Until the recent Ofcom changes to the UK amateur radio license, unless one applied for a NoV, it was not legal to leave a radio unattended. For clarity this meant transmit unattended in the amateur bands. Since the license updates, provided the power level is below a certain limit, then unattended operation is now permitted.
My wife works at a school for children who have special needs, including autism, ADHD, selective mutism and mental health issues. She been asked to start up the schoolās first Duke Of Edinburgh award scheme, but the issue with doing this in such a specialist school is that safe guarding is key. The children are notorious for going astray, and so keeping track of them when they venture out into the Peak District on their DoE expeditions is paramount.
As some of you may know, Iāve being playing around with LoRa and APES recently; and with the help of Richard G3CWI, there a number of unattended LoRa iGates and digirepeaters - all of which receive and transmit - dotted around the Peak District and Cheshire. I was therefore wondering if under the new licensing rules, as a licenced radio amateur ,whether I could use LoRa and APRS to track the childrenās location during their expeditions ? For example, could I create a number of trackers - give each my callsign but with a different suffix (e.g. M0JKS-1ā¦M0JKS-10) and then put a tracker in the rucksack of one member of each group. The DofE staff could then use aprs.fi to keep a close eye on the childrenās location during the expeditions. i would be in charge of the trackers - as they transmit my call sign - they would all just be unattended for the duration of the expeditions.
Hi Dave,
There is a thread on another reflector about using LoRA in the ISM bands for tracking - then thereās no need to use your amateur call-sign then.
Does using the ham band bring advantages over ISM? Higher power, more nodes?
73 Ed.
UPDATE: While I find it very positive that you are suggesting this help using amateur radio, there are also commercial solutions providing the tracking service, such as from this Swiss company: https://truvami.com/ this may be more acceptable to the DofE staff than a volunteer-based solution for legal, insurance or other reasons.
Thank you Ed. I did contemplate doing this, but it would not allow me to use the existing LoRA APRS infrastructure on 439.9125MHz. That said, I guess one could place an iGate in an elevated location, configure it to operate in the EU433 band, and then configure the trackers to do the same.
I think your aims are laudable Dave but I donāt think amateur radio is the correct medium for this. If you want a home rolled solution donāt use amateur callsigns and run it on ISM licence free bands. I realise that you canāt leverage the benefit of existing amateur gateways then.
The other issue is liability.
The legal implications of this are horrendous. When someone gets lost/injured etc. because they strayed in to a black spot then you are responsible so you had better ensure you have significant amounts of 3rd party liability insurance. Anyway, I cannot see school principals touching a home rolled system with a bargepole
We donāt allow SOL (safety of life) messages over SOTA spots simply because we cannot guarantee end to end delivery of messages and do not want to be liable for any failures.
As I said Dave I salute your efforts to help and as the father of a special needs person Iāll buy you a beer when I next meet you for trying to help and make things better. But I feel this is as fraught with danger as holding in the detonator on a Mills grenade with the pin removed in greasy hands.
I havenāt looked at the details of the licence changes but I assumed the unattended operation (now without a NoV) is at the address on the licence (where the transmitting apparatus is secure) and not from portable or mobile locations (where it could be tampered with or misused by an unlicensed āoperatorā).
EDIT UPDATE: It seems that UO is allowed away from the main station address. I found this statement in the Ofcom 02/2024 amateur-radio-general-notice-decision doc, paragraph 2.11 Radio equipment left unattended outside of the main station address would need to display information so that ownership of the radio can be identified by Ofcom, if required.
Assuming there is reasonable phone network reception in the target area, wouldnāt it be simpler (and less expense on radio equipment) to use the real-time location sharing feature of Google Maps. Of course, one would set the time after which the sharing becomes disabled (e.g. a few hours after the end of the event to allow for search and find).
My younger daughter did her DofE Bronze expedition a couple of weeks ago. The Explorer leader had a whole case full of trackers and gave one to each group.This is what you need rather than an amateur solution.
Thank you everyone for taking the time to reply. Point taken Andy about responsibilities, but I should add that because the children have special needs, they do have a number of LSWs (Learning Support Worker) following them at all times. Each LSW has a radio and a mobile phone, but as cellular reception can be scratchy I wondered if using the APRS network could be used as an extra level on top"; so that the coordinators could see where the group and their LSWs are.
Thank you for the suggestion Richard. I have passed the information you supplied regarding commercial DofE trackers on
Regards
Dave
P.S - Iām also wondering whether I could stick a LoRA APRS tracker to my keys and glasses - as Iām always loosing themā¦
Leaving aside the issues raised by others re the licence conditions, liability etc, I would also suspect that the coverage achieved by a LoRa solution would not meet the need, unless you can saturate local high-points with gateways or repeaters.
In SOTA we tend to be on high-points ourselves, so coverage down in the valleys is not so important to us. Your DoE charges are surely just as likely to get mislaid in a coverage blackspot as on a hiiltop.
Have a look at Meshtastic which offers all of the benefits LoRa low power spread spectrum, with a self healing mesh network. I have a several devices on 868 MHz ISM and have been watching the project mature over several years. The devices link to an app on a mobile phone using Bluetooth, but act as a tracker even without a mobile phone. Itās an interesting project to be aware of.
I have a 433 MHz APRS tracker as well as Meshtastic thingy. I did tests with those and while you get fantastic range when there is line of sight or close to it: I was on Hasenmatt HB/SO-001 and was tracked as long as I was in the non-wooded activation zone (marked green in sotl.as) from gateways as far as 70km away (even in South Germany, to which there was no line of sight) . But as soon as I entered the forest again on my way back, there was no signal anymore. Neither on the way back to the valley.
With Meshtastic (868 MHz) it is the same thing: Line of Sight ā good range. With no Line of Sight, youāre reduced to <1km at most.
So I fear that this will not work reliably for your application.
Having read a few articles on Spread Spectrum techniques Iām fascinated by their ability to coexist with narrowband transmissions. However, I understand a SS tx raises the noise floor in the bandwidth it occupies and I suspect most amateurs would object to anything that worsens the background noise on the main bands. In their (downloadable) 146-147MHz_FAQ consultation document Ofcom embraces UK amateurs experimenting with wideband digital modes including SS. āFor the true experimenters there is a wide range of spreadāspectrum, chirp and OFDM techniques which have not been tried by radio amateursā
I would be interested in doing something myself but suspect specialist transmitter hardware would be required which is very likely beyond my technical abilities.
The attraction of LoRa is that there are proprietary solutions integrated with a microcontroller available at a very reasonable price. LoRa is now mature enough, in no small part due to The Things Network, that the tricky problems have been solved and for most use cases a downloadable solution exists to use in a plug and play manner.
LoRa is low power, very low power, the spread spectrum nature of the transmission, and 1% duty cycle restriction minimise any impact for other ISM band users. Just donāt expect to send huge amounts of data. The word per minute equivalent is typically less than CW.
I have read some of the LoRa literature and concluded: 1) it doesnāt operate on an amateur band (as far as Iām aware) and 2) it appears to be aimed at Industrial, Scientific and Medical applications (like txāing low-data-rate sensor info to a base station). I would be interested only in experimenting for symmetrical digital voice/data comms between amateur stations.
As I read it, only in the 433.05 - 434.79MHz ISM allocation and according to the website I read only in Asia. That 1.74MHz allocation clashes with the RSGB band plan for FM/DV repeater outputs in the UK.
On the website I read, āLoRa (Long-Range) is digital wireless data communication IoT technology. LoRa transmits over license-free megahertz radio frequency bands: 169 MHz, 433 MHz (Asia), 868 MHz (Europe) and 915 MHz (North America).ā
The hardware can be programmed to operate over a much wider frequency range than the ISM band centred on 433.92. Thatās why there have been all the messages about LoRa based APRS nodes on here talking about 439MHz.
Even if the hardware can be programmed to transmit anywhere in the full 430-440MHz amateur band, [as I said above, and confirmed by Kevin @MW0KXN] its very-low-data rate makes it unsuitable for the digital voice/data experimentation that would interest me.
Hi Andy,
Might I suggest you look at the EZ-DV project which provides an easy way to implement FreeDV (CODEC2) on some radios (supported radios expanding as the project grows) on amateur bands (HF & V/UHF). Freedv is more normally implemented using a separate computer Windows/Linux but EZDV uses the ESP32 microcontroller to have a smaller hardware implementation, network based on those radios that support it.
FreeDV is an open-source digital voice mode that can also carry short text messages. Its advantage over SSB is that it uses less bandwidth and hence move stations can be fitted in a busy band - when signals are strong it also can have better audio quality than SSB and some other DV modes.
Theoretically by using a narrower bandwidth signals can be received at a lower signal level as the bandpass is narrower.
I believe some pre-built hardware was demonstrated at HamVention this year.
(please note this solution does not address the question about the unattended operation, which was what this thread was originally asking about, but we have gone off that topic a little (as usual)).