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ARC MicrOFix GPS Personal Locator Beacon

ARC Microfix GPS Personal Locator Beacon

I do a lot of solo backpacking in some out of the way places and my wife, understandably, worries about my safety. This year she asked me to bring along a Personal Locator Beacon (PLB) on my more remote trips where a serious injury, like a broken femur or a bad fall could be fatal. I agreed immediately: she gives me the freedom to go on my wilderness jaunts and her concerns are justified. This doesn’t mean that I’ll bring a PLB on all of my trips: just the ones that are way off-the-grid and I’m unlikely to meet anyone for days at a time.

As a long distance backpacker, the most important purchase criteria for me was international portability with minimal hassle. I have a 170 mile trek coming up next spring across remote mountainous parts of Scotland and I want a little extra safety insurance on that trip. Additionally, I wanted a unit that was as lightweight as possible without a loss of functionality, idiot proof to use, and NOT prone to accidental activation or false alerts.

This last item is a serious issue with some devices. Accidental activations put Search and Rescue personnel and resources at risk and waste valuable resources that someone else might need in an emergency. Personal Locator Beacons are serious rescue devices and should only be used as distress signaling device of last resort for use when all other means of self-rescue have been exhausted; where the situation is grave and imminent, and the loss of life, limb, eyesight or valuable property will occur without assistance.

During my product evaluation process, I did a lot of research about personal locator beacons and how they plug into an international satellite network that mobilizes local Search and Rescue units. It’s fascinating and something you should understand before you make a purchase decision about a PLB.

We’ve all heard about the SPOT Satellite Messenger. If you’re thinking about buying one, I suggest you read the rest of this post first. It might help you reassess your purchase criteria.

When a personal locator beacon is activated in an emergency situation, it broadcasts a distress signal over the 406 MHz frequency to the COSPAS-SARSAT satellite system which triangulates its location and alerts local Search and Rescue authorities. COSPAS-SARSAT is an international satellite-based search and rescue system that has helped save over 24,000 lives worldwide since its inception in 1982. Sponsored by Canada, France, Russia, and the United States, the system locates transmissions from emergency beacons carried by ships, aircraft, and individuals.

Use of the COSPAS-SARSAT system is free to the beacon operator. Yes, that’s right: free. COSPAS-SARSAT publishes a approved list of personal, marine and aircraft beacons which are certified for use using the 406 MHz frequency. The SPOT Messagener is not listed here because SPOT uses a private commercial satellite network, not the one used by SAR agencies worldwide.

After purchase, every personal locator beacon unit must be registered with a National Authority. In the US, this is NOAA, the National Oceanic and Atmospheric Administration. In Canada, the National Authority is the NSS or National Search and Rescue Secretariat. Other countries have their own National Authorities. When you register your PLB, you provide personal and emergency contact information in case it is needed by search and rescue agencies. You also have the ability to enter details about your latest expedition and itinerary which is helpful for SAR units.

In the US, the registration process is online and you can update your information as often as you like if you take a lot of trips or want to transfer your device to someone else. The National Authorities use the information you enter to determine if an actual emergency exists. If your beacon is not registered, SAR authorities will not know who you are or who to contact to request additional information about your situation or medical history.

After I learned about COSPAS-SARSAT, I understood that the eastiest way to achieve international PLB portability was to purchase a device that used the 406 MHz network.  When I want to hike in a different country, I don’t technically have to do anything because all 406 MHz devices are already globally compatible. However, it is still advisable to update your itinerary information online with your National Authority, so it can be routed to local SAR units, if needed.

ARC Microfix GPS Personal Locator Beacon

After some additional research, I purchased the ARC MicrOFix GPS Personal Locator Beacon because it has an on-board GPS in addition to being 406 MHz compatible. When activated in an emergency, the Microfix inserts a GPS packet into the 406 MHz transmission with your GPS location and then updates it every 20 minutes, which is useful if you’re adrift and mobile. The GPS fix helps to pinpoint your location to within 100 meters. Otherwise COSPAS-SARSAT has to rely on doppler shift computations which are less accurate in determining your precise location.

There are some other features that I also like about this device: it’s waterproof to 5 meters, the built in battery has a life-span of 5 years and does not have to be manually recharged, it is guaranteed to send a signal for 24 hours once activated (at -20 centigrade) but will typically run for 40 hours, it’s easy to self-test, and difficult to activate accidentally.

Hopefully, I’ll never have to use it.

Disclosure: The author owns this product and purchased it using their own funds.


  1. I've been thinking about getting a PLB myself since I tend to do a bit of solo wandering myself. As an ex-SAR guy, I can tell you that waiting for an overdue report and visual search to find you is not the best way to go. The 406 beacons have a lot of practical field testing and are a good choice. Thanks for the review.

  2. ET and ending on the 406 MHz frequency, 2009. Search and rescue agencies had only five riders together when it crossed the national authority.

  3. I'm seriously looking into PLBs for this coming winter season, and I thank you for your timely post. For some insane reason, though, PLBs are illegal in Japan (!) – I'm trying to figure out whether the Spot (with it's independent satellite coverage) is somehow exempt. Will keep you posted.

  4. Maybe the spot is the answer – make sure to check how good their satellite coverage is in Japan and buy the extra rescue extraction insurance they offer. Do keep me posted. I am very interested in the international aspects of coverage.

  5. PLB use inland is also illegal in Britain and can result in confiscation of the unit and possibly prosecution. This is definitely something which should be changed.

  6. Diana – I am so glad that you posted your comment. PLB's are to my amazement illegal to use inland in the UK. I guess I will have to buy a SPOT afterall if I want international coverage. I will change my post in a few days to correct it. Luckily I bought the PLB at REI in the states, so I can probably return it.

  7. I really like and respect the ACR PLB's, the unit I carry most often is the FastFind 210, made by McMurdo. It's somewhat smaller than the ACR units, also has GPS, difficult to accidentally activate while still being easy when and if you need it, plus it's about HALF the Price of the ACR's (~$300 US)! I think most back-country hikers should have a PLB as 'Insurance', and since the FastFind is more Affordable while still being Reliable, it's more likely to be within the budget of more users. Working with SAR, I'd rather receive a PLB call with a specific location, than a 'Late Hiker' call with only an itinerary to go by – Too many 'Body Recovery' outcomes.

    I also use the SPOT, but only for 'Checking In' – I don't personally feel it's reliable enough to use as my 'Primary' Safety Radio, but it's certainly better than nothing!

    Plus, your 'Significant Others' may feel very 'comforted' by daily 'Check-Ins'! ;-)

    Regarding legality, if I'm in REAL Trouble, I'd rather be alive to pay the fine, than have my friends say "He always followed the rules" at my funeral, but that's just my opinion, FWIW.

    I do think that you and your readers should at least look into the "FastFind" PLB's – the '210' model with GPS, NOT the '200' which does NOT have GPS – They're the SAME Price, so I see no reason not to have the added Safety Marging that GPS provides! And, if you have the money, "FastFind" has several other models with even more advanced features.

    Just my 2 cents, Stay Safe, All of You!

    Chris T.

  8. Phil – hope to run into you on the TGO in May; we run in the same hills in the US (I'm in Portland). Interesting note re: legality – I guess my question, which mirrors Chis, is "who cares?" Not to be flip, but pushing the button and paying the fine seems trivial givent the presumed alternative. On the flip side, the fine seems a good deterrent to activating the unit for anything less than life or death situation.


  9. Jack – there is that. But here's my revised thinking. I am going to bring a SPOT after the dust settles around their lastest recall. One hidden reason is that the SPOT subscription includes foreign medical evac insurance. I don't anticipate this being an issue, but I do want to have some just in case. Like New Hampshire, the UK Mountain Rescue Teams are starting to charge for their services…..

    I saw your recent post on the TGO message board. This is going to be a blast, isn't it?

  10. I have been after a PLB for years. I do a lot of solo hiking and sometimes the trail can be a little tricky. My research however has stalled. Most noted issue with both systems is the fact that they need a clear shot at the sky. Meaning no tree canopy and no other obstacles between the device and the sky. That would in some cases be easy to solve unless you are injured and are unable to get a good shot at an open sky. That said, I do realize that if you do not check, one device allows someone to track your trip online. That could be a big benefit, at the very least someone would be able to see where you were the last time your plb had access to a clear sky.

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