Retrotechtacular: 934 MHz CB Radio

The radio spectrum is carefully regulated and divided up by Governments worldwide. Some of it is shared across jurisdictions under the terms of international treaties, while other allocations exist only in individual countries. Often these can contain some surprising oddities, and one of these is our subject today. Did you know that the UK’s first legal CB radio channels included a set in the UHF range, at 934 MHz? Don’t worry, neither did most Brits. Behind it lies a tale of bureaucracy, and of a bungled attempt to create an industry around a barely usable product.

Hey, 2019, Got Your Ears On?

Did this car make you want a CB radio? Stuurm [CC BY-SA 3.0]
Did this car make you want a CB radio? Stuurm [CC BY-SA 3.0]
Mention CB radio in 2019 it’s likely that the image conjured in the mind of the listener will be one from a previous decade. Burt Reynolds and Jerry Reed in Smokey and the Bandit perhaps, or C. W. McCall’s Convoy. It may not be very cool in the age of WhatsApp, but in the 1970s a CB rig was the last word in fashionable auto accessories and a serious object of desire into which otherwise sane adults yearned to speak the slang of the long-haul trucker.

If you weren’t American though, CB could be a risky business. Much of the rest of the world didn’t have a legal CB allocation, and correspondingly didn’t have access to legal CB rigs. The bombardment of CB references in exported American culture created a huge demand for CB though, and for British would-be CBers that was satisfied by illegally imported American equipment. A vibrant community erupted around UK illegal 27 MHz AM CB in the late 1970s, and Government anger was met with campaigning for a legal allocation. Brits eventually got a legal 27 MHz allocation in November 1981, but the years leading up to that produced a few surprises.

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British Cops Catch Shooter-Printing Villain

It’s a perennial of breathless British tabloid scare reporting that 3D printers will unleash a tide of weapons upon the streets. But perhaps it might actually be time for Brits lock up their children, because London’s Metropolitan Police have announced their first prosecution for 3D printing a handgun. The gun pictured appears to be a Repringer 5-shot .22 revolver, and was found by police during a drugs raid.

The UK has significantly restrictive firearms legislation and shooting incidents are extremely rare in the country, so while this might not raise any eyebrows on the other side of the Atlantic it’s an extremely unusual event for British police. It appears that the builder was not the type of libre firearms enthusiast who has made the news with similar work in the USA, so it has to be assumed that it was printed purely as a means to secure an illegal firearm however rough-and-ready or indeed dangerous it might be.

Stepping aside from the firearm aspect of the story, it should be of concern for any British 3D printer enthusiasts. As we’ve reported over the years with respect to drone incidents they can sometimes throw reason to the wind when faced with unfamiliar technology, indeed we’ve already seen them imagining RepRap parts to be for a firearm. We’d counsel all parties to keep sane heads, and hope that both the sentence for today’s criminal proves to be a suitable deterrent, and that no clueless fool decides to download and print another weapon for the hell of it. As always, we’ll bring you developments as they happen.

Drone Registration Tax Sought By UK’s CAA

As the UK’s aviation regulator, the Civil Aviation Authority is tasked with “making aviation better for those who choose to fly and those who do not”. Their latest plan to further this mission comes in the form of a drone registration tax. The proposal, which is open to online responses until 7 June, seeks to pass on the cost of a drone registration system to those who register themselves.

Proposals for a drone registration scheme have been in the works for a while now, and if enacted it would go into effect on 1 November. Owners of craft weighing more than 250 g (0.55 lbs) would have to fork out £16.50 ($21.50) per year, ostensibly to pay for the administration of the scheme. The CAA are basing this rate on as many as 170,000 people registering. In the US, the FAA has a drone registration program in place that requires registration based on the same 250 g weight guideline, but only charges $5 (£3.82) for a 3-year license, about thirteen times less than the CAA proposal.

Long-time readers will be familiar with our ongoing coverage of the sometimes-farcical saga of drone sightings in British skies. Airports have been closed (and implausible excuses have been concocted), but one thing remains constant: no tangible proof of any drone has yet been produced. Faced with a problem it doesn’t fully understand, the British Government is looking to this registration program.

It goes without saying that people misusing drones and endangering public safety should be brought to justice as swiftly as possible. But our concern is that the scale of the problem has been vastly over-represented, and that this scheme will do little to address either the problem of bogus drone sightings or the very real problem of criminal misuse of drones for example to smuggle contraband into prisons. It’s difficult to think this measure will have an effect on the number of incidents blamed on drones, and the high cost included in the proposal is a troubling burden for enthusiasts who operate responsibly.

A Peek Inside A Typical British Residential Power Panel

No matter what field you’re in, it’s interesting and instructive to find out how others practice it. That’s especially true with electrical distribution systems, where standards and practices differ from country to country and even between regions. This tour of a typical British residential electrical panel is a great example of the different ways that the same engineering problems can be solved, and the compromises that always attend any design.

We’re used to seeing [Big Clive] tearing interesting devices to bits, but rest assured that this electrical panel remains largely intact as it gives up its secrets. Compared to the distribution panels and circuit breakers common in North American residential construction, the British consumer unit is a marvel of neatness and simplicity. True, the unit on display hasn’t been put into service yet, and things will no doubt change once an electrician is through with it, but the fact that everything is DIN rail mounted is pretty cool. [Clive] explains a few of the quirks of the panel, such as the fact that what looks like a main breaker is in fact just an isolation switch, and that there are a pair of residual current devices (RCDs), which we call ground-fault circuit interrupters (GFCIs) in North America, that also don’t act as circuit breakers, despite appearances. A stout bus bar is provided to link the RCDs to adjacent circuit breakers, forming two groups that are separately protected from ground faults.

[Clive] notes with dismay that the lugs of the bus bar can actually be inserted behind the rising clamp terminal on the breaker, resulting in poor connections and overheating. Still, we wouldn’t mind some of these concepts brought to panels in North America, which we covered a bit in a discussion on circuit protection a while back.

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Britain Rejoins The Space Race

Jubilant crowds at the gates of Downing Street. (Jenny List)
Jubilant crowds at the gates of Downing Street. (Jenny List)

In a completely unexpected move, the British Prime Minister Theresa May yesterday announced outside Number 10 Downing Street that the UK would resume its space launch programme, 47 years after its cancellation following the launch of the Prospero satellite. She outlined a bold plan with a target of placing the Doc Martens of a British astronaut on the Lunar surface as early as 2024. Funded by the £350m per week Brexit windfall, the move would she said place the country at the forefront of a new 21st century Space Race with the North Koreans.

An estimated 2 million jubilant supporters took to the streets of London at the news, bringing the capital to a halt as they paraded with colourful banners from Hyde Park to Trafalgar Square and down Whitehall past her Downing Street home. Meanwhile the value of shares in the popular British high street bakery firm Patisserie Gregoire jumped by 19% as it was revealed that their new vegan sausage roll had in fact been a secret trial of the British astronaut diet. Continue reading “Britain Rejoins The Space Race”

UV Glow Clock Tells The Time Glowingly

Reddit user [TuckerPi] wanted to make something to thank his father for helping him get through his engineering degrees. He hit it out of the park with this awesome glowing clock. The clock uses a strip of UV glow tape, which is rotated by a small stepper motor. On one side a UV LED is moved up and down by a second motor to make the tape glow underneath it. A Raspberry Pi drives the whole system, writing the time on the tape and rotating it to face outwards. Once a minute the clock rewrites the time on the rubber.

This is a lovely build that shows what [TuckerPI] learned in college, as he built most of the mechanism himself, cutting his own metal gears and parts and making a nice, simple case from African mahogany. He also shows his mistakes, such as his first attempt to build the glowing mechanism from silicon rubber mixed with UV powder. Although it worked initially, he found that the UV powder fell out of the rubber after a short while, so he replaced it with UV glow tape.

[TuckerPi] hasn’t published the full schematics of the device, but there is a lot of detail in the Imgur photos of the build and in the Reddit thread where he discussed the build. Kudos to him for finding an interesting and unique way to thank his father for his help.

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Hacking When It Counts: The Magnetron Goes To War

In 1940, England was in a dangerous predicament. The Nazi war machine had been sweeping across Europe for almost two years, claiming countries in a crescent from Norway to France and cutting off the island from the Continent. The Battle of Britain was raging in the skies above the English Channel and southern coast of the country, while the Blitz ravaged London with a nightly rain of bombs and terror. The entire country was mobilized, prepared for Hitler’s inevitable invasion force to sweep across the Channel and claim another victim.

We’ve seen before that no idea that could possibly help turn the tide was considered too risky or too wild to take a chance on. Indeed, many of the ideas that sprang from the fertile and desperate minds of British inventors went on to influence the course of the war in ways they could never have been predicted. But there was one invention that not only influenced the war but has a solid claim on being its key invention, one without which the outcome of the war almost certainly would have been far worse, and one that would become a critical technology of the post-war era that would lead directly to innovations in communications, material science, and beyond. And the risks taken to develop this idea, the cavity magnetron, and field usable systems based on it are breathtaking in their scope and audacity. Here’s how the magnetron went to war.

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