The SPOT Messenger and Personal Locator Beacons

10 November 2009

Until recently I had never heard of the SPOT. I was familiar with the Personal Locator Beacon, or PLB, but  I had never considered using one.  As we sat around the campfire during a recent North Wash canyoneering trip, people talked of their experience with SPOT- how well it messaged, how they used it for pickup at the end of their treks, how it kept their families happy knowing they were safe, and how it creates an online GPS coordinate database of the ground they cover.

The SPOT sounded interesting, but I have always been one to leave technology behind when going into the wilderness. I have never carried a cell phone, any type of two-way radio, or even a GPS in the bush. For more on my thoughts on the GPS, see my recent blog post . But after listening to peoples’ experiences with SPOT, after doing research for a blog post on rattlesnakes, and after reading recent news articles regarding the use (and misuse) of SPOT and PLB’s  (see Ramkitten’s collection of articles) I have been thinking more about how I could use the device.

The safety of my five year old has also prompted me to take a closer look at the SPOT and PLB’s. In recent years my son and I have been spending more time together in the Utah desert. Rattlesnakes have always been my greatest concern in the bush, and I seem to meet up with them frequently enough. Now that my son is along with me, that concern has become heightened. If keeping him safe means merely carrying another 6 or 8 ounces in my pack, then that is easily done. There is no question that these devices save lives, and are worth their weight and cost during emergency situations.

SPOT,PLB’s, and Avalanche Beacons


The SPOT Satellite GPS Messenger (SPOT 2)- 5.2 ounces without batteries (about 6 ounces with lithium batteries), cost- $149.95 at REI for the device and $100.00 per yer activation fee for basic features.

Being relatively unfamiliar with both SPOT and PLB’s, I began by seeing what REI had to offer.  REI carries a number of PLB’s and both versions of SPOT including the new, SPOT Satellite GPS Messenger,  the ACR SARLink 406 PLB, and the McMurdo Fastfind 210 PLB. Both ACR and McMurdo have a complete line of PLB’s and related survival equipment for all types of outdoor activities.  Do not confuse these devices with avalanche beacons, or transceivers, which are a separate device altogether.  Avalanche beacons transmit a homing signal locally, so that others with a transceiver are able to pinpoint a person’s exact location under the snow.

Common Features

In my research I focused my attention on devices for “land-based” activities- hiking, backpacking, floating rivers, and biking for example- where you might find yourself far from help. The information I provide comes from the spec sheets for the respective devices and phone calls to customer service for each.  Speaking of customer service- I spoke to representatives at SPOT and  ACR  immediately after placing my calls.


The ACR SARLink PLB- 8.9 ounces with battery, cost- $399.95 at REI (no yearly activation fee).

For purposes of presenting SPOT and a PLB, I chose to focus on the ACR SARLink and the SPOT Satellite GPS Messenger.  Should you use either one to call for help, both devices use GPS satellites to find your location and then transmit those coordinates and a distress call to other satellites, which in turn transmit them to a call center. A distress call using the ACR SARLink goes through the government’s SARSAT system, ultimately ending at their control center in Maryland. When you register your ACR SARLink you are given a unique identification code which allows rescue personnel to know exactly who you are so they can seek additional information about your situation. The ACR SARLink transmits a local 121.5 mhz homing signal (line of site), much like avalanche beacons, to search and rescue personnel in your vicinity. The SARLink also has a built in LED strobe.

Unique SPOT Functions

Activating the SPOT S.O.S. function will send your GPS coordinates and distress call through a commercial satellite to the GEOS Alliance, a private company in Texas. In Tracking Mode the SPOT will retrieve your coordinates every 10 minutes and store them on your SPOT personal web page for 30 days. This page can be shared with friends and family. The coordinates can be exported and saved in Excel or Google Earth formats. The Track function continues for 24 hours after the Track button is depressed. You must reactivate the Track function every 24 hours.

Using the Check-in function you can send your present coordinates and a custom message to up to 10 email addresses or phone numbers as a text message. Using the Custom Message function you can create a different message to be sent to the same or other email addresses or phone numbers.  Finally, you can create a custom “Help” message for up to 10 contacts- this can be used to notify contacts that you are at a resupply or pickup location, for example.

Cost and Activation Fees

There is a difference in the initial cost between the two devices. PLB’s are more expensive across the board than SPOT.  But it is important to look beyond the initial cost of the device.  You will spend 400 dollars on the ACR SARLink. You will spend 150 dollars for the SPOT Satellite GPS Messenger.

To keep your SPOT active and to use the basic functions- S.O.S., Help, Check-in, and Custom  Message- costs another 100 dollars per year. Additionally you can choose to pay $7.95 for yourself and each family member, per year, which covers up to $100,000 for each individual in search and rescue costs (see the GEOS Alliance website for full details). The Track function costs $49.99 per year, Road Assist can be added for $30.00 per year, and replacement insurance for the unit can be added for $17.95 per year.

There is a one-time activation for the SARLink, and that is included in the initial cost of the device.

Batteries and Battery Life

The ACR SARLink uses a proprietary lithium battery that is costly. A replacement battery for the SARLink will cost around 160 dollars, not including shipping. The battery only needs to be changed every 5-6 years, or after emergency use of the device. The battery change should be done by an authorised service center where they will also verify the seal on the unit, reset the battery use indicator, and perform a number of tests on the unit to insure that it is ready for use. Battery life in emergency mode is rated at about 35 hours.

The SPOT uses 3- AAA lithium batteries, available at your local grocery store for about 7 dollars (the first generation of the device uses 3-AA batteries). The use life of the batteries in the SPOT depends on the operation of the device. In tracking mode you will get about 14 days of use on one set of batteries. If you use the message functions- the Help, Check-in, or Custom Message function, you can send up to 1900 messages on a set of batteries.  So if you use the Tracking function and send a message or two a day, you can probably expect to change the batteries every 10 or 12 days.  The SPOT will send a  message every 5 minutes for 7 days in the S.O.S. function.  All of these time estimates are assuming new batteries.

Waterproofing and GPS Accuracy

Both devices are rated waterproof to 5 meters in depth for 1 hour. You could safely swim with either for extended periods, for example making your way out of rapids or swimming across a river.

There is a difference in GPS accuracy in the devices. The SPOT is accurate to about 6 and 1/2 meters.  The SARLink is accurate to within 100 meters.  The homing feature on the SARLink more than makes up for its being less accurate than the SPOT.


According to the SARSAT/NOAA website, there were 282 rescues in the United States in 2008 initiated through SARSAT. Of these, 68 people were rescued in 35 incidents using the PLB to call for help. No further details were given about the rescues. You can read a few ACR PLB rescue stories at the ACR website.  According to the GEOS Alliance website, 400 people were rescued using the SPOT to call for help in 2008. No details were given regarding the number of incidents involved. You can read about some of the SPOT rescues at the SPOT website.

After researching the SPOT and the ACR SARLink, I cannot say that one is a better choice than the other. If you are looking for peace of mind in the form of 6 or 8 ounces, you have found it in either device.  If your goal is to carry a device to call for help in the event that rescue is needed, the PLB will suit your needs.  If you are interested in communicating your location daily, and tracking your progress in the wilderness, then the SPOT is for you.

Ultimately one of these devices may save your life, but they are not a license to act without caution.  A PLB or SPOT is not a substitute for knowledge, preparedness, or common sense.  Recent unnecessary SPOT distress calls may signal the need for a closer look at who pays for search and rescue costs. Proper use of these devices by everyone will keep us all safe at a reasonable price.