SOTA SOS Monitoring

Hi Everyone:

I just gave a presentation on the Reverse Beacon Network to my local ham radio club. During Q&A, a member of our club (Rick Oliver, W3KDR) had a suggestion that I wanted to share with the group. It might be a bit controversial, but I think the idea has some merit.

Rick suggested that the SOTA software that monitors the RBN for SOTA alerts might also monitor for SOS calls. In the event that all criteria are met, the system would take action on an SOS. Here is an example of the criteria:

  1. The software would have to hear an SOS
  2. The station would have to had previously listed an Alert (as with any upcoming activation, so the system knows it’s a SOTA station).
  3. The SOTA station would have had to previously register with the system a) that it wants SOTA to take action upon hearing an SOS and b) providing contact information for whom to text upon receiving an SOS

The immediate problem with the system is the potential for false reports and pirates. That’s why the RBNGate/SOTA system might not call 911, but would instead send a text message to 2-3 emergency contact people that an SOS has been received.

This solution would somewhat parallel the work of a personal locator beacon. I’ve carried a PLB for years and have never had to use it. It’s an 8-ounce insurance policy. I’m only able to get reliable cell service on 1/3 to 1/2 of my activations, so a PLB is a nice thing to have.

Again, I fully understand the idea of using RBNGate for SOS calls will be somewhat controversial, but I wanted to share the idea with the group.


Rob, W3DX

RBNhole (and RBNgate before it) rely on the Reverse Beacon Network, which itself relies (mostly?) on CW Skimmer. I think CW Skimmer recognises CQ calls, TEST calls, and certain types of beacon calls. It does not recognise or report SOS calls. There’s therefore no way for the SOTA RBN gateway to know whether there’s an SOS call made.

Edit: A little Googling “research” seems to indicate that CW Skimmer (which is closed-source) cannot be configured to recognise SOS calls.

I am sorry but I have to say great idea but absolutely no. If you need a safety net then you need a registered EPIRB or PLB which is designed to work when you really need it. Other services such as InReach, SPOT devices or mobile phones may work but they are not in the same league as an EPIRB etc.

I can categorically state that you should not consider any of the services I help to provide as being suitable for safety of life messages.

ISTR that Jon who provides many other SOTA services has the same view as I have from when this was last discussed. I cannot speak for Andrew who is providing our RBN gateway, he can give you his opinion.

Your life is NOT in my hands.


Seems like a reasonable technical idea, but it needs the right sponsor.

I’d talk to the 14.300 folk.


I am with Andy on this. I carried my Fast Find PLB (older model than this (reasonable price on Amazon) with me in the Cheviots. In the College Valley, the really upper Harthope, or even the upper Coquet which are routes possible with some walking, but less frequent to G/SB-001 (and I have done all three), It would be easy to be lost for a day or two if something went wrong. Importantly such PLBs work in the valley where if something goes wrong it is more likely to happen on the way up. This proposal assumes that you manage to get up to a reasonable height for transmission which is its fundamental short fall. Just checked my PLB - yuk! looks like I will have to send off for a new battery - it is that old. Interestingly the person at the UK registration I contacted had a call sign when I registered and really recommended PLBs for SOTA

Technically it may be possible. Practically I’m with Andy (metaphorically). Besides the reliability issue of the software you’d be relying on to skim your call, you’ve got to:
rig your radio and aerial;
Send a morse signal.

Assuming your contacts can’t contact you direct (otherwise why bother with this method?), there is still the problem of directing the rescue services to the right location.

A PLB is a lot easier and reliable. They generally include your GPS position and then allow rescuers to home in on you (speeding up recovery). Sorry but I’ll be sticking to the PLB

For completeness’ sake, I’ll cross post what I just sent to the nasota list. That’s a nice way to shake the residual sleep from your brain in a morning: seeing a suggestion like this :slight_smile:

There is no way in hell I’d rely on RBN or RBNHOLE for a safety of life scenario. Neither are particularly reliable

Cute idea, but I would lie awake at night worried about any one relying on it, and about the lawyers descending when something didn’t go right and someone died.

I mean, the amount of legal jurisdictions that SOTA operates in now, the legal fees just ensuring we could offer such a service would be massive.

No. No. A thousand times No.

RBNHole author

I’ll add another example which was a roadhouse in outback Australia offered an “intentions book” so that people going off in certain directions could indicate when they were due back. The service was a simple one, with no obligation of assistance. Which, when two German tourists died after their car broke down and no help came, the coroner found to be wrong: simply offering the service implied an obligation to assist, and the fact the book was largely hands-off by the roadhouse owners didn’t look good, and essentially opened up civil litigation by the family of the victims.

I can see how a service like this would fall foul of those sorts of provisions in Australia, and we’re not a particularly litigious society like others where SOTA operates.

Rick’s point about not receiving SOS calls from RBN gives a good technical reason it can’t be done - although there’s a few ways you can set up safety-of-life CQ calls, but again, WHY would you rely on two pieces of fairly flaky software that have no liability insurance when you could pay for great services that offer this and can pay your estate some money if they screw up :slight_smile:

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Having been a member of Fire & Rescue service long time, I must to say the idea is good but not feasible!

The standard protocols for incoming calls is wide known in the fire, rescue, EMS and dispatchers community across Europe (even with the Brexit…).
They are based on information reliability and a number of questions is asked any time a call arrived.
With a PLB/EPIRB the protocol is clear.

Answering to a call is a team work that involves dispatchers, fire personal, ems and often helicopters, police and civil protection, at least.
The decision to send one or several agencies/vehicles is based on the amount of information, expected arrival delays and severity of the problem. Sometimes is an educated guess taken by officers with a lot of experience.
But, most important, is based on “standard” emergency calls.
That’s why the emergency calls from ships are handled by coastal stations an not by PSAPs.

So, if one look into the RBNhole and sees an SOS, what should he do: Call 112 or 911 if located in North America ? Tell them what ? What is the nature of the emergency ? How many people need assistance ? Where is the emergency ? Who am I (liability) ? etc, etc…

The number of questions that arise and liability connected with such an kind-of-alarm system is huge!

Saying so, I’m with Andy and Andrew.
PLB/EPIRB is the way to go!

Vy 73 de Pedro, CT1DBS/CU3HF

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Hi All,

If after taking all care and precautions you find yourself in danger or seriously injured and needing evacuation but don’t have a personal beacon and no mobile phone coverage then you are really in trouble. If you can rig up a station, the traditional call of SOS (mayday on phone) surely would be better than relying on a few robots.

A robotic SOS answering service is wide open to trouble makers as has already been remarked upon. If it is known there are robots about then actual people might not respond.

my 5 c worth


The emergency call system already exists as a capability in APRS. If you are OK with utilising amateur stuff for SOS calls then use APRS, no need to invent another system.

I carry a PLB (on my body) and Sat phone (in my pack). I would use the radio as the last resort.

I have however sucessfully used an HF radio, operating as a mayday relay, to call in a US Air Force Black Hawk via the Royal Flying Doctor Service that just happened to be in the area on exercise for a night time mercy mission flight to an infant who had fallen into a fire in a desert in the outback of Western Australia (about 100Km S of Fitzory Crossing for the VK’s) . So an HF radio does work.

Would things get confused if RBN heard some CW from UA9SOS, GB5SOS or VK2SOS - and some others?

I’m curious about why you put devices such as the inReach in the second league. They are most certainly sold explicitly as safety of life devices, with the added benefit of 2-way communication.

One of the reasons I chose an inReach over a simple 1-button beacon is that I get continuous confirmation that it is actually working. In general I can be confident that the battery is OK, that it knows where I am, and that it can communicate with the satellites.

In fact at one point my inReach declared itself to be unhappy with its own performance. It never stopped working entirely, but it seemed a bit reluctant to communicate with the satellites. I had it replaced under warranty. My guess is that a similar fault with a simple beacon would not have been picked up.

My main concern with the inReach is the frequency with which it gets mandatory firmware updates when I sync it. It seems hard to believe that every new firmware version is validated and tested to a standard appropriate for a safety-of-life application. I’ve never noticed any functional changes so I fear that they are in a typical cycle of exchanging one set of bugs for another. That being said, I’ve never had the firmware crash or malfunction (except for a few issues with resuming service from the “suspended” state).


Because you are not in direct contact with the emergency services who will assit you. You are going via a relay.

Yes Compton, that is exactly the difference. From an RF reliability I’d expect the PLB and Iridium units to have the same reliability of success sending a message so the difference is primarily the direct connection to emergency services vs. having an indirect connection.

I’d put Iridium based units like InReach above Spot (at more Northern / Southern lattitudes).

Is this in response to my posting? Without a quotation of the bit you’re answering it’s not entirely clear which point you are addressing.

I would have assumed that any system intended for global coverage must necessarily operate through a relay. I cannot see any practical mechanism by which an emergency beacon could directly contact the local mountain rescue team for the hill I’m on.


I have had a SPOT for many years and it works as long as you have no overhead clutter or are in a super deep/narrow canyon. The connection time is a bit slow but it works. SPOT uses LEOs but it seems to work ok.

Iridium seems superior on paper. During the large Japanese earthquake of 2011 I know of people who tried to use their Iridium phone and could not get through. Maybe they did not know how to use it. I know others who had not charged it… typical.

The new generation of Garmin devices I think will be based off the Iridium network (off the top of my head), so it should work well.

It looks like SPOT is doing a lot of upgrades in the next few weeks. Not sure what they are up to. Could the upcoming release by Garmin have something to do with it? Interesting. Competition heating up?

I’d have never thought that there was a limit to the network capacity. I hope they demanded a refund.

Not sure what the issue was (could be user errors too) but it is interesting to see how all these perform under strain.

I never thought phone carriers had a capacity issue either until that earthquake (well their allocated bandwidth is limited I guess). Networks were down for quite a few hours as everybody tried calling at the same time and overwhelmed capacity. We were lucky though, we still had electricity in Tokyo, it would have been a whole different ball game otherwise.

Things we take for granted can disappear in an instant when we do not expect it!

Off topic alert…

They certainly can. I’m a Search and Rescue volunteer in the UK. Our very basic VHF FM point to point network has saved the say a few times. There have been cases of loss of the landline, mobile and emergency services TETRA (Airwave) network, usually due to flooding. Good old VHF point to point keeps going and we can charge them it in our control van. Much like Raynet of course.

As for line capacity - it is remarkably easy to overwhelm telecommunications networks. They are generally built for 50% over expected peak. But this is way below what happens if all the local subscribers try to make a call at the same time. In the UK the mobile network is protected for emergency services use by a system called MTPAS which permits some mobile phones priority and shuts everyone else out. It’s very rarely invoked.

Which is why safety services are not consumer services.