Our methodology for testing satellite communication devices and emergency locator beacons mirrors that of our other categories. Specifically, we test equipment, first and foremost, with an attuned awareness of how the equipment will actually be used. We do our testing in the field and in more formalized “lab” tests. With emergency messengers, because of the blessedly rare nature of actual emergencies, some of our conclusions are theoretical and based on fundamental understanding instead of direct experience. We aren't engaging the entire emergency messaging chain of command for each device, as this would be an illegal waste of resources. Otherwise, all of our conclusions are based on informed application and testing.
SOS/Emergency Messaging
Some messengers only do emergency messaging. For those, we have to rely on internal test procedures and on an understanding of the underlying theory. Others use the same underlying technology for emergency messaging as they do for the SOS functionality. In those, we can make some extrapolations about the emergency messaging function. In none of our testing, nor in the non-testing experience of any of our test team, have we actually employed emergency messaging capabilities.
Non-Emergency Messaging
For those devices that include non-emergency messaging function, the best testing is in sending and receiving routine messages from the field. Whether on the device itself or through a smartphone app, we are able to deduce the reliability and usability of the non-emergency messaging function of each product. We look for simplicity of text entry, options for text entry, and clarity of message delivery.
Signal Coverage
We have used satellite messengers all over the world for decades now. Since the nine products we tested use just three networks, we can pretty quickly deduce each new product's signal coverage. To correct for hardware differences, we test new products next to older, proven options on the same network. In this sort of testing, for what it is worth, we have found no difference between different pieces of hardware on the same network. The network makes a bigger difference than the brand, size, or type of messenger device.
Ease of Use
We simply used them. In setting them up, using them in tough situations, and navigating various maintenance procedures, we are able to notice issues and patterns in each product and service's utility.
Portability
First, we carried all of them around on a variety of human-powered adventures. Then we measure them, weigh them, and note each product's waterproofness, ruggedness, and carry options.
Conclusion
Our thorough testing and deep experience with this category of product allows us to make authoritative conclusions on what will work well for you. We put in the hours, based on years of background, to construct reviews that are most useful to you and your needs.