Video TX’s have variable power outputs as different regions have there own limits, and it’s easier for a manufacturer to make one model for multiple markets rather than different models. The responsibility is usually on the user to be compliant with their regions restrictions.
In the UK it is not illegal to buy or sell or own transmitting devices, irrespective of power output, without a license. The legality of the devices is brought into question when they are used without the appropriate authorisation. Things in the US are different. Devices can only be sold if they are FCC type approved. This is why Hobbyking have just received a fine from the FCC for $2.8m as they were selling non-type approved transmitters.
As for licensing. I’ve held a full amateur radio license for 40 or so years and I’ve used 10’s of Watts on 5.8GHz. The caveat for this is there are some spot frequencies on 5.8GHz reserved for amateur radio use BUT only for terrestrial communications, we are not allowed to install an amateur transmitter on any aerial vehicle and that includes model aircraft. But in the US, because it’s in a different ITU region they are allowed to operate higher powers for FPV if they hold a suitable amateur radio licence.
As for being nobbled by OFCOM? When I was last involved with them they had only four or five radio investigators covering the whole country. Their priorities are to the fee paying stakeholders and preserving emergency communications. Even the bastion of amateur radio no longer receives attention from OFCOM which is one of the reasons I no longer bash the key as the level of abuse is now monumental.
That side of it I understand. But all UK vendors as far as I can see are selling variable power Tx with a wink and a nod, saying "The maximum power of this may be non-legal in some countries … "
But no action seems to be taken
EDIT - this seems to have crossed in the post with @Nidge’s reply.
I remember in the old days when I was younger and no less stupid a fellow taxi-driver being threatened with court action because his radio call back to base for instructions was heard. It had the car radio playing in the background.
I knew of a shortwave listener, who was also a member of the clergy, who happened to be scanning the CB band (this was before legalisation in 1981), whom happened across a strange conversation. It turned out to be a gang about to turn over a warehouse. He called the police with the info and the gang were arrested in the act.
The following day the police turned up at his place accompanied by representatives of the Radio Investigation Services and was questioned as to why he was listening to frequencies he did not have authorisation to do so. Again it wasn’t the equipment he was using that was the legal issue but what he was doing with the equipment. The technicality that usually resulted with an illegal CB user ending up in court in those days was that the equipment they would have been using was brought into the country without Tax and Duty being paid. If the user actually admitted to using said equipment that was a bonus for the authorities.
Today it’s not the ownership of radio equipment that will land you in trouble, it’s either admitting to using it, or being proven beyond all doubt that you were using it, outside of the current rules.
As I inferred above in an earlier post OFCOM have a serious manpower issue when it comes to such transgressions. My local Ham Radio Club was once experiencing some extreme abuse from a lowlife who was continually jamming the repeater they were responsible for. The club had recordings, and the name and address of the offender, which the offender was quite happy to advertise himself. OFCOM’s response was that the club should sort it out themselves or just live with it as OFCOM had neither the time nor the resources to deal with it themselves. What they actually meant was as the amateur radio license is now free (you still have to take exams) there was no financial incentive for any action to be taken.