Are Satellite Messengers a Good Alternative for PLBs?

We take a Personal Locator Beacon (PLB) with us every time we go into the back country and when we drive on isolated roads. PLBs are small portable transmitters capable of sending distress signals that can be received by the international Search And Rescue Satellites (COSPAS-SARSAT). PLBs will summon help where cell phones are useless.

Our PLB is the simplest version and is designed to do only one thing. If we ever need help in a remote area without cell service, we simply push “the button” and it sends a signal with our location to the satellites, where someone at Langley Air Force Base will notify the closest Search and Rescue team to our position. Because we have registered our PLB, they will know who we are, where we are and that we are asking for help.

When I am out by myself, my wife feels better knowing I have the PLB, but it would be nice to be able to send messages home. If I decide to spend an extra night out and if I am out of cell phone range, I can’t let her know. It would also be very useful to be able to send text messages like “Elk Down. Come to right fork trail head.” And if you ever had to send an SOS message, it could be critically important to have two-way communication with the rescue team.

Learn more about how PLBs and SAR works and read My “I Wish I had a PLB” Story

More examples where PLB could have saved lives or reduced suffering

When we bought our PLB about three years ago, we also looked at more advanced PLBs and alternatives such as Satellite Messengers and Satellite Phones. At the time, we couldn’t justify the cost for a satellite phone and the Spot Satellite Messenger appeared to be too unreliable for sending SOS message and too many people were very unhappy with the Spot subscription service. So we bought the simplest, least expensive PLB so we would be able to call for help if needed.

Since it has been three years and technology changes so fast, I thought I should do a little research and see if anything had changed to make more advanced PLBs or satellite messengers more attractive than our simple, but reliable Fast Find PLB. So, what are the options?

Satellite Messengers – Satellite Emergency Notification Devices (SENDs)

SENDs are a private subscription services that use private satellites, like Global Star and Iridium for one or two-way email and text messaging (with GPS location) and to send SOS distress signals.

There are basically two companies fighting for the satellite messenger market, Spot and Delorme (bought by Garmin).

ACR’s 406Link Service

ACR Electronics makes several models of PLBs and have developed the 406Link Service that uses test signals sent from a PLB to the satellites to send emails or SMS messages. When you test the PLB, ACR sends your preset message to your email or phone list (1 – 5 contacts) so your family or friends know you’re OK.

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Certified PLBs:

The ACR 406link service will work with many of ACR’s older PLBs, but there are limitations due to the drain on the battery. Since the primary purpose of PLBs is for making emergency SOS calls, the number of self tests and GPS tests is limited to make sure there is sufficient battery power for emergency signals to be sent for the mandated 24 hour minimum.

The ACR 406link service works best with ACR ResQLink, AquaLink and SARLink models designed for between 220 – 440 self tests, meaning the same number of messages can be sent. These models can also perform between 12 – 60 GPS tests so those messages can include GPS coordinates.

So, between Spot, Delorme/Garmin and the ACR 406Link service, there are now several options for email and/or SMS text messaging. In addition, there are some additional features the technology makes available.

Features of Satellite Messengers and ACR 406Link Service

  • SOS – Emergency Calls
  • One-way email or SMS text messaging
  • Two-way SMS text messaging
  • Tracking/Sharing
  • Roadside or Marine assistance

SOS Emergency Calls

PLBs and Sends can both make emergency calls for help, but they work in different ways.

PLBs use powerful (5 watt) 406 MHz signals that are received by the international COSPAS-SARSAT system and are relayed to Langley Air Force Base, who notifies the closest Search and Rescue team. Regulations require that PLBs be able to transmit for at least 24 hours. They also simultaneously transmit on the local Search and Rescue (SAR) frequency (121.5MHz). No subscription service is needed for this service, but in some cases, you may be charged for the actual rescue.

When emergency calls are made on Spot (400 milliwatts) or Delorme (1.6 watts) SENDs, they go to a call center which then notifies local 911 (112 in Europe) with your GPS location. These private services requires an annual or monthly subscription and may not work if your account is not current unlike 911 calls that still work on delinquent cell phone accounts. Delorme sends a confirmation message, so you know the SOS has been received, but Spot does not.

One-Way Messaging

spot messenger and g3

Spot Messenger and Spot Gen3

One-way messages are preset messages sent via email or SMS (text) to pre-arranged recipients. This service requires an annual or monthly subscription service available from Spot (Spot Messenger & Spot Gen3) and Delorme (InReach, InReach SE & InReach Explorer) and for PLBs with ACR’s 406Link Service.

Messages are created after setting up an online account, where you create or select the message(s) you plan to send and create and email list or phone numbers you want to receive the message. You have to do this ahead of time at home and can not do this in the field. The Spot system allows for one preset message in addition to one or two custom messages limited to 41 characters.

The “Check In/OK” message simply states something like this:

John Latitude:38.29727 Longitude:-111.59591 GPS location Date/Time:08/12/2014 12:17:33 PDT Message: John is OK and Checking in. Click the link below to see where I am located“.

Everyone on the list is supposed to receive this message when you push the “Check In/OK” button if the GPS location can be determined. Every time you push the button, everyone on your list gets the same message and can see your location on a Google Map when they click the link.

Satellite Messengers:

A custom message is sent when you push the “Help or Assist” message and can read something like this: “I am ready for pick up” or it could be something like my “Elk Down” message above. This message also has to be created on-line ahead of time and would be intended for only one or two people that you already made arrangement with.

The Spot Gen3 allows a 2nd preset custom message that can be used as a different Check In type message intended for a different contact list or it could be a special request for help message like “Elk down”.

The problem with these messages with the Spot network is you never know until you get back and talk to the recipients if the message was ever sent or not.  Same is true for the SOS signal. Many people have sent thousands of messages and many have even been rescued using the Spot SOS system, proving the system worked for them, but you will never know if the message was actually sent or not.

Two-Way Messaging

deloreme se and explorer

Delorme SE and Delorme Explorer

Only Delorme (bought out by Garmin) offers two way text messaging (for a fee) with the InReach SE and InReach Explorer models. They allow 160 character text messages to be sent and to be received. Delorme/Garmin also allows preset messages to save time texting, which is probably a good idea if you don’t marry the messenger to your smart phone via Delorme’s Earthmate App., because according to many reviews, texting is awkward using the virtual keyboard. But awkward or not, the ability to send and receive text messages in the middle of no where can be very valuable.

To send messages, you will first need to create an account (MapShare page) and create a contact list. You will also need to send the link to the MapShare page to your contacts so they will be able to contact you if you haven’t sent them a message first. After you have sent someone a message, they can reply.

The original InReach Model was very problematic, with issues like text messages getting cut off with advertising, clunky updates and problems syncing with smart phones, but many of those original problems and complaints associated with the new device appear to have been fixed. In addition to SOS and texting ability, the InReach Explorer also acts as a GPS unit so you can create and find way points. The GPS function also appears to be clunky, especially for people that already use other more modern GPS units.


The tracking function allows friends and family to log-in to your account to see your current location and to track your progress through the wilderness or through foreign countries. This service is also requires a subscription and is available to varying degrees from Spot, Delorme and the ACR 406link Service for PLBs.

By varying degrees, I mean different pinging rates. Most people will find that upgarmindates every 10 minutes are enough for someone to follow your progress and both Spot and Delorme can do that with basic plans. For those that want more real-time updates, Delorme/ offers updates every two minutes and Spot every 2½ minutes, which are better for creating fine grained tracks.

Delorme/Garmin also offers the ability for your followers to log in and actually ping your latest location and with both Spot and Delorme/Garmin, you can share your messages and locations on Facebook or Twitter.

ACR’s 406link service also offers tracking, but because batteries must be conserved for the mandatory minimum 24 hour SOS signal, individual pings are limited to between 12 – 60 pings depending upon the ACR PLB model.

Roadside or Marine Assistance

Spot also offers a roadside/marine assistance service similar to General Motor’s On Star system. For an additional fee, they will call someone to come to your non-emergency rescue with tow service, fuel, tire or battery delivery service, lost key or lockout service.

Read More

With the addition of Garmin InReach and ACR’s 406Link service, there are two new options for satellite messaging that were not available a few years ago.

This is the first in a series of four related posts on comparing PLBs and satellite messengers. To follow the entire discussion read the following articles:

Read more about PLBs:

Comments, Opinions, Questions?