The HAZ Forums frequently feature questions about emergency transmitters and locators.
Since technology changes quickly, previous discussions become outdated. Researching older threads can be helpful, but it is also nice to find the most current information with ease. Let's keep discussion on this topic in this thread. It will be archived and a new thread started when new technology changes the game again.
Satellite Emergency Notification Device
Personal Locator Beacon
is the simplest to explain because it really only does one thing. It is used exclusively in an emergency and sends a signal on a global emergency network that can only mean one thing. You need help and need it now. Part of the data it transmits (besides your location) is identifying information so rescuers know WHO you are ahead of time. An additional feature of the PLB is that it has a local homing beacon, so when rescuers arrive to the area (100 meter accuracy) you transmitted from, the beacon on your device directs them to your exact location. This could be useful in heavy brush, etc.
PLBs cost more to purchase, but there is no subscription required
. The battery generally lasts for 5 years or so, and replacing it currently costs about $150. But it's one of those pieces of equipment you hope to never use.
In the technical nitty-gritty of it all, PLBs communicate on a global emergency network run and monitored by governments. PLBs transmit at about 5 time the power of other tranmitters. For pure emergency locating, PLBs simply have no competition.
The most popular brand of PLB is the ACR ResQLink
(there are several versions).
s on the other hand are generally used to communicate via satellite -- In emergencies AND non-emergencies. SENDs provide extra features that some users desire, primarily the ability to send "peace of mind" messages to loved ones, or other features including mapping, tracking and waypoints. For those users, SENDs are extremely popular options. But --SENDs require fee-based subscriptions
to transmit communications. Let's break them down into ONE-WAY and TWO-WAY communicators.
ONE-WAY communicators allow the user to send messages to the satellite network that are then delivered to pre-determined users. Emergency signals are forwarded to rescue personnel. Non-emergency messages can be simple messages such as "I'm OK" and are sent by text message or email to family or other pre-designated users. Some devices send only pre-programmed messages, while others will pair with a smart phone and allow custom messages to be sent. An example of a one-way SEND is the SPOT Gen3
TWO-WAY communicators do everything that ONE-WAY communicators do, but also allow the user to receive messages
over the satellite network. This can obviously be helpful both in emergencies and non-emergencies. An example of this kind of SEND is the DeLorme InReach
In the technical nitty-gritty ... SENDs transmit their data to commercial satellite networks that do not always have global reach. This is why they require a subscription fee. DeLorme uses the highly-reliable Iridium satellite constellation and SPOT uses the similar Globalstar constellation. The messages are received by a third-party and then forwarded to the appropriate entities. Think of it as On*Star for your hike! They transmit with a power level that is only about 20% of that of a PLB. This makes them more susceptible to not acquiring your location, or not sending a message when desired.
I should add that I don't personally own one of these devices and what is written here is just a brief summary of my research. I'll gladly correct anything that is incorrect. But feel free to discuss this topic here and include your own information, experience, and knowledge.
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