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Comment by w0mbat | Hacker News Reader

This is a story I heard when I worked at the BBC. Years ago the BBC had many reports of bad reception in a certain part of the UK. Eventually they traced it to a isolated house near a BBC broadcast tower. The resident had rigged up a big induction coil on his property and he was leaching hundreds of watts from the tower's transmissions. He was using the power to run his house lighting "for free", not realizing he was casting a huge detectible shadow. The story says that he was prosecuted.

If anybody has any hard details or can confirm this BBC legend it would make me very happy.

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It’s definitely a legend. The amount of usable power you can extract from a radio signal is minuscule even fairly close to a transmitter. The incident radiation on his property was definitely nowhere even near watts let alone hundreds of watts. Nor would an induction coil or any sort work with respect to power transfer unless it was magnetic coupling.

People seem to think of radio waves as a magical power transfer medium but it’s terrible for that. It’s only really useful for information and no magic stories or hype will be changing that.

I thought you were about to tell this story, where an old TV messed up the village internet.

https://arstechnica.com/information-technology/2020/09/old-t...

I heard of a similar story when taking a tour of a local transmition station as a kid. You can light up fluorescent tubes by placing them on the ground under high voltage power lines, so I'd assume something like that is how this would work:

https://www.theguardian.com/science/2004/feb/26/thisweekssci...

https://m.youtube.com/watch?v=cXhZvyGtMrk

Many many moons ago, when I hung out in a group that ran CBs with linear amps, we used to win bets with people by saying that we could light up a florescent bulb without any kind of power source... which we did by holding the bulb near the CB antenna and keying up.

you won the bet...by using a power source? :)

They were swindlers, raking in hundreds in cash using scientific knowledge that was indistinguishable from magic to lesser educated minds.

a wireless power source if you will

My dad had a story about this happening by accident at his workplace.

There was a lightbulb which wouldn’t switch off. Electrician came in, tested the switch, very confused, took the glowing light out of its socket and it still continued to shine.

I'm sorry to say that putting a coil near a tower would only leech what passed through it, so unless the coil was nearly the same size as/bigger than the tower, and right beside it, and the coil was directly in line with the folks reporting bad reception, this is probably a tall tale.

Wouldn't the coil emit the opposite induced field?

Yes, definitely, but only to the degree that you actually consume it's generated power.

Not true, the coil emits its own radio waves which are exactly 180 degrees phase shifted with respect to the radio tower. Destructive interference could be measured behind the coil, even when not exactly in its shadow.

Surely a HF signal is targeted at the horizon and in the event someone close enough did attempt to gather what I imagine would be a handful of Watts via induction they wouldn't be a target of the RF energy so it wouldn't really even work. You'd likely need close proximity like of sight to the mast if have thought

The BBC transmitter in the story was either medium wave, or perhaps more likely long wave, Radio 4.

Really? Because since the 1950s any towers I know of broadcast a range of services that almost always include analogue TV on UHF

This was analogue radio not television.

Along the lines of looking for "detectible shadows", I wonder if "Wardriving for jammers" would prove interesting in Silicon Valley today. Similar to wardriving for WiFi in the early 2000s.

Probably not. Signal jammers are illegal to sell, use, or advertise. You wouldn't find very many.

https://www.gps.gov/spectrum/jamming/

Most people/companies aren’t deliberately causing jamming or interference. But there are consultants that will help isolate these accidents so the issue can be resolved. Unfortunately the name of the company that does this is failing me right now.

I think when I heard it (from a radio ham in the 80s) he was using bales of fence wire in his loft as his coil. Still that detail about powering the lights (not the whole house) though.

Hams used to put light bulbs on the end of their antennas to light up when they keyed down due to the standing wave on the antenna having high voltage at the end. I suspect that was part of the illusion and the story. It is however pointless and frowned upon as it’s actually detuning the antenna.

The version I heard was a farmer where high voltage lines were run through his property and to get back at the power company he buried a large coil of wire directly under the HV lines to power some of his house.

That wouldn’t work either.

People’s misunderstanding of mutual inductance does not surprise me really.

Sharing stories and getting laughs is more important than having every statement uttered in a conversation be literally true. My radio ham friend had some outrageous whoppers.

Oh yes completely. Half of ham radio is stories of the one that got away and that contact you made when your antenna was broken.

it's a news organization, they are rewarded for getting views, not getting the story straight. for more information on that see how Orson Welles went bankrupt. big media is a bigger threat to society than big oil and the islamic state combined. if people remember right, corporation's were super anti internet because of competition. so if you think facebook/apple/whatever is bad, you were obviously born sometime after the 90s, not being mean, its kinda the way things were, there are people who want to restore that order, but technology happens and old establishments have to accept that they can either fight the new establishment or evolve

The BBC isn’t a typical organisation, it is a public broadcaster created by the British government.

Plenty of flaws (is anything ever otherwise?) but it does try to aim at public interest more than eyeball count.

Yeah, the BBC doesn't have quite the same motivations as commercial broadcasting. To be honest it's pretty good if you take it with the caveat it'll always be at least mildly biased not to the left or right but towards the British establishment of the day. They're definitely not as bad for literally just making shit up to get eyeballs on ads compared to many of the commercial offerings.

Being a public broadcaster also means they can serve niche interests in a way that commercial broadcasters can't. For example, they maintain a powerful longwave service so that small and older boats can still get the shipping forecast when they're out of VHF range (and so people who haven't - reasonably enough in my opinion - adopted DAB can listen to the cricket!). They're also one of the most influential international broadcasters, it's nice always having the BBC World Service available in most places I've travelled to even if it's a bit more transparently an instrument of British soft power than the domestic service.

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