How I Use My Garmin inReach Mini Satellite Communicator

A few years ago, I wrote a post about how I got started adventuring out into the middle of nowhere all by myself. I went into a bunch of details about my experiences growing up, and how those experiences shaped me into the traveler I've become. Still, one of the things I mentioned not being fully prepared for was a bodily injury or "now-we're stranded" problem with the Tacoma.

It was about six months ago that I acquired a Garmin inReach Mini. I wrote about it only briefly as part of the Hiking Saline Valley trip that spurred the purchase - I was going to be doing some remote hiking, as well as the Rig Review following the trip.

For a few of the hikes on the trip, I had more safety gear than normal.

Having only mentioned that I bought it - and never really went into detail on how I use it - I realize that getting a satellite communicator is the easy part of the equation. Using it efficiently - both from a cost and communication perspective - is actually the more important part to "get right." So, here's how to make the most of a Garmin inReach Mini satellite communicator.

Also - most importantly - I owe much thanks to Ken @DVExile for sharing his thoughts on various satellite communicators and their use. I've modeled much of my solution - and the information here - on his knowledge and extremely pragmatic mindset.

Lastly, in today's world of instafluencers and sponsor-supported youtubers, it's worth mentioning that I am not sponsored by Garmin or any other vendor mentioned here. Like every other bit of gear I have, I spent my money on what I hoped would be the best for my situation.

My Subscription Rant

I dislike subscriptions. I know everything is going that direction, but I've refrained - to the extent possible - from the plethora of streaming music and video services. Of course, my utilities, internet, and cell phone are all subscriptions, but I'm careful to monitor their costs to make sure I'm not paying for more than I actually use.

In fact, my aversion to subscriptions has been the primary motivator behind my reluctance to pick up an inReach Mini, and even though I know an inReach would be better, I've seriously considered a Personal Locator Beacon (PLB) device instead. For more on why I didn't go that route, see Why a Garmin inReach and not a SPOT or dedicated PLB?

The Goal

So, my rant should make it clear that biggest hurdle for me with the inReach Mini was the subscription. As such, my goal was to minimize the cost while maximizing the benefits. And there were two benefits/goals I was hoping to achieve:

1. The ability to trigger a Search and Rescue (SAR) via SOS functionality, without cell service.
2. The ability to communicate my status and location to loved ones back home on a regular basis, even without cell service.

Garmin has three consumer plans - ranging from $11.95 to $64.95 - with which I could attempt to meet these goals:

	SAFETY	RECREATION	EXPEDITION
SOS	Unlimited	Unlimited	Unlimited
Text messages (*160 characters)	10	40	Unlimited
Preset messages (up to 3)	Unlimited	Unlimited	Unlimited
Tracking intervals	10 min+	10 min+	2 min+
Send/track points	$0.10 ea	Unlimited	Unlimited
Location requests	$0.10 ea	Unlimited	Unlimited
Basic weather	1 text message ea	1 text message ea	Unlimited
Premium weather	$1.00 ea	$1.00 ea	$1.00 ea
Premium marine weather	$1.00 ea	$1.00 ea	$1.00 ea
	MONTHLY CHARGES
Annual plans	$11.95/mo	$24.95/mo	$49.95/mo
Freedom plans	$14.95/mo	$34.95/mo	$64.95/mo
	OVERAGE CHARGES
Each message (*160 characters)	$0.50	$0.50	N/A

Garmin inReach subscription pricing, as of June 2022. (source)

The Solution

All three of these plans include a solution to my first goal - sending an SOS to spin up SAR, so my focus was on the second - communicating my status and location on a regular basis.

The most expensive plan would clearly solve the issue - I'd have an unlimited number of text messages that I could send, and I could also communicate an unlimited number of tracking points - up to one every two minutes - so they'd know where I was. The other two plans varied only in the number of text messages, and neither 10 nor 40 seemed like they would approach my desire for "regular basis."

However, while arbitrary Text messages can quickly get expensive, all plans allow me to send Preset messages - of which I can define up to three (and each one can be delivered to any number of email/SMS recipients) - an unlimited number of times. Preset messages also include the location from which they are sent, so I set about devising three messages that would meet my goal around regular status messages.

So what are the messages, and when might I send them?

Message 1: I am with my vehicle or in camp and OK, notify SAR if you don't hear from me in 36 hours.

This is a message that I send many times each day, and always send when I reach camp at night. Basically, it resets a 36-hour window during which SAR will not be called. The assumption when I send this message is that I am healthy and self-sufficient for an extended period of time - with food, shelter, etc.

Message 2: I am hiking and OK, notify SAR if you don't hear from me by the later of [a] 9pm (my time), [b] two hours after sunset (my time), [c] two hours from now.

This is a message that I send when leaving the truck. Generally, for me this is hiking, but it can be for any number of reasons, and it shortens the window before which SAR will be called.

Message 3: I am hiking and OK but doing something tricky, notify SAR if you don't hear from me within 1 hour.

This message is pretty self-explanatory - it lets folks know that something risky is going on and shortens the SAR window dramatically. The idea is that the risky activity takes only a few minutes, and then Message 2 or Message 1 are sent again (often multiple times in order to ensure delivery) as normal activities are resumed.

I've configured each of these preset messages to send to several individuals - via both email and SMS - who I think can help should SAR need to be called. Further - and just as importantly - I've educated them on when and why I would send each message, and instructed them to not respond, since responses count against my text message count for the month.

If fact, since getting the inReach, I've only sent one custom text message out of my monthly allotment. It was a doozy, when we broke a main rear leaf spring deep in the Death Valley outback.

Being able to send a message - even in a situation that wasn't life-or-death - was comforting in itself.

And with that, I have a solution that works with the lowest-cost plan, which I've subscribed to at the "annual" level of $12/month, or a little over $150/year after taxes.

 

Background and Frequently Asked Questions

Given my solution above, I will try to anticipate a few questions, but please don't hesitate to ask more, and I'll add them (plus answers) to the list. Note that a large portion of this content is courtesy of Ken.

What are the differences between SPOT, inReach, and dedicated PLBs?

SPOT, InReach and PLBs all use LEO (low earth orbit) constellations. This means that having an unobstructed view of a particular part of the sky is not critical since the satellites are constantly moving overhead. At some point the device will eventually have view of a satellite, even in fairly restricted locations like deep canyons. Further, when in emergency mode, all of the beacons transmit continuously. This means that given enough time (and battery) they will get a message out, since eventually a passing satellite will have view of the transmitter.

The specifics for each are a bit different.

SPOT

Is a commercial service with a subscription. SPOT uses the GlobalStar constellation and more specifically uses a blind one-way transmission for sending messages. Location information for those messages is acquired using standard GPS.

The SPOT beacon (that is their lower cost actual beacon products, not some of their two way messengers) - when used for routine messages - just blindly sends the message three times over 15 minutes hoping that your sky view and a satellite line up for one of those three tries. If you've got open skies it probably succeeds on the first try; with restricted skies, odds decline with the reduction of sky.

As noted for all the products, when in emergency mode, the beacon transmits continuously and thus the odds of a message getting through are much, much higher than in routine messaging. Still, even in emergency mode, there is a good chance the SPOT beacon might not be able to get a GPS fix if there isn't much sky available, and thus your emergency message won't have location information. Still, it will start a SAR effort and the SAR folks can use whatever resources they have (loved ones, your itinerary, an earlier message you sent with a GPS fix) to narrow the search. For this reason, when using SPOT, it is best to send periodic status messages when you know you have good sky view so that SAR will have a recent fix if you have an emergency with restricted sky view.

inReach

Is a commercial service with a subscription. InReach uses Iridium which supports two-way transmission with acknowledgement for communication. It also uses GPS to determine location.

The key difference is that Iridium inReach devices listen for a signal from an Iridium satellite before even attempting to send a message. If it can't hear the satellite, then the satellite certainly can't hear it either. This allows it to be much "smarter" than a SPOT beacon, since the SPOT blindly transmits and "hopes" a satellite is listening. InReach, instead, listens for the satellite (a much, much lower power operation than continuously transmitting in the blind) and when one is heard, the inReach does a quick handshake before sending out the message and receiving a read receipt from the satellite.

By default, many InReach devices take power saving one step further and won't even try to listen for Iridium until it can hear GPS first. In this mode, they will refuse to send a message without GPS unless you intervene. Combined with the fact that some InReach devices (e.g. Mini) have really sucky GPS front ends, this can make the network seem far less reliable than it actually is. Intervening to force transmission without location is not difficult, but the UI should do a better job of informing the user about what is going on.

In emergency mode all these GPS restrictions are removed, and the communications are more robust. Even with restricted sky you just need to wait long enough for an Iridium satellite to pass overhead, at which point it is highly likely an emergency message will get out. Like SPOT, it may not have a GPS coordinate in the message, but again SAR can work around that.

PLB (Personal Locator Beacon)

Is a public service with no subscription. A PLB when activated begins transmitting continuously to the SARSAT constellation at a power about 5 to 10 times higher than the Iridium or GlobalStar based systems.*

PLBs don't support routine messages at all. It is an emergency use device only - the very act of turning it on means you need immediate help. It is similar to the beacons used in aircraft and ships that automatically activate when they crash or sink.

Most PLBs have an integrated GPS and send location in their message. However, even without GPS the SARSAT constellation itself uses a synthetic aperture technique to geolocate the PLB transmission - usually accurate to within a few miles. SAR teams also have radio direction finding equipment to home in on the PLB beacon.

For more information on the PLB system, this article does a good job of explaining in more detail.

* Higher power transmission does not necessarily equate to more reliability. See I've heard/read that a PLB is more reliable. Is that true?.

Why a Garmin inReach and not a SPOT or dedicated PLB?

This is a great question, and there's no single correct answer - or at least, no single answer that is correct for all users/situations. First, it's important to break down the different device classes, of which there are essentially two:

1. PLB - Personal Locator Beacon - Does not require subscription, device costs about $250, battery is good for 5 to 6 years depending on the model (battery replacement service is around $100). Amortized cost over a 10 year period would thus be about $35 per year. This does one thing, it calls SAR and they respond assuming a life threatening emergency (usually after quickly contacting a list of emergency contacts to try and verify it isn't a false alarm, but the assumption when a PLB activation is detected is that someone needs rapid extraction from a life threatening situation). The only thing you need to do, which is free, is register your beacon with the SAR network so they have emergency contact information for you. Satellite constellation is government funded and operated. Extremely reliable, you push that button you pretty much are going to get rescued no matter what. This is essentially the same system that life-rafts for commercial aircraft, ships and oil rigs use. It does one thing only and does it really well.
2. SEND systems like SPOT, inReach - Does require a subscription, device cost varies from $150-$500+, batteries are rechargeable via USB. These are messaging platforms that include a SOS component to them, essentially like text messaging on a satellite phone. Satellites are commercially owned and operated (hence they need to make money from you on a subscription). Some are one way only (SPOT) and others offer two way communication (inReach). They have a reputation (perhaps unfounded) of being less reliable for SOS than a PLB.

Then, comparing SEND systems, the two primary are inReach and SPOT:

• Price: While the inReach Mini is a more expensive device (~$400 vs ~$150), its annual subscription cost is about the same as SPOT, and over time the subscription cost is the larger of the two costs, bring the prices inline with each other. Advantage: neither.
• Satellite Constellation: SPOT uses GlobalStar, inReach uses Iridium. Both are Low Earth Orbit (LEO) constellations which means having view of a particular part of the sky is not critical. The satellites are constantly moving overhead and at some point the device will eventually have view of a satellite even in fairly restricted locations like deep canyons. Advantage: neither.
• Messaging: SPOT devices are one-way-only when sending messages, so there is no acknowledgement that a message was sent. Therefore it is wise/necessary to send the same message repeatedly to increase the likelihood of it reaching the intended recipients. inReach allows for two-way messaging, and delivery confirmation, giving it a fairly obvious advantage over SPOT as far as coordinating with people - either in an emergency or just when checking in. Advantage: inReach.
• Location Data: Both SPOT and InReach depend on a GPS fix to give rescuers your location. That should rarely be a problem, but might be an issue in the classic "pinned in a slot canyon" situation. With InReach you could of course describe your location via the message though you might have poor Iridium connectivity in the same slot canyon. Advantage: neither.

Thus, while the initial price of a SPOT is less, over time the advantage tilts to inReach due to the two-way messaging.

Then, to compare the inReach (the prefered Send device) to a PLB:

• Price: An actual PLB (like the ACR ResQLink) is priced around $270 and requires no monthly fee or plan. It is surely a less expensive option as compared to an inReach. Advantage: PLB.
• Satellite Constellation: PLB uses SARSAT, which like Iridium is a LEO constellation with similar characteristics. Advantage: neither.
• Messaging: A PLB can only be used in an emergency and has no messaging features at all. Advantage: inReach.
• Location: If a PLB has a GPS fix it will send it in its message giving rescuers an exact location. However, even without a GPS fix the system is designed to give a good location using just the raw beacon signal. This will get rescuers to within a few miles of you at which point they can home in on the beacon signal itself using handheld equipment. As such, it may get you out of more "slot-canyon" style situations than an inReach. Advantage: PLB.

It may seem then that a PLB would be better than an inReach - and for some it may be. However, the two-way messaging of the inReach is extremely valuable when using the device as both a SAR device and a way to regularly communicate status to loved ones back home when no cell signal is available. Further, the ability to transmit a signal on the Iridium system might be more robust than the SARSAT system, though location and specific conditions are likely to play a larger role than the theoretical robustness (see I've heard/read that a PLB is more reliable. Is that true?).

So, there is no "perfect" solution but any of the above is of course much better than hoping to have cell signal when something goes wrong!

Should I get a device that does both SOS as well as navigation/mapping?

In my opinion, no. A phone or tablet will be orders of magnitude better at mapping and route tracking these days, with fantastic screens and user interfaces that are honed by app developers for ease of use. Additionally, the last thing I want to do is suck all of the battery life out of my SOS device while using it for navigation, only to have the battery die when I need it to call Search and Rescue. For that reason, I like to keep the devices separate, and I turn on the SOS device - with a full battery - when I need to send a message.

I've heard/read that a PLB is more reliable. Is that true?

If one does any amount of reading on the internet about PLBs and satellite messengers, they are bound to come across articles that proclaim the superiority of a PLBs reliability over a messenger such as the SPOT or inReach, due to the higher transmission power of a PLB. (see [1] [2])

However, a fantastic Link Budget Analysis by Ken recently flips that assumption on its head. He explains it better than I do, so I'll simply quote his entire analysis here.

TL;DR - despite PLBs having the online reputation of likely to be more reliable in an emergency that actually for the case of trapped in a canyon or other terrain with limited view of the sky Iridium based beacons like InReach are probably more likely to successfully connect sooner.

At present I consider either a PLB or InReach to be the best options for emergency satellite based communications so I'm leaving SPOT out of the mix though it is quite functional as well. PLBs are a one way device that can only be used in a true emergency and require no subscription. InReach is a two-way device that can be used for routine communications as well as in emergencies and requires a subscription.

A constant question has been:

In an honest to goodness emergency would the LEOSAR, MEOSAR and GEOSAR based PLB or the Iridium based InReach be more robust?

The general consensus online has always seemed to be that the PLB should be more robust based on the fact that it emits 5W as opposed to InReach devices which emit 1.6W. But of course that's only one part of the communications link, there is the whole question of the capability of the satellite that receives the transmission as well as the efficiency of the modulation and coding used for the transmission.

All of these options will work great and quickly with clear sky view. In the marine environment this is pretty much always guaranteed. There is no need to do any analysis for this as both systems have plenty of margin in such a situation.

For a hiker though the question is often which will work best with a severely restricted sky such as in a deep canyon. In this scenario there are two possible means for a message to get out.

First, you could get a lucky pass of a satellite that passes through your tiny window of sky. For this case what matters is how likely is that to happen with the particular satellite constellation. In this case Iridium is the clear winner with a constellation of 66 operational satellites compared to just six LEOSAR payloads (MEOSAR and GEOSAR are less favorable in this condition and so aren't considered). You are effectively about ten times as likely to end up with a favorable Iridium pass.

Second, your transmission could reflect or scatter off the canyon wall to find a path that isn't a direct line of sight. In this case the reflected signal will be significantly attenuated so the question is just how much margin there is in the link such that you might still get a message out despite the attenuation.

In satellite link analysis we always have what is called a "link budget" which is an accounting of all the gains and losses in the system for a given scenario which computes the amount of signal to noise available at the demodulator and compares that to the minimum signal to noise required to successfully demodulate the message. When folks say the PLB is better because it emits 5W instead of 1.6W that is only looking at one entry in the link budget. It is as if we evaluated businesses only based on their revenues and ignored their expenses (though admittedly that is a popular thing to do these days).

Typically a link budget is computed for the "worst case" for a system to ensure the system will still work in that "worst case". Often there is a lot of margin (i.e. far more signal power available than needed) in more typical situations. And the "worst case" can be very different for different systems because what the "worst case" is really depends on how you intend to use the system.

Neither Iridium nor LEOSAR consider transmission in a canyon to be their "worst case", rather they write it off as an irrelevant case. Instead they model their worst case as direct line of sight to a satellite being low on the horizon since that gives the longest path distance. But for our trapped hiker what really matters is when a satellite is nearly overhead (typically a best case) how much extra signal power is there such that we might close the link with reflection off of terrain rather than direct line of sight? We will need to compute our own link budget for this situation.

With much digging I've found adequate references to do a simple link budget for a satellite directly overhead with direct line of sight:

LEOSAR

• PLB EIRP: 7.0 dBWi
• Free Space Loss: 142.6 dB
• Polarization Loss: 4 dB
• Fading Loss: 2.5 dB
• LEOSAR G/T: -32 dB/K
• Boltzmann's Constant: -228.6 dBJ/K

Computed C/No: 54.5 dBHz
Required C/No: 36 dBHz
Margin: 18.5 dB

Iridium NEXT

• InReach EIRP: 2.0 dBWi
• Free Space Loss: 154.4 dB
• Polarization Loss: 4 dB
• Fading Loss: 2.5 dB
• Iridium central spot beam G/T: -8 dB/K
• Boltzmann's Constant: -228.6 dBJ/K

Computed C/No: 61.7 dBHz
Required C/No: 42 dBHz
Margin: 19.7 dB

Conclusion

Likely the above is Greek to almost any reader here. The key numbers above are the margins, this is the amount of attenuation the links can tolerate and still close. Note that Iridium's is slightly higher than LEOSAR despite the PLB emitting more power than InReach. If you aren't familiar with a dB scale the 1.2 dB difference there is a factor of 1.3 and is well within the likely uncertainties of these numbers. So the systems have essentially the same performance with a satellite directly overhead and the same amount of margin to give up to attenuation for a reflected path rather than direct line of sight.

So despite the fact the PLB emits more power actually the InReach is slightly more likely to connect without line of sight. The reason is in that G/T number which is a figure of merit for a receiving platform. LEOSAR is just a small payload that is hosted on things like weather satellites and it therefore has only a small low gain antenna. Iridium is a purpose built communications satellite with all its mass and volume dedicated to communications and thus has effectively a very high gain antenna (actually it is a phased array antenna with multiple spot beams but same difference).

Another important factor here is that both systems have quite a bit of margin when the satellite is nearly directly overhead. That means there is in fact a chance that you might connect without line of sight. The Iridium margin of nearly 20 dB means that even with reflection only providing 1% of the power of a line of sight path the link would still close. That's a potential amount of attenuation on a glancing path off of a canyon wall. If the margins were only say 3 or 5 dB then we'd say it was very unlikely reflection would ever be good enough to close. But at 15 to 20 dB there is probably a reasonable chance a canyon wall would be a good enough reflector to close the link.

Add to this the fact that there are far more Iridium satellites than LEOSAR satellites such that you are more likely to end up with a favorable geometry and it appears pretty clear that Iridium is rather more likely to get a message and get it sooner than LEOSAR in a restricted sky environment.

Some details for the curious...

I felt it would be a bit over the top to explain link budgets in this post, but feel free to ask any questions and I'll try to answer them best I can. For anyone in the future who does understand link budgets that might stumble upon this in the future I'll provide some source details.

For both systems I assume the beacon antenna linear polarized (PLBs are in fact while I'm assuming that InReach is as well since their antennas seem too small compared to the wavelength to produce an efficient circularly polarized design) and both systems have circularly polarized antennas on the satellites. This is fairly common for mobile satellite designs and is reflected in the 4 dB polarization loss in the link budget (this 4 dB actually in the Copas-Sarsat documentation).

The LEOSAR numbers mostly come the publicly available Copas-Sarsat documentation specifically C/S T.014 Annex H where a link budget for an elevation of 5 degrees is given. I've modified the G/T to account for slightly lower performance directly below the satellite based on antenna patterns shown in C/S T.003. I've set the required C/No based on an Eb/No of 9 dB which may be a bit favorable for the SARP-3 processor. There seemed to be inconsistencies in the documentation for SARP-3 performance (namely it references a 300K system temperature when in fact the system temperature is actually 1000K and the numbers in the documents make more sense if we use 1000K). The SARR "bent pipe" path is theoretically a bit disadvantaged compared to the on board SARP processor so I assumed SARP processing.

The Iridium numbers assume the same polarization and fading loss as the LEOSAR case though likely the fading is slightly lower at 1600 MHz compared to 406 MHz, so slightly disadvantaging Iridium in the comparison. The G/T comes from a FCC 312 Schedule S submitted for the Iridium NEXT constellation, specifically in this case one of the central beams which have a lower G/T than the edge beams. The C/No is based on an Eb/No of 8 dB which is based on a theoretical Eb/No of about 7 dB for BER of 1e-5 for the BCH(31,20) FEC used in SBD messages.

In summary I've made slightly favorable assumptions for PLB/LEOSAR and slightly unfavorable assumptions for InReach/Iridium and in the end InReach/Iridium still came out on top by a bit.

Now, one unaccounted for difference here is that the PLB transmits blindly once every 50 seconds while InReach needs to acquire the satellite downlink before attempting to transmit. If the InReach never acquires the satellite downlink it will never attempt to transmit as far as I can tell. I am assuming that the reflected channel is nearly symmetric so if the path to transmit exists the InReach will also acquire the downlink. Additionally the 9603 modem documentation (used in InReach devices) implies the downlink margin is about 6 dB higher than the uplink so this is probably a reasonable assumption.

Should I use a satellite communicator (PLB, inReach, SPOT, etc.) or a cell booster like a WeBoost or a WiFi router?

These two devices are for entirely different things. If you're looking for a safety device, then a WiFi router, or even a cell booster aren't what you're looking for. You need something that's satellite based and can communicate when there's no WiFi or cell signal available.

On the other hand, a satellite communicator will never be the right call for transmitting large amounts of data, phone calls, or thousands of text messages. While a cell booster can't create cellular service where there isn't any, it can boost weak, unreliable service quite efficiently, making it the right choice for "broadband-style" connectivity in more remote areas.

Note: While not broadly available, Starlink may become a product that provides the best of both worlds, though in a larger form factor than a PLB-style device. Additionally, the subscription cost for the service is significantly more expensive than other solutions.