A Dangerous Demonstration Of The Power Of Radio

Terrestrial radio may be a dying medium, but there are still plenty of listeners out there. What would a commute to or from work be without a check of “Traffic on the Eights” to see if you need to alter your route, or an update of the scores from yesterday’s games? Getting that signal out to as many listeners as possible takes a lot of power, and this dangerous yet fascinating demo shows just how much power there is on some radio towers.

Coming to us by way of a reddit post, the short video clips show a crew working on a 15,000-Watt AM radio tower. They appear to be preparing to do tower maintenance, which means de-energizing the antenna. As the engineer explains, antennas for AM radio stations in the medium-wave band are generally the entire tower structure, as opposed to the towers for FM and TV stations, which generally just loft the antenna as high as possible above the landscape. The fun starts when the crew disconnects a jumper and an arc forms across the clamp and the antenna feed. The resulting ball of plasma acts like a speaker, letting us clearly hear the programming on the station. It’s like one of the plasma speakers we’ve seen before, albeit exceptionally more dangerous.

It’s an impressive display of the power coursing through broadcast towers, and a vivid reminder to not mess with them. Such warnings often go unheeded, sadly, with the young and foolish paying the price. There’s a reason they put fences up around radio towers, after all.

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Texas Tesla Tower Titillates

One of the nice things about a road trip is you often get to see something that really surprises you. A recent trip through Texas may have resulted in my second most surprising sighting. There’s a strange tower that looks oddly like a Tesla tower in the middle of rural Texas, right off the main interstate. What is it? Although Google did answer the question — sort of — I’m still not sure how legitimate its stated purpose is.

First Sighting

I was driving between Wimberly and Frisco — two towns that aren’t exactly household names outside of Texas. Near Milford, there’s a very tall structure that looks like a giant mechanical mushroom on top of a grain silo. If the mushroom were inverted or pointing towards the horizon, it would be easy to imagine it was some very odd antenna. This dish, however, is pointed right down its own odd-shaped mast. The top of the thing sure looks like the top of a Van de Graf generator.

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The Final Days Of The Fire Lookouts

For more than a century, the United States Forest Service has employed men and women to monitor vast swaths of wilderness from isolated lookout towers. Armed with little more than a pair of binoculars and a map, these lookouts served as an early warning system for combating wildfires. Eventually the towers would be equipped with radios, and later still a cellular or satellite connection to the Internet, but beyond that the job of fire lookout has changed little since the 1900s.

Like the lighthouse keepers of old, there’s a certain romance surrounding the fire lookouts. Sitting alone in their tower, the majority of their time is spent looking at a horizon they’ve memorized over years or even decades, carefully watching for the slightest whiff of smoke. The isolation has been a prison for some, and a paradise for others. Author Jack Kerouac spent the summer of 1956 in a lookout tower on Desolation Peak in Washington state, an experience which he wrote about in several works including Desolation Angels.

But slowly, in a change completely imperceptible to the public, the era of the fire lookouts has been drawing to a close. As technology improves, the idea of perching a human on top of a tall tower for months on end seems increasingly archaic. Many are staunchly opposed to the idea of automation replacing human workers, but in the case of the fire lookouts, it’s difficult to argue against it. Computer vision offers an unwavering eye that can detect even the smallest column of smoke amongst acres of woodland, while drones equipped with GPS can pinpoint its location and make on-site assessments without risk to human life.

At one point, the United States Forest Service operated more than 5,000 permanent fire lookout towers, but today that number has dwindled into the hundreds. As this niche job fades even farther into obscurity, let’s take a look at the fire lookout’s most famous tool, and the modern technology poised to replace it.

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Emergency Cell Tower On A Budget

Cell phone towers are something we miss when we’re out of range, but imagine how we’d miss them if they had been destroyed by disastrous weather. In such emergencies it is more important than ever to call loved ones, and tell them we’re safe. [Matthew May] and [Brendan Harlow] aimed to make their own secure and open-source cellular network antenna for those occasions. It currently supports calling between connected phones, text messaging, and if the base station has a hard-wired internet connection, users can get online.

This was a senior project for a security class, and it seems that the bulk of their work was in following the best practices set by the Center for Internet Security. They adopted a model intended for the Debian 8 operating system which wasn’t a perfect fit. According to Motherboard their work scored an A+, and we agree with the professors on this one.

Last year, the same SDR board, the bladeRF, was featured in a GSM tower hack with a more sinister edge, and of course Hackaday is rife with SDR projects.

Thank you [Alfredo Garza] for the tip.

Life-Size Vu Meter Gets The Party Started

There’s nothing better than making a giant version of one of your hacks. That is, other than making it giant and interactive. That’s just what [Est] has done with his interactive VU meter that lights up the party.

The giant VU meter boasts a series of IR detectors that change the colors and modes of the meter based on where the user places their hands. The sensors measure how much light is reflected back to them, which essentially function as a cheap range finder. The normal operation of the meter and the new interactivity is controlled by a PIC16F883 and all of the parts were built using a home-made CNC router. There are two addressable RGB LEDs for each level and in the base there are four 3 W RGB LEDS. At 25 levels, this is an impressive amount of light.

[Est]’s smaller version of the VU meter has been featured here before, if you’re looking to enhance your music-listening or party-going experiences with something a little less intimidating. We’ve also seen VU meters built directly into the speakers and also into prom dresses.

A Field Guide To The North American Communications Tower

The need for clear and reliable communication has driven technology forward for centuries. The longer communication’s reach, the smaller the world becomes. When it comes to cell phones, seamless network coverage and low power draw are the ideals that continually spawn R&D and the eventual deployment of new equipment.

Almost all of us carry a cell phone these days. It takes a lot of infrastructure to support them, whether or not we use them as phones. The most recognizable part of that infrastructure is the communications tower. But what do you know about them?

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Building An Advanced Mobile Phone Service (AMPS) Base Station

Remember the early days of cellphones and carphones when they were super-bulky and all the rage? Those early handsets used analog technology for communications in a protocol called Advanced Mobile Phone Service (AMPS). As more customers flocked to wireless providers, networks were transitioned over to digital phones in order to save bandwidth. Some places still support AMPS but it has rapidly gone the way of the Dodo. But a few years back [Mark Atherton] got his hands on some old hardware, including a bag-phone and some test equipment, and set out to build a base station that can control AMPS handsets. In short, he’s creating his own analog cellphone tower. There’s a wealth of information on his page. The writeup comes out as a mix of protocol and electronic resources he scavenged across the net, as well as a work log serving as a testament to his successes and failures. He did his experiments in New Zealand, so if you’re thinking of undertaking this make sure to research your local radio regulations first.

[Thanks J]