about 12Kbytes of data per minute.  A typical GRIB file is about 15Kbytes. So, it takes a bit over a minute to download this grib file on an IsatPhone. 1 minute to connect + 2 minute of airtime to download (one minute plus a few seconds is billed as two minutes) = 3 minutes of airtime

IsatPhone Pro billing time to request and receive a GRIB file: 4 minutes  

Iridium runs a bit faster: 18Kbytes per minute on an iPad is routinely seen. It takes 20 seconds to get connected to the network and the billing increment is 20 seconds.  So you are looking at 4 billing increments, or 1.33 minutes,  to download the same file.  

Iridium billing time to request and receive a GRIB file: 1.66 minutes  

How Much Does It Cost To Request and Recieve a GRIB File? 

Based on some typical airtime plans, let's do the math to compare pricing. 

Lets assume that you your have a 100 minute prepaid airtime plan for IsatPhone... the retail price for this is $99 or $1 per minute.  In this case:

IsatPhone airtime costs to request and receive a grib file: $4.00  

For an Iridium user with a 500 minute plan the cost is $1.29 per minute or .43 cents per billing increment. In this case: 

Iridium airtime costs to request and receive a grib file: $2.15

Total Cost of Ownership

Baseline costs: the IsatPhone costs about $595 and the Iridium 9555 costs $1,195. However, additional hardware such as a dock or external antenna, must-haves for most boaters, will eliminate any hardware pricing advantage. The options are complex, but should be called out. A firewall/Wi-Fi hotspot is required for either service and should be factored in. 

Additionally, your time has value - if you're staring at your screen waiting for a download, is that worth the $1.85/minute difference in this example to you? Maybe, maybe not. 

The short answer is that for heavy data users who will be using their service for years, the Iridium solution is preferred due to the extra speed and lower price for airtime. For light users or those who will only be out on the water a limited time, the IsatPhone Pro will likely cost less depending on accessories, and will certainly work well when paired with Optimizer. 

Take Away:  Yes, you can download GRIBS at sea over your IsatPhone Pro or Iridium 9555. Contact us to help you compare total costs. 

Please contact us if you have more questions!