Worldwide Satellite Comms
February 3, 2020

Molly has three types of satellite communication, each with its own features and benefits. Let’s get into the details of each of these.

isatPhone Pro and dock for voice communication over the Inmarsat network.
SPOT Trace tracking us over the Globalstar network.
Garmin inReach Mini used for tracking and emergencies over the Iridium network.
Voice Communications via Sat Phone

Molly is old school, with an Inmarsat based Sat Phone. Inmarsat actually put its first satellite into orbit in 1976, although the current generation of satellites is from the mid 2000’s. We have owned our Sat Phone for many years, but with Molly we made some significant improvements. On our previous trip the Sat Phone was hidden away, to be used when it was needed. This approach meant it was used only for making outbound calls.

In Molly the Sat Phone is permanently mounted in the docking station with a connection to a high quality external satellite antenna, mounted high on the roof with good visibility of the skies. This new arrangement provides better connection to the Inmarsat network, but more importantly, is powered on whenever we want. This always-on approach means we are constantly confirming that we can register with the Satellite network, and, also means others can calls us. We are currently subscribed to the cheapest, low-call-volume monthly plan we can find – which is a good solution for us – in the rare event we have to make emergency calls.

Tracking via SPOT

SPOT is our vehicle tracking device, connected to a satellite service based on the Globalstar network. This means Molly’s movements are constantly being tracked in real-time. When the device detects movement it sends a short message every 10 minutes with its current location to the Globalstar network. Our SPOT device is the Trace model, which is a one-way tracking device, and can only transmit tracking points up to the satellites. It is not possible to receive messages (at least not messages we can see).

With some software we wrote, we are able to query the Globalstar network and automatically create maps of our journeys from the tracking points sent.

Messaging via Garmin inReach

We have two Garmin inReach Mini devices that can send and receive messages via the Iridium satellite network. These are small portable devices that we use when we go hiking, and, they also have an interactive SOS feature, which can be activated in the event of a life threatening emergency. The Garmin inReach can request and receive weather forecasts, a particularly useful feature when travelling overland and internationally.

Like the SPOT tracker, we can query the Iridium network and automatically add tracks to our maps. We have not written the software to do this just yet, but we will.

Diversity Rules

Granted, we have more satellite technology than is typical, but each has its own function and benefits. Firstly, all three devices use different satellite networks, providing nice technology and network diversity. Secondly, each device performs well at one specific function: the Sat Phone for voice, the SPOT Trace for vehicle tracking and the Garmin inReach Mini for messaging.

This diversity results in three concurrent service or monthly subscription charges. We have the basic plan for each service, and for all four devices our total bill is less than $100 per month. This is a monthly charge we are happy to pay, as it is good insurance, knowing we can get help if we need it.

Coverage Maps

Iridium has total global coverage; Inmarsat doesn’t but covers everywhere we want to go. The SPOT service has a few limitations, with no coverage in the southern tip of South America, but this is not a big deal, as the Sat Phone and the Garmin inReach devices are for safety and the SPOT is more for fun.

The bigger problem with international coverage is not the international coverage of the satellites. Rather it is our ability to cross borders with satellite based technology. Some countries may choose to take exception to our gadgets. We travelled all through Australia, South East Asia, Central Asia, Eastern and Western Europe and parts of Africa with our Sat Phone and never had a problem. But one day, some official is probably going to want to make life difficult for us and we may need to walk away from our Sat Phone. The only redeeming point is that our Sat Phone is old and not worth that much anymore.

On-line Tracking

Amazon provides a cloud based computer and storage platform where we host a small application that keeps track of us. Amazon has a free tier and this application is small enough to stay well within this free tier. Every 5 minutes the application will talk to the SPOT servers and get the last 50 tracking points sent by the SPOT Trace device. The application then cobbles together all of these tracking points and creates an online map laid on top of Google maps.

The above map was auto-generated from a combination of SPOT Trace tracking points and manually entered points.

Tracking points are shown as red pins and these come from SPOT. Other points of interests, like camp sites, scenic viewpoints or eating places, can also be added to the map by sending a message from a Garmin inReach or iPhone (if in wifi or cell coverage) with a keyword and a short description to be indicated on the map. This way we can add to the map by sending the application a short message. Thus our on-line map is able to track us in near real-time, even if we have no Internet coverage. This tracking is achieved with very little effort while we travel.

Icon Keyword Purpose


Tracking Point


Camping in Molly


Scenic Viewpoint


Fueling Station


Garage for Repairs


Point of Interest


Information of Interest


Wifi Available


Restaurant or Cafe


Hotel or other Accomodation

Last Known Position

With the Garmin inReach we can send the message “Food Ahwahnee for Coffee, and the above point is automatically added to our map.
Beam Communications IsatDock ISD720 Transport Bolt Active Antenna is designed for transport /land based applications.
The isatPhone Pro in the Beam Communications IsatDock LITE (ISD LITE)
Making first test call with the Sat Phone. All working well.
Out hiking with our Garmin inReach.