DeLorme inReach

Andy mentioned in this month’s news that he has added support for the DeLorme inReach to his SMS spotting gateway. What he didn’t say was that he did so at my request, and I am most grateful.

Caroline and I are off tomorrow for a week in South Wales, and I will be playing with the new toy. Whilst I don’t expect mobile phone spotting to be much of a problem where we’re going, this is in part in preparation for some more isolated Scottish summits we hope to do in June.

As well as sending spot messages, which should look perfectly normal to the chasers, the device also supports the sending of regular position reports via the Iridium satellite network. My data plan allows me to send real-time position reports every 10 minutes (more detailed tracks can be uploaded via the internet retrospectively). The reports slow down to one every 4 hours when stationary. My position reports are currently public and can be seen at:

In addition, I have written a script to run on a server at work which gateways the same position reports into APRS-IS. It is all a bit Heath Robinson, but if the sealing wax and string holds together I can also be tracked as M1MAJ at or your favourite APRS client. (I won’t be changing the APRS identity for Wales).

If there’s interest, I hope to have time to write a review of the product when we get back. I hope we don’t need to press the SOS button!

Martyn M1MAJ

Which model did you go for Martyn?


I forgot! It took about 2hr to update the code and test. In fact it was harder to generate some fake spot data to inject into the system than to add the code to handle the DeLorme style messages.

Is there any possibility of supporting the SPOT 3 in a similar way? There is one customizable text message that could be sent that could contain something like W6/??-??? 14.330 ±5kHz SSB K6YOA in my case. This would be very helpful for spotting when cellular and APRS fail. 73’s Gary

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Gary, all things are feasible :wink:

The are currently 3 front ends that provide somewhere for you to send your SMS. These front end systems talk to a pair of back end systems that process the data and place the spots. The separation of message receiver and message processor adds flexibility.

There’s a UK mobile number that accepts SMS input. It’s completely virtual, there isn’t a phone/modem listening to RF. Suffice to say when someone sends an SMS to it, their mobile service provider knows what to do to get the message to this number. When a message is received it is sent to one of the back-end processors via a web request.

There’s a US number that accepts SMS input that is provided by GoogleVoice, again a virtual number. When it receives an SMS it sends the content via email to the other back end processor.

Finally there is a VK number that is a real phone. It’s an Android phone running some software written by Allen VK3HRA that forwards the SMS content via a web page access to the first back end processor.

The two back end processors are almost identical, one receives spots via email, one receives spots via a web page. The rest of the systems is identical. The could be expanded to both offer email/web input and do all sorts of fall over redundancy and other really hoopy things given enough time.

The above describes how normal SMS get processed, The first addition was my personal Iridium system. This uses an off the shelf Iridium modem. The Earth bound side uses email to communicate with the mobile unit. i.e. the mobile talks via Iridium and the fixed sends sends and receives emails. The mobile unit has a fixed ID number that looks like a 14digit phone number and that is used to identify the sender. The email back end provider is used to process this.

The DeLorme InReach uses SMS for the Earth bound side. i.e. the mobile uses Iridium but the messages are sent/received via SMS to fixed users. This means the InReach user only has to send a spot to the UK SMS server and everything else is just dandy. The problem is the SMS number that appears in the InReach messages is not fixed. You get a different number everytime you use it. DeLorme’s severs are smart enough to match which InReach unit used which SMS number. So 2 way comms is effective. If the SMS number was fixed then I would not have needed to change my software. The change was to make the system spot the message was not really from a phone but a InReach unit and to locate a unique identifier in the message.

To handle SPOT messages a few things are needed. You need to be able to embed some unique identifier in your messages so that the system knows the message is real and not spam of some kind. I need to add a SPOT message parser to the code.

So if want to send me an email via your SPOT unit to mm0fmf_sota AT I can have a look at what is sent. Make it look like the current SMS format so I can inject it straight into the existing code.
i.e. “! W6 ??? 14.430 SSB ±5kHz”

I always like to acknowledge that this spotting system is made possible by the generous donation of resources by several people in addition to myself. The US number is provided by Andrew K1YMI, the US based back-end processor runs on a server provided by Jeremy NH6Z. The VK number and handler is provided by Allen VK3HRA.

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Many thanks for the quick reply. I’ve set a custom message up on my SPOT GEN3 device and will send you an email later today when doing my planned SOTA activation. I don’t think the SPOT GEN3 is as sophisticated as the DeLorme when it comes to messaging but hopefully it does enough as it is quite a popular device in the US, although not sure how many people use it when SOTA hiking. Greatly appreciate the effort you all put into making this spotting method possible. Looking forward to hearing what you think of the message format. 73’s Gary

Andy, I sent you an e-mail yesterday with the message produced by my SPOT GEN3 in the field. I also sent one to myself, it came through:

Gary Hawkins (K6YOA)
GPS location Date/Time:05/03/2015 10:38:54 PDT
Message:W6/xx-xxx 14.335 SSB K6YOA Calling CQ CQ on this frequency plus/minus 5kHz.
Click the link below to see where I am located.
SPOT My Location | Saved by SPOT | US
If the above link does not work, try this link:
Google Maps
Gary Hawkins (K6YOA)
You have received this message because Gary Hawkins (K6YOA) has added you to their SPOT contact list.
Ready for Adventure

The SMS Message that came through to a phone looked like this:

Gary Hawk…
ll=33.57410, -116.78346
W6/xx-xxx 14.335 SSB K6YOA Calling CQ CQ on this frequency plus/minus 5kHz.

Do you think it might be possible to do something with these formats?

73’s Gary

Just to note the actual message does not contain the * at the beginning and end.

In principle this is trivial to adapt. The code already parses a variety of email formats so another one is a cut/paste/edit of an existing parser.

We need to be able to know that this message is really from your SPOT and not someone having a laugh and forging messages. I’ll talk to you off-line about that otherwise all the jokers will start sending spots on your behalf!

The only thing remaining is the message format is wrong. It’s not like an SMS spot message so it isn’t going to work. It has to look like the format I gave earlier. But that’s a mere detail.

I’d be interested to know what airtime plans are available.

I’ve been seriously thinking of going down the Spot route for sometime, but this is another option worth looking at.

SPOT coverage was “spotty” in these Northern Latitudes Pete. Much better if you were always south of 50degs North.

+1 for that, Anything Iridium based will beat the Globalstar SPOT system at UK latitudes.

The other main outdoor Iridium based tracker is made by a UK company - Yellowbrick.

I am not connected to this company or endorse its products.

I’m personally not that bothered about tracking, I just want a “life threatening emergency” only device. So I carry a Personal Locator Beacon which communicates through the intergovernmental managed COSPAS/SARSAT service. Five year storage battery life and no subscription. BUT… as I say, no tracking, messaging or anything other than “I’m in big trouble and I am at this location”.

I was in the south of the “GW/NW” area over the weekend and spent almost all of it without any mobile coverage (including emergency roaming) in rough country that not many folk travel. A simple twisted ankle could have been serious and it would have been a while before anyone found me. If I was partially mobile my best bet would have been to set up my amatuer radio kit, but you can’t rely on that.

Thanks Gerald and Andy.
Yes I knew about the SPOT limitations in the high latitudes.
I suppose I was driven to it because it’s a mandatory requirement for participating in the Everglades Challenge which I have designs on participating in …

The other two Iridium options look very interesting. I’m still not clear on how the airtime packages work, I’ll have to do a bit more studying.
Whilst a PLB is great for real life threatening issues, I can see real advantage in being able to make contact with the outside world in less serious situations.
These devices fit in nicely with my other outdoor activities.


Airtime access for my Iridium unit is £8+vat / month. You don’t need to continue the access, so you can turn on access for a month then leave it for a few months before renewing. Messages cost is based on length and 50chars (1 Unit) costs £0.12+vat for messages sent or received. In addition if you poll the network to see if you have a message it costs 1 unit. Maximum message size is 320chars.

Under open skies, such as a summit you have perfect access and from hitting send till the message being in the system takes about 20secs (10 secs to confirm network access and signal condition and 10 secs to obtain a message slot and send). The power comes from a USB connection that can only provide limited current so there is a 3F supercap to provide the current, this has to charge up and limits you to 1 message every 30secs. But you would soon go broke if you hammered the link! There is also a rate limit access arrangement that network applies so you cannot hog the satellite, if you try to send too many messages too quickly you don’t get allocated a slot for a few minutes to throttle the data.

After looking over Spot and the Delorme InReach I picked the InReach for the two way messaging and message confirmation (that it was indeed received by the satellite). I have the older little black InReach unit with no screen and three preset messages that can be sent from a single button (messages can be changed/personalized on the website). This model works great for my outdoor activities, but the Spot and Delorme websites detail their device and plan details better than I can.

To save bandwidth, please see my review of the InReach at It’s 5 stars and author name is “Mike”. Describes my experience with the unit, but please bear in mind it follows my specific use/experience. Your needs may differ. It’s worked great for what I wanted, and no financial connections, etc.

I hope to use the InReach to announce an activation in a couple of weeks while home in East KY. Not a lot of cell coverage, so the InReach will have to pass when QRV. The summit is W4K/EC-020, and hope to get on at least 20, 17, and 10m. Planning both CW and SSB to give most possible a chance. Of course this depends on family, weather, planets aligning properly, and hiking partner (14 yr old daughter) not getting too bored too quick. I understand that thanks to Andy’s hard work we can now send an email QRV spot from the InReach to the spot page, so may have to go this route due to the spotty cell coverage.


Mike, N4VBV

The DeLorme web site is reasonably clear about the options available direct from them: basically 4 levels of access plus the “Freedom” option which gives you more flexibility (at a cost). These plans are available in the USA and EU. There are alternative plans from the UK distributor which charge on a different basis (byte count rather than specific message types).

I’ll try to write up a bit more on this when I get back from holiday.


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Gerald, I would be interested to know more details about the PLB you use.

73 Angel

Mike, can you advise the date of your Amazon review and whether you did it on the Explorer or SE model? I would like to read it, but can’t find it amongst all the reviews…

OK, this is a bit off topic as it’s about PLBs and not DeLorme…

Mine is the slightly older brother of this one. Very compact and light.

There are several competing products in this class. I test mine monthly, (with the test button - not by setting it off!) but I’ve never needed it for… (I’ll trail that sentence off to try not to tempt fate too much)

The following assumes you are British… other countries have similar registration systems.

Basically, you receive it, fill out the registration online on the UK Maritime and Coastguard Agency website (for free) and they send you a sticker to put on the outside with the registration details. There’s no legal requirement to register, but it’s STRONGLY recommended as you give the MCA two emergency contacts. If the beacon is activated they try contacting them to try to verify if is a genuine alert. If there is any doubt then they treat it as genuine.

COSPAS/SARSAT is one of those quiet international success stories. Founded by USSR, France, US and Canada in the middle of the Cold War in 1979 it has gone on to be adopted around the world, with tens of thousands of people rescued. The latest upgrade with transponders on Medium Earth Orbit Satellites (known as MEOSAR) will further enhance the service and make it almost certain your distress signal is picked up in seconds, provided you are not under really deep tree cover or in a very deep narrow canyon.