If you paid attention to advertising in 1980s Britain, you were never far from Economy 7. It was the magic way to heat your house for less, using storage heaters which would run at night using cheap electricity, and deliver warmth day-long. Behind it all was an unseen force, a nationwide radio switching signal transmitted using the BBC’s 198 kHz Long Wave service. Now in 2025 the BBC Radio 4 Long Wave service it relies on is to be turned off, rendering thousands of off-peak electricity meters still installed, useless. [Ringway Manchester] is here to tell the tale.
The system was rolled out in the early 1980s, and comprised of a receiver box which sat alongside your regular electricity meter and switched in or out your off-peak circuit. The control signal was phase-modulated onto the carrier, and could convey a series of different energy use programs. 198 kHz had the useful property due to its low frequency of universal coverage, making it the ideal choice. As we’ve reported in the past the main transmitter at Droitwich is to be retired due to unavailability of the high-power vacuum tubes it relies on, so now time’s up for Economy 7 too. The electricity companies are slow on the uptake despite years of warning, so there’s an unseemly rush to replace those old meters with new smart meters. The video is below the break.
The earliest of broadcast bands may be on the way out, but it’s not entirely over. There might even be a new station on the dial for some people.
I have a modern but non-smart economy 7 meter for overnight car charging. I think it keeps track of time itself, maybe counting 50Hz cycles the old fashioned way. When the clocks go forwards or backwards, the e7 hours shift + or – one hour. When it was first installed, it was displaying the wrong time. They had to replace the whole meter to fix it!
Could they not put a secret line of dialogue in the Archers such as “The potatoes are early this year” on FM, which gets analysed by the meter and switches the meter?
I can’t properly express how clever I think that is. Thanks for the chuckle.
Sad, these things were actually reliable compared to the internet. :(
Btw, wouldn’t it be possible to have an 198 KHz RF signal being modulated on the AC line directly?
So the receivers might react to it, due to irradiation?
Every transformer in the distribution system would act as a choke, filtering out the signal.
Yes, but wouldn’t the remaing wires still act as aerials?
These are long wave receivers, they can pick up weak signals in the distance, still.
If the power lines of the street lanterns or the tram would radiate the 198 KHz signal,
maybe there would be a chance it could act as a makeshift antenna system?
I always wondered how secure these things were. What’s to stop me generating my own local signal to switch it over first thing in the morning so I can enjoy off-peak energy all day?
“What’s to stop me [..]”
Laws? Your conscience? Social behavior you’ve (hopefully) lernt by your parents? Sense for right/wrong? 🤔
Could be an extremely short range signal placed right next to it
Yes, an oscillator without any antenna.
Problem is range, though. Long wave signals follow ground and easily travel through walls, they don’t need direct sight like VHF signals would need.
A low power transmitter (a few dozen milliwatts) might be still strong enough to be heard in a 100m radius by radio-controlled clocks with their sensitive receivers.
So in order to weaken things down even more, a dummy load (terminator) and a ferrite coil would be needed.
A normal air coil might be too efficient already.
Using a coin cell as a power limiting factor would be wise, too.
A 9v battery might be too strong already.
If this seems to extreme, please consider how a distant low-power a weather station sensor can be placed from weather station, for example.
It’s still remarkable, considering the power source.
Such does not carry stopping power but rather social influence for consideration Before ultimate decision by a conscious mind.
What a person’s exposed to provides options and how a person is raised provides a template. But to be human is to be self programmable. To be conscious is too question that which you are raised. To be alive is to be curious. Unless you think humans are little more than trainable dogs or robots. Personally I don’t think we are so little as whatever social muck we are raised to be.
That’s what computers are for. They are what we make them to be. Humans are born with an instinctive urge to invalidate that which they started from and replace it with self creation.
You know the name of this website right?
Seriously, there’s no “security” in hardware. 😟
These mechanisms were made in a different time, without the assumption
that the own citizens are destructive or dangerous to the public.
Radio-controlled clocks have no security mechanism, either.
You can transmit your own signal, with all the consequences it has.
If you’re transmitting a false time or date “just for fun”,
then the citizens in your neighborhood may not wake up at correct time.
An alarm clock of a kindergarten teacher or doctor won’t buzz in the morning, for example, cause them to oversleep. Fun isn’t it?
You can also put a potato in the exhaust of a neighbor’s car and see “how secure” it is against sabotage. Same fun.
I did just that to that one nouveau riche kid who once in a blue moon made a mistake of leaving “his” (that is bought with daddy’s money) almost brand new BMW modified with a “popper” exhaust outside overnight.
Except it wasn’t a potato but Soudal polyurethane foam (same stuff used in construction to mount doors or windows) delivered through extra-long hose to make sure it really fills the exhaust system. Oh the lulz in the morning when this little spoiled brat realized his precious car is going nowhere but straight to workshop.
The repair must’ve been expensive because since then there was no more popping in the neighborhood.
That’s just evil. I love it.
Ah, things that could be done before dashcams…
That being said, there of course had been some people in the past who were silly enough to toy with such technology, they were no saint whatsoever.
Some electronics magazine surely had printed an article about it, too.
But that was for sake of curiosity, to impress friends etc.
But not for serious use. They knew what’s right and wrong.
I’m thinking about my dad’s generation, here. They were crazy.
His CB radio friends were doing quite some silly things.
That’s a lot of replying… I was more asking whether there were any technical safeguards in place, rather than looking for a lesson in ethics and human behaviour.
Hi, sorry, I didn’t mean to “educate” anyone.
My point simply was the difference in mindset.
It’s unlikely that these old systems had any kind of encryption,
a special pulsing pattern that changes over time etc.
Back in the day, public systems were.. public systems.
There was not that much secretcy about their function etc.
Or so I think, at very least.
You could even listen to police radio, it wasn’t encrypted.
Just forbidden by law to listen to it.
But if you did by accident, you just had to pretend you didn’t hear it.
(In my country at least, not sure about GB/UK.)
Or in other words, due to lack of “criminal energy” of citizens,
a security system likely wasn’t needed at the time.
Especially since these systems were not considered critical systems.
The thinking of 21th century is in stark contrast to the past here, of course.
We now have a level of terr*rism that wasn’t imaginable at the time.
Except when it comes to phone booths, maybe. There was quite some vandalism early on.
This is/was usually used for things like storage heaters and water heaters (ie, use cheap electricity to heat up a big thermal mass), so you’d end up getting pretty warm.
A friend of mine worked in “compliance” for one of the electricity companies. They were very good at spotting this kind of stuff, and many other shenanigans people tried. They mainly went for businesses who were stealing power, so it’s possible you’d fly under the radar if you didn’t steal much energy…
When they went out to enforce, they were often accompanied by armed police because often energy thieves are part of OCGs.
“to be retired due to unavailability of the high-power vacuum tubes it relies on”
Feels like a FET circuit in a tube form factor wouldn’t be that hard?
100 kW FET?
Or to just find a university lab with a scientific glassblower and a high vacuum pump. It’s just glass and metal, make a new one.
So this is it, the next Trident sub to surface, on hearing no Radio 4, will nuke Moscow.
It will have to wait until the 7pm episode of The Archers (see above).
“comprised of…”
Ugh.
Should be “comprised…” or if you’re in love with the word “of”. “consisted of…”
/takes grammar pedant hat off, blends back into the crowd
Yes (although it would be “consisting of…”…).
You could also write “composed of…”, and I suspect that’s the connection that trips people up so often with “comprise”.
It’s tempting to say you should check the dictionary when in doubt, but of course the problem is when a writer doesn’t have the doubt to begin with.
That’s why it is a public service to prod people about these things. It’s not snooty (necessarily), it’s helping keep the language in good repair for the benefit of new and future speakers.
No, there was no security in such things. I still remember the time I decided to turn on all of the lights connected to X-10 switches in my entire apartment court. And I remember the blood-curdling woman’s scream as she was terrified that someone was there in the apartment with her. I didn’t do that again.