Amateur Radio Law (by alaric)
The radio spectrum is heavily regulated worldwide. This is because some uses of radio are matters of life and death - communications between ambulances and fire engines, air traffic control, radio navigation, GPS, distress calls from ships, military operations, aircraft/shipping radar, that sort of thing. It's easy to interfere with radio services by just happening to transmit radio waves at the frequency they're using - even accidentally, by a tuning mistake or a poor-quality transmitter that leaks energy at random frequencies - so there's a bunch of laws regulating radio transmitters in every country.
Basically, they trade off various freedoms. Operating a radio transmitter can generally be done using one of three legal approaches:
License exempt
Some frequency bands are set aside for license-exempt usage, with a quite low transmit power limit. This is where technologies like WiFi, bluetooth, wireless garage door openers / telephone handsets / baby monitors / video links, remote control, and all that sort of stuff happen. Because there is no licensing requirement, anybody can buy or build equipment that works in this area, which means:
- There's no legal protection against interference. If somebody's jamming your signals, you can't get the law to come and stop them.
- The power limits are really low, to limit the scope for trouble a transmitter can cause, which means these things are all pretty short range.
- The bands are often a bit crowded because this stuff is popular.
Two interesting license-exempt bands in the UK are the CB Radio band, allowing reasonable long-distance voice communications, and PMR used for short-range walkie talkies. Most of the others have power limits that restrict them to building-scale ranges.
Because of this, the most successful license exempt systems (Bluetooth and Wifi) tend to use clever techniques to detect interfering signals and move to other frequencies.
Normally Licensed
Most radio transmissions, and certainly any IMPORTANT ones, are licensed. That means, somebody has applied to their national radio licensing body (here in the UK, it's OFCOM) and asked for a license. That body will look at what kind of thing you want to do and decide what frequencies to give you access to, at what power limits, and in what geographical area. The latter matters because, unless you need a service that covers the entire UK, they can generally give the same frequency to different people if they won't be operating near each other.
If you're not a government body, you're probably going to have to pay for that license as long as you need it.
Also, if you find interference on your frequency, you can ring your licensing body up and they'll send engineers with radio direction finding gear to hunt it down and, generally, use scary legal powers to shut down any interference source.
Mobile phone networks use this kind of legal framework - the mobile network company holds the license, which allows you to transmit in their frequency bands under their control (by using an approved radio device under the control of a SIM card issued by the mobile network).
Usually, such licenses are pretty restrictive. The most affordable forms will state that you need to use commercial equipment built to a certain standard, often pre-programmed to use your allocated frequency and not capable of being tuned to other frequencies. This is because such licenses are designed for non-technical people - event security who want walky-talkies, taxi firms, that sort of thing. Even the licenses given to radio broadcasters, although allowing a very high power level, are just for a single frequency and transmitter location. Generally, you need to find a specific application you want a radio link for, and apply for a license to do just that; this is to minimise the chance of accidental interference with other services, while allowing the limited radio bandwidth available to be shared between the most users practically possible, by crowding them all in together.
Amateur Licensed Radio
And then we get to the odd one out: amateur radio. It still requires a license, but unlike the normal licenses, this license is pretty broad in scope: you can transmit up to quite high power levels, on a wide variety of bands, almost anywhere you like (the full UK license even lets you transmit from international waters all over the world). You can transmit whatever kind of signal you like as long as the energy is contained in the right bandwidth: speech, digital data, images, video, etc.
However, the amateur license is restrictive in two ways the other kinds aren't:
- You need to pass a technical competence test. Rather than saying "Use approved equipment", the amateur license says "Use whatever equipment you like as long as its transmissions are within legal power/frequency limits", and so, the user needs to understand how to interpret those limits, how to operate transmitters that give the user full control, how transmitters can go wrong and produce transmissions out of limits, and how to test them to ensure they don't. This gives the amateur the power to experiment (yay!), but requires them to take responsibility for not causing problems. In this respect, it's not unlike a driving license.
- You are restricted in the purposes you can use amateur radio for. It can't be commercial, you can't relay messages for non-licensed people (except in emergencies or when asked to by certain government-authorised bodies), you can't broadcast except under limited circumstances.
The latter point is the interesting one, and has some interesting consequences.
No commercial operation
Mainly, this is to stop amateur radio being too useful and people getting amateur licenses just so they have a good communication system. You might imagine a company wanting handheld radios for their staff perhaps sending all the staff on foundation amateur radio courses (which take about a weekend) then letting them use cheap £20 VHF transceivers such as the excellent Baofeng UV-5R to talk, all over the country, at high enough power levels to be heard to the horizon and beyond. This would be cheaper than getting a commercial radio license with such broad scope, but if companies were allowed to do that, not only would the limited bandwidth allocated to amateur radio in the VHF spectrum get pretty busy with boring commercial chatter, more importantly, OFCOM would be missing out on all that sweet, sweet, license fee revenue.
You can't relay messages for non-licensed people (except...)
Even on a voluntary basis, amateur licensed folks might be tempted to be helpful to others by relaying messages for them via radio; they're not allowed to use the transmitter themselves without a license, but somebody with a license could just repeat the message for them - and then an unlicensed person could listen on a receiver to get the message. That'd be neat, right?
Except, again, letting amateur radio be too useful would lead to the limited spectrum being used for that stuff, crowding other uses out, and deprive OFCOM of delicious license fees. So the rule is that amateur radio transmissions must not relay messages from non-licensed folks, and must be transmitted to licensed users (although anybody is welcome to listen along, they are eavesdroppers and can't be the target of the transmission).
However, there's a caveat that you CAN relay messages from government-authorised folks such as emergency services, and a long list of other government bodies, and their appointed people. In practice, this means that you can do useful community volunteer stuff if it's blessed by local government agencies, which basically means that it only happens for events big enough for them to be involved, which nicely rate-limits such activity so it doesn't become a problem.
No broadcasting (except...)
So, the rules in the UK say that "messages" must be from an amateur to another amateur, except for initial "Is there anybody out there I can talk to?" requests, and for communication in a group where you can address the group as long as you've introduced yourself to the group first. As far as I can tell, this is just a "Don't let amateur radio get too useful or it'll be taken over by boring things" measure.
However, the rules also say you can transmit "beacons" (subject to certain restrictions) and it seems that "beacons" don't count as messages. This is most notably used in APRS where you can broadcast digital packets with your location and other information in, including arbitrary text messages.
As far as I can tell, anything you'd actually usefully want to broadcast (to other amateurs) is called a "beacon" and anything sent to an individual or a currently-chatting group of individuals is called a "message", so there isn't really a restriction against broadcasting... but I think it's implied that beacons must be digital in nature (perhaps because a beacon has to be low-bandwidth and low-duty-cycle), you can't "beacon" by speaking? Or something? It's a little vague, and in practice, interpreted liberally as long as you don't cause any trouble.
Would I do it any differently?
I sometimes find myself frustrated by the limits on what radio experiments I can do with my UK license. But, I reckon, the overall gist is about right - making it accessible for inventors such as myself to play with, while not making it so useful that the bands will be crowded with boring things, is a tough call.
I think a few tweaks could be made - for instance, I think radio amateurs should be allowed to transmit in license-exempt bands such as CB and PMR as long as we operate within the power limits of that band; we are already licensed to build our own equipment to comply with legal limits, and it's just wasteful that I'm not allowed to transmit on CB and PMR frequencies using my capable multi-purpose transmitters, instead having to buy separate approved transmitters. The signal I'd output would be identical. And being allowed to set up remote control links between things I own would be kinda useful for some things I want to do (the American amateur license allows this!)
But I reckon the current system is... probably about right!
Mon 2nd Nov 2020 1:13 pm 
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