I've been carrying GME Personal Locator Beacons for over a decade. The first was the MT410G — that must be 12 or 13 years old now. Then the MT610G, which I've had in every vehicle since. Fortunately I've never had to activate either in a real emergency. But that's exactly the point. The peace of mind from knowing a working PLB is in the glovebox, with a seven-year battery and no subscription required, is worth its weight in gold when you're solo in remote country.
GME recently sent me the new MT620GR to test. On the outside it looks nearly identical to the MT610G. The real difference is something called Return Link Service, or RLS — and once you understand what it does, you understand why it matters.
What Return Link Service Actually Does
Without RLS — which is how every PLB before this one worked — you activate the beacon and you wait. You have no idea whether your distress signal has reached a satellite. In open flat terrain with a clear sky, it almost certainly has. But in a deep gorge, heavy tree cover, a steep-sided gully, or anywhere your view of the sky is compromised, you don't know. You press the button and hope.
With RLS, you activate the MT620GR and within 10 to 20 minutes a blue LED flashes. That flash confirms that your distress alert has been received by a Rescue Coordination Centre — in Australia, that's AMSA — and that help is on the way.
Here's how the chain actually works. When you activate the MT620GR, it transmits your distress alert using the RLS protocol on 406 MHz. That alert is picked up by MEOSAR satellites, processed by the Cospas-Sarsat system, and routed to AMSA. AMSA then requests a Return Link Message through the Galileo Return Link Service Provider based in Toulouse. That message is broadcast back to your beacon via the Galileo satellite network, which triggers the blue LED.
The key thing to understand — and I confirmed this directly with GME — is that RLS is a Galileo-only feature. Galileo is currently the only GNSS constellation capable of sending that return confirmation back to the beacon. GPS, GLONASS, and BeiDou don't support it, and there are no current plans to change that.
That has one important practical implication: if the blue LED doesn't flash, it does not necessarily mean your distress signal failed. The core 406 MHz alert can still be successfully received and acted on by the responsible RCC through the standard Cospas-Sarsat system — exactly as it was before RLS existed. What the absence of confirmation tells you is that the specific Galileo return path didn't complete, which could be terrain, satellite geometry, or any number of factors.
So what do you do if the blue LED doesn't appear? The same thing you'd do with any PLB if you had doubt about your situation — move to a more exposed position with better sky view if you're physically able to. Get clear of tree cover, gorge walls, steep terrain. Activate again from a better position. But don't assume you're not being searched for, because the primary alert may well have gone through.
Research has shown that survival rates increase substantially when people know help is coming. The RLS confirmation is that knowledge. When the blue light flashes, stay put, stay calm, conserve energy. That certainty is worth having, particularly for solo travellers in difficult terrain — even accounting for the nuance above.
The MT620GR vs the MT610G — What Changed
The physical format is essentially identical. Same weight (160g), same dimensions (88 × 66 × 37mm, one millimetre deeper than the MT610G), same IP68 waterproofing (10 metres of saltwater for one hour), same inherently buoyant design, same 7-year battery, same 6-year warranty, same 2-step activation, same 121.5 MHz homing signal, same Australian design and manufacture from GME's Sydney facility.
What's new:
- Return Link Service (RLS) — the blue LED confirmation. The defining upgrade.
- NFC connectivity — tap the beacon to your phone to connect to the Accusat Connect app.
- GME Accusat Connect app — iOS and Android. Battery status check, comprehensive self-tests, and a log of every test run on your specific beacon. Particularly useful for checking the battery is healthy before a remote trip.
- Audible buzzer on activation — the MT620GR confirms activation with a buzzer as well as the visual LED strobe. You hear it activating without needing to look at the unit.
- Upgraded GNSS receiver — dual constellation GPS L1C/A and Galileo E1B/C. Cold start 30 seconds, hot start 1 second.
What hasn't changed is equally important: no subscription, no annual fee, no message count to manage. The MT620GR is a one-time purchase. You register it with AMSA (free, required by law, takes 10 minutes at beacons.amsa.gov.au), store it in the vehicle, and it's ready for up to seven years.
The No-Subscription Argument
This is where PLBs make economic sense compared to satellite messengers like the Garmin inReach Mini 2 or Zoleo.
Both the Garmin and the Zoleo require ongoing subscriptions to function — typically $15 to $35 per month depending on your plan and usage. Over three years, that's $540 to $1,260 in subscription costs alone, on top of the device purchase price.
The MT620GR costs AU$569 upfront. Nothing after that for seven years. The MT610G still retails from around $379 to $429, if cost is the primary consideration.
For pure emergency SOS use — which is the one scenario where you actually need this device — the PLB wins on cost, reliability, and signal routing. Your SOS goes directly to RCC Australia (Rescue Coordination Centre Australia), the Australian authority. Two-way messenger SOS signals go to an overseas IERCC and then get routed to local authorities — an extra step and potential delay. The PLB also transmits continuously for at least 24 hours, far longer than any satellite messenger battery will last on SOS. And it emits a 121.5 MHz homing signal that SAR aircraft use to narrow down your position once they're in the area. No satellite messenger does this.
What I Actually Carry — and When
The GME MT620GR is what I always carry. It lives in the glovebox of every vehicle I take remote. That hasn't changed since I first started carrying the MT410G over a decade ago.
I also carry the Garmin inReach Mini 2, particularly for hiking and when I'm away from the car for extended periods. The inReach is a two-way messenger — it lets me stay in contact with my family, share my track, and use the navigation features. For dedicated off-road navigation I use Memory-Map with the HEMA map pack — full breakdown in my best off-road navigation app guide. It serves a different purpose to the PLB. They're not substitutes for each other.
With all the subscription costs factored in over time, the GME PLB is unquestionably the better option if you're looking for pure emergency capability. If you also want to message your family while you're out there, you'll need a messenger on top of it. That's just the reality of what each device is designed to do.
Should You Upgrade from the MT610G?
If your MT610G is in date, working correctly, and you've been testing it regularly — there's no urgent reason to replace it. The MT610G has a proven track record.
If you're in the market for a new beacon, buy the MT620GR. The price premium over the MT610G is approximately $140 to $210 depending on where you shop, and the RLS feature is genuinely useful — especially if you do solo hiking or spend time in terrain with limited sky view.
If you do a lot of solo remote travel, bushwalking in gorge country, or anything where satellite line-of-sight is not guaranteed, the upgrade case is strong.
Register Before You Go Out Bush
If you're new to PLBs, this is the step that most people overlook — and it's the most important one. Before you take the MT620GR anywhere remote, you must register it with the Australian Maritime Safety Authority. Registration is free, takes about 10 minutes, and is required by law. You do it at beacons.amsa.gov.au.
Registration links your beacon's unique 15-digit hex ID — encoded in every 406 MHz distress transmission — to your name, your emergency contacts, and your vehicle details. If your beacon activates, AMSA uses that information to confirm your identity, contact your next of kin to rule out accidental activation, and brief SAR teams on what to look for. An unregistered beacon will still trigger a rescue response, but it costs time and resources that could be spent finding you faster. Re-registration is required every two years and is also free. Do it before your first trip. Don't leave it until you're already on the road.
A Real Rescue Story
The stakes of getting emergency communication right are real. I covered a real helicopter rescue at Wounded Knee Canyon — triggered by a Garmin inReach Mini 2 — and walked through what I learned about the differences between PLBs and two-way messengers in practice:
The Full PLB Deep-Dive
If you want the full explanation of how PLBs work, the difference between PLBs and EPIRBs, how to register, how to test, and why I don't consider a satellite messenger a PLB replacement:
If you're planning something serious — the Simpson Desert, a Kimberley traverse, anything genuinely remote — your emergency communication stack deserves as much thought as your recovery gear. My Simpson Desert planning guide covers what I carry and why, and the book goes into the full picture including communication protocols, emergency procedures, and what to do before you leave the bitumen.
The MT620GR is the PLB I'd buy today if I were starting from scratch. The Return Link Service changes the activation experience from "press and hope" to "press and know" — which matters most when you need it. More gear reviews and field tests are on the AllOffRoad YouTube channel.
