Analogue TV is something that most of us consider to have been consigned to the history books about a decade ago depending on where in the world we are, as stations made the transition to much more power and frequency efficient digital multiplexes. However some of them still cling on for North American viewers, and [Antenna Man] took a trip to Upstate New York in search of some of them before their final switch-off date later this year.
What he reveals can be seen in the video below the break, an odd world of a few relatively low-power analogue TV stations still serving tiny audiences, as well as stations that only exist because their sound carrier can be picked up at the bottom of the FM dial. These stations transmit patterns or static photographs, with their income derived from the sound channel’s position as an FM radio station. While his journey is an entertaining glimpse into snowy-picture nostalgia it does also touch on some other aspects of the aftermath of analogue TV boradcasting. The so-called “FrankenFM” stations sound much quieter, we’re guessing because of the lower sound carrier deviation of the CCIR System M TV spec compared to regular FM radio. And we’re told that there are more stations remaining in Canada, so get out there if you still want to see an analogue picture before they’re gone forever. Where this is being written the switch to DVB was completed in 2013, and it’s still a source of regret that we didn’t stay up to see the final closedown.
Does your country still have an analogue TV service? Tell us in the comments.
Those little pocket TVs were quite the cool gadget back in the ’80s and ’90s, but today they’re pretty much useless at least for their intended purpose of watching analog television. (If someone is out there making tiny digital-to-analog converter boxes for these things, please let us know.)
Our favorite part of this project is the way that [technichenews] leveraged what is arguably the most useless part of the TV — the antenna — into the star. Their plan is to use the camera to peer into small engines, so by mounting it on the end of the antenna, it will become a telescoping, ball-jointed, all-seeing eye. You can inspect the build video after the break.
With the Raspberry Pi and a digital modulator, he’s got the only house on the block that’s wired to show The Simpsons all day. He has absolutely no control over which episode plays next, he can’t pause it, and its in presented in standard definition (a nightmare for anyone who grew up in the Netflix era) but a familiar viewing experience for the rest of us.
The key to this project is the Channel Plus Model 3025 modulator. It takes the feed from the antenna and mixes in two composite video sources on user-defined channels. All [probnot] had to do was find a channel that wouldn’t interfere with any of the over-the-air stations. The modulator has been spliced into the house’s coax wiring, so any TV connected to the wall can get in on the action. There’s no special setup required: when he wants to watch The Simpsons he just tunes the nearest TV to the appropriate channel.
Providing the video for the modulator is a Raspberry Pi, specifically, the original model that featured composite video output. While the first generation Pi is a bit long in the tooth these days, playing standard definition video is certainly within its capabilities. With a USB flash drive filled with a few hundred episodes and a bit of scripting it’s able to deliver a never-ending stream direct from Springfield. There’s still that second channel available on the modulator as well, which we’re thinking could be perfect for Seinfeld or maybe The X-Files.
Do you still have an old analog CRT television lying around? With the advent of digital signals, analog TV´s are going to the dumpster or the recycling center. But you can still put them to good use, just as [GreatScott!] did, by converting the TV into a crude oscilloscope.
The trick is to take control of the two deflection coils that move the electron beam inside the CRT in the horizontal and vertical directions. The video describes in detail the process of identifying the coils and using an Arduino nano in combination with a DAC to amplify the input signal in order to get the waveform in the TV screen. Step by step explanations and great editing make this project delightful to watch.
Even if you do not follow [GreatScott!]´s steps to build a simple oscilloscope, don´t throw away that vintage TV!, it is a great source of analog parts. The flyback transformer can be used to make a high voltage power supply, and you also get some nice high voltage capacitors (both electrolytic and mylar ones), the horizontal output transistor which is a high voltage one, ferrite transformers, magnet wire, plus a lot of other small parts. Other uses for old TV sets that you may want to try is to convert your TV into a gaming console, or an audio synthesizer controlled by drawing with a light-sensitive pen on a CRT television.
Bees are a crucial part of the ecosystem – without bees to act as pollinators, many plant species wouldn’t be able to reproduce at all! It’s unfortunate then that bees are struggling to survive in many parts of the world. However, [Louise Cosgrove] is doing her part – building homes for bees in old television sets.
The project started when Louise’s son-in-law left 100 (!) analog TVs at her home, having already recycled the picture tubes. That sounds kind of impolite to us, but we’ll give them the benefit of the doubt and assume they had some sort of agreement. [Louise] realised the empty television cases had plenty of ventilation and would make ideal homes for bees. By filling the empty boxes with natural materials like wood, bamboo and bark, it creates nesting places that the bees can use to lay their eggs.
Modern monitors with an HDMI input connect right up to the Pi. Before HDMI came VGA, but the Pi doesn’t do that natively. One solution is to use a composite-to-VGA converter and pull the composite signal out of the audio jack. Lacking the right 4-pole audio cable, [TPAI] soldered some RCA plugs directly onto the Pi, and plugged that into the converter. On a yet-older monitor, he faced a SCART adapter. If you’re European, you’ll know these — it’s just composite video with a different connector. Good thing he had a composite video signal already on hand.
The pièce de resistance, though, was attaching the Pi to his 1980 Vega TV set. It only had an antenna-in connector, so he needed an RF modulator. With a (presumably) infinite supply of junk VCRs on hand, he pulled an upconverter out of the pile, and got the Pi working with the snazzy retro TV.
Ever wonder why analog TV in North America is so weird from a technical standpoint? [standupmaths] did, so he did a little poking into the history of the universally hated NTSC standard for color television and the result is not only an explanation for how American TV standards came to be, but also a lesson in how engineers sometimes have to make inelegant design compromises.
Before we get into a huge NTSC versus PAL fracas in the comments, as a resident of the US we’ll stipulate that our analog color television standards were lousy. But as [standupmaths] explores in some depth, there’s a method to the madness. His chief gripe centers around the National Television System Committee’s decision to use a frame rate of 29.97 fps rather than the more sensible (for the 60 Hz AC power grid) 30 fps. We’ll leave the details to the video below, but suffice it to say that like many design decisions, this one had to do with keeping multiple constituencies happy. Or at least equally miserable. In the end [standupmaths] makes it easy to see why the least worst decision was to derate the refresh speed slightly from 30 fps.
Given the constraints they were working with, that fact that NTSC works as well as it does is pretty impressive, and quite an epic hack. And apparently inspiring, too; we’ve seen quite a few analog TV posts here lately, like using an SDR to transit PAL signals or NTSC from a microcontroller.