Crystal sets - are legal for receiving broadcast stations - as they are nothing other than a 'tuned receiver' doing what they are meant to to do and do not leach (meaningful amounts of) power from the air.

In the UK you are only licenced to receive broadcast radio signals (yes; the government 'holds' your receiving licence for you; even today; even in this day and age) - note that it does not matter WHAT is being broadcast (AM; FM TV DAB etc). Use of radio receiving apparatus for any other purpose (unless explicitly licenced eg CB PMR HAM) is illegal.

Using radio signals to generate electrical power is theft. In the '60s a guy near Rugby Radio was done for the following :

1. Illegal unlicenced reception of radio signals, resulting in the confiscation of ALL radio receivers/equipment and associated bits and pieces - which included lights and a couple of low power items he had connected up.
2. Theft of electricity from the GPO; MoD (Navy) BBC (domestic & world service) - massive fine PLUS he had repay the estimated amount of electricity stolen (some 5 years worth), calculated on the basis that he was using the maximum amount of power "generated" (stolen) 24x7. It was only a few 100 watts - but it did add up!
3. Defrauding the MEB (Midlands Electricity board) of the money he SHOULD have paid for the electricity stolen - for which he was fined AND had to pay back the estimated amount.

All of which got him a criminal record.

And, if memory serves, in the '60s one still needed a licence to listen to the (broadcast) radio if there was not a valid TV licence for the premises. Failure to have one for one's premises was (and for TVs in the UK is still) criminally illegal with a £1000 fine.

There have been a (smallish) number of successful prosecutions of people (mainly farmers "stealing electricity" from nearby transmitters). One example that springs to mind was a farmer whose cowshed was 200m from the 198Khz BBC Radio 4 transmitter. He lit the shed with some fluorescent tubes with bits of wire on each end acting as antennae (or electricity pickups as, I believe, the prosecution called them).

You could consider putting little NFC devices into the chip in bank and credit cards, so that you can do "contactless" transactions (say up to $50) JUST WITH THE CARD. Like most of the rest of the developed world.

The Dutch Institute of Health is also waste water streams at individual sewage plants all over the Netherlands.

Your oven works at 2.45Ghz (nominally), these are microWaves (but actually UHF). Some 4G can be found in the 3-6GHz area - these are still microwaves (but we have now strayed into SHF). 5G is currently slated to use 24Ghz and then higher frequencies, but 24 Ghz is really ~1.25cm, we don't really get into millimeters or mmWaves until beyond 30Ghz (the start of EHF).

But don't let any facts get in the way of a marketing slogan or trademark!

Three things:

1. Today I can buy 250w panels in the UK for ~79cents/watt, or a little under $9500 for 12KW at today's exchange. Bearing in mind that the price that you or even I pay is likely to considerably higher than the price of panels in "third world countries" - for the same reasons that power is cheaper. At MW scale the price is even lower.

2. I am not necessarily advocating panels on housing (although Germany is currently experimenting with estate built housing all with solar roofs and also estate battery systems (but not necessarily on the same estate)). If you visit Germany, you see MW sized solar panel systems built on all sorts of otherwise marginal land - all over the country. Here in the UK, it is actually more profitable to farm MW sized solar panels than crops on anything less than grade 2 land and there are many 100s of such installations all over the country, even though the UK has notoriously erm.. variable weather. Imagine what could be done in countries in sunny climates.

But the point is that increasing scale pushes the overall price down and, crucially, balances the majority of the aircon load - reducing the overall emissions for aircon is a happy by product.

3. In India, even dyed in the wool coal fired power plant companies are seeing the writing on the walls and are actively building double (and a few triple) digit solar plants. There must be money to be made here otherwise they would not bother.

Why do hot (and therefore sunny) countries not make a point of powering their air conditioning systems with solar panels? Given a COP of around 4 on modern systems, it should be possible to do this both economically and not using too much real estate. Even if power is required out of daylight hours, the panels should bear the brunt of the load.

For a slightly more modern take, this book is still relevant even today: https://ancillary-proxy.atarimworker.io?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2F.... Maybe someone read it recently - it is still a useful book.

What is this thing called a "record"? What possible use is it? Or could it be a new name for an old concept that might have existed in some ancient cruddy languages. Cobol anyone?

And neither have Instagram, Messenger and the rest of them. GDPR requires that the data subject gives explicit consent, separately, to each use of their data. This really powerful stuff and, at the same time, totally alien to FB, Google et al. It isn't even as if the words in the regulations are unclear or writing in high faluting legalese:

Article 7.

1.Where processing is based on consent, the controller shall be able to demonstrate that the data subject has consented to processing of his or her personal data.

2.If the data subject's consent is given in the context of a written declaration which also concerns other matters, the request for consent shall be presented in a manner which is clearly distinguishable from the other matters, in an intelligible and easily accessible form, using clear and plain language. Any part of such a declaration which constitutes an infringement of this Regulation shall not be binding.

This is likely also to cause quite a bit of erm... inconvenience to the sellers of data. Methinks there will be much merriment amongst the legal profession in the EU over the next couple of years.

The fact that it all seems to be going in the right way - for now - does not mean it will continue. Many e-commerce jobs for humans will be destroyed in the next few years as e-commerce gets more and more automated. Yes there will be jobs, but for far fewer and better qualified/skilled people. If you are a relatively unskilled worker - in my view - your prospects are not going to be good. And, what is worse, it will be people like us that are facilitating this.

Don't even start me on what robotics are going to do to the trucking industry...

Apart from Uber and one or two others? Come to that, will Ford, GM, VW et al still exist as separate car giants in 30 years time? They'll all be sub-contracting to the people who will be hiring out individual transport to take you from place to place in a vehicle that you hire by the hour. Very, very few people will own their own cars. Still less drive them - except for those "quaint" early 2000's models - on special tracks to which they will be transported safely (on specially designed flat beds) by - yep, you've guessed it. Dear old Uber. I imagine the wrecks will be returned by different flatbeds :-)

Because when you get small children (say 2-4 y.o not yet schooling) that speak different languages playing together - they will invent new terms and language to share concepts between themselves. I know, I was one of those children, whose long suffering parents were getting constant complaints from other parents saying that they could not understand their children. My parents comforted themselves by agreeing with them - because they couldn't understand me either. This is how language happens. Get over it.

At Galdor we had an ICT-1301 in a purpose built building in the back garden of the house we lived in. It was built in 1961 and given the name "Flossie" by the manufacturers. She still exists and is waiting to be restored to working order, for the fourth time, at the National Computing Museum at Bletchley Park.