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Hackaday Links: December 11, 2022

“They paved paradise and put up a parking lot.” That might be stretching things a bit, especially when the “paradise” in question is in New Jersey, but there’s a move afoot to redevelop the site of the original “Big Bang Antenna” that has some people pretty upset. Known simply as “The Horn Antenna” since it was built by Bell Labs in 1959 atop a hill in Holmdel, New Jersey, the antenna was originally designed to study long-distance microwave communications. But in 1964, Bell Labs researchers Arno Penzias and Robert Wilson accidentally discovered the microwave remnants of the Big Bang, the cosmic background radiation, using the antenna, earning it a place in scientific history. So far, the only action taken by the township committee has been to authorize a study to look into whether the site should be redeveloped. But the fact that the site is one of the highest points in Monmouth County with sweeping views of Manhattan has some people wondering what’s really on tap for the site. A petition to save the antenna currently has about 3,400 signatures, so you might want to check that out — after all, you don’t know what you’ve got ’til it’s gone.

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Hackaday Links: November 20, 2022

Lots of space news this week, with the big story being that Artemis I finally blasted off for its trip to the Moon. It was a spectacular night launch, with the SLS sending the crew-rated but vacant — well, mostly vacant — Orion spacecraft on a week-ish long trip to the Moon, before spending a couple of weeks testing out a distant retrograde orbit. The mission is already returning some stunning images, and the main mission goal is to check out the Orion spacecraft and everything needed for a crewed Artemis II lunar flyby sometime in 2024. If that goes well, Artemis III will head up in 2025 with a crew of four to put the first bootprints on the Moon in over 50 years.

Of course, like the Apollo missions before it, a big part of the crewed landings of the Artemis program will likely be the collection and return of more lunar rock and soil samples. But NASA likes to hedge its bets, which is perhaps why they’ve announced an agreement to purchase lunar regolith samples from the first private company to send a lander to the Moon. The Japanese start-up behind this effort is called ispace, and they’ve been issued a license by the Japanese government to transfer samples collected by its HAKUTO-R lander to NASA. Or rather, samples collected on the lander — the contract is for NASA to take possession of whatever regolith accumulates on the HAKUTO-R’s landing pads. And it’s not like ispace is going to return the samples — the lander isn’t designed to ever leave the lunar surface. The whole thing is symbolic of the future of space commerce, which is probably why NASA is only paying $5,000 for the dirt.

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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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Advertise Your Conference Schedule Via SSID

Whether it’s been a Python script running on a Linux box or an ESP8266, abusing using WiFi SSIDs to convey messages is hardly a new trick. But for DerbyCon 2019, [vgrsec] wanted to do put together something a little unique. Dare we say, even useful. Rather than broadcast out SSID obscenities or memes, this Raspberry Pi created fake WiFi networks that told everyone what talks were coming up.

The concept here is fairly simple: there’s a text file in /boot that contains the truncated names of all the talks and workshops in the schedule, one per line, and each line starts with the time that particular event is scheduled for. The script that [vgrsec] wrote opens this text file, searches for the lines beginning with the current time, and generates the appropriate SSIDs. With the number of tracks being run at DerbyCon, that meant there could be as many as five SSIDs generated at once.

Now in theory that would be enough to pull off this particular hack, but there’s a problem. The lack of an RTC on the Raspberry Pi means it can’t keep time very well, and the fact that the WiFi adapter would be busy pumping out SSIDs meant the chances of it being able to connect to the Internet and pull down the current time over NTP weren’t very good.

As the system was worthless without a reliable way of keeping time, [vgrsec] added an Adafruit PiRTC module to the mix. Once the time has been synchronized, the system could then run untethered via a USB battery bank. We might have put it into an enclosure so it looks a little less suspect, but then again, there were certainly far more unusual devices than this to be seen at DerbyCon.

Of course, if you’re OK with just dumping the entire schedule out at once and letting the user sift through the mountain of bogus SSIDs themselves, that’s even easier to accomplish.

A Walk-In Broadcast Transmitter

[Mr. Carlson] likes electronics gear. Mostly old gear. The grayer the case, the greener the phosphors, and the more hammertone, the better. That’s why we’re not surprised to see him with a mammoth AM radio station transmitter in his shop. That it’s a transmitter that you can walk into while it’s energized was a bit of a surprise, though.

As radio station transmitters go, [Mr. Carlson]’s Gates BC-250-GY broadcast transmitter is actually pretty small, especially for 1940s-vintage gear. It has a 250 watt output and was used as a nighttime transmitter; AM stations are typically required to operate at reduced power when the ionosphere is favorable for skip on the medium frequency bands. Stations often use separate day and night transmitters rather than just dialing back the daytime flamethrower; this allows plenty of time for maintenance with no interruptions to programming.

If you enjoy old broadcast gear, the tour of this transmitter, which has been rebuilt for use in the ham bands, will be a real treat. Feast your eyes on those lovely old bakelite knobs and the Simpson and Westinghouse meters, and picture a broadcast engineer in white short sleeves and skinny tie making notations on a clipboard. The transmitter is just as lovely on the inside — once the plate power supply is shut down, of course, lest [Mr. Carlson] quickly become [the former┬álate Mr. Carlson] upon stepping inside. Honestly, there aren’t that many components inside, but what’s there is big – huge transformer, giant potato slicer variable caps, wirewound resistors the size of paper towel tubes, and five enormous, glowing vacuum tubes.

It’s a pretty neat bit of broadcasting history, and it’s a treat to see it so lovingly restored. [Mr. Carlson] teases us with other, yet larger daytime transmitters he has yet to restore, and we can’t wait for that tour. Until then, perhaps we can just review [Mr. Crosley]’s giant Cincinnati transmitter from the 1920s and wait patiently.

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Turning Television Into A Simple Tapestry

Teleknitting, the brainchild of Moscow artist [vtol], is an interesting project. On one hand, it doesn’t knit anything that is useful in a traditional sense, but on the other, it attempts the complex task of deconstructing broadcasted media into a simpler form of information transmission.

Teleknitting’s three main components are the processing and display block — made up of the antenna, Android tablet, and speaker — the dyeing machine with its ink, sponges, actuators, and Arduino Uno, and the rotating platform for the sacrificial object. A program running on the tablet analyzes the received signal and — as displayed on its screen — gradually halves the number of pixels in the image until there is only one left with a basic representation of the picture’s colour. From there, thread passes over five sponges which dye it the appropriate colour, with an armature that responds to the broadcast’s volume directing where the thread will bind the object.

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Transmitting Analog TV, Digitally

If you want to really understand a technology, and if you’re like us, you’ll need to re-build it yourself. It’s one thing to say that you understand (analog) broadcast TV by reading up on Wikipedia, or even by looking at scope traces. But when you’ve written a flow graph that successfully transmits a test image to a normal TV using just a software-defined radio, you can pretty easily say that you’ve mastered the topic.

9944491474271463115_thumbnail[Marble] wrote his flow for PAL, but it should be fairly easy to modify it to work with NTSC if you’re living in the US or Japan. Sending black and white is “easy” but to transmit a full color image, you’ll need to read up on color spaces. Check out [marble]’s project log.

Hackaday has another hacker who’s interested in broadcasting to dinosaur TVs: [CNLohr]. Check out his virtuoso builds for the ATtiny and for the ESP8266.

(Yes, the headline image is one of his earlier trials with black and white from Wikipedia — we just like the look.)