ntsc

46 Articles

Time’s Almost Up For The FrankenFMs: The Impending Switchoff Of Analog TV

March 13, 2021 by 30 Comments

In a time when multi-channel digital TV is the norm it’s a surprise to find that a few low-power analog stations are still clinging on in some American cities. These are sometimes fill-in stations for weak signal areas, or more usually the so-called “FrankenFM” stations who transmit static images or digital patterns and derive income from their sound channel lying at the bottom end of the FM band to form unintended radio stations. Their days are numbered though, because the FCC is requiring that they be turned off by July 13th. There’s a way forward for the broadcasters to upgrade to low-power digital, but as you might expect they’re more interested in retaining the FrankenFM frequency from which they derive income.

The industry is represented by the LPTV coalition, who have requested permission to retain their FM frequency alongside their digital service. This has faced stiff opposition from other broadcasters, who see the very existence of the FrankenFM stations as a flagrant flouting of the rules that shouldn’t be rewarded. The FCC have yet to make a ruling, so there remains a slim chance that they may win a reprieve.

The sad tale of the few lingering analog TV stations in the USA is a last flickering ember of a once-huge industry that has been eclipsed without anyone but a few vintage technology geeks noticing, such has been the success of digital broadcasting. But analog TV is a fascinating and surprisingly intricate system whose passing however faint is worth marking.

Header: Tiia Monto, CC BY-SA 3.0.

The Last Few Analogue TV Stations In North America

January 29, 2021 by 40 Comments

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.

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Grey Gear: French TV Encryption, 1980s Style

June 25, 2020 by 38 Comments

Who among us didn’t spend some portion of their youth trying in vain to watch a scrambled premium cable TV channel or two? It’s a wonder we didn’t blow out our cones and rods watching those weird colors and wavy lines dance across the screen like a fever dream.

In the early days of national premium television in America, anyone who’d forked over the cash and erected a six-foot satellite dish in the backyard could tune in channels like HBO, Showtime, and the first 24-hour news network, CNN. Fed up with freeloaders, these channels banded together to encrypt their transmissions and force people to buy expensive de-scrambling boxes. On top of that, subscribers had to pay a monthly pittance to keep the de-scrambler working. Continue reading “Grey Gear: French TV Encryption, 1980s Style” →

Run Your Favorite 8-bit Games On An ESP32

June 9, 2020 by 20 Comments

Here at Hackaday HQ we’re no strangers to vintage game emulation. New versions of old consoles and arcade cabinets frequently make excellent fodder for clever hacks to cram as much functionality as possible into tiny modern microcontrollers. We’ve covered [rossumur]’s hacks before, but the ESP_8-bit is a milestone in comprehensive capability. This time, he’s topped himself.

There isn’t much the ESP 8-bit won’t do. It can emulate three popular consoles, complete with ROM selection menus (with menu bloops). Don’t worry about building a controller, just connect any old (HID compliant) Bluetooth Classic keyboard or WiiMote you have at hand. Or if that doesn’t do it, a selection of IR devices ranging from joysticks from the Atari Flashback 4 to Apple TV remotes are compatible. Connect analog audio and composite video and the device is ready to go.

The system provides this impressive capability with an absolute minimum of components. Often a schematic is too complex to fit into a short post, but we’ll reproduce this one here to give you a sense for what we’re talking about. Come back when you’ve refreshed your Art of Electronics and have a complete understanding of the hardware at work. We never cease to be amazed at the amount of capability available in modern “hobbyist” components. With such a short BOM this thing can be put together by anyone with an ESP-32-anything.

There’s one more hack worth noting; the clever way [rossumur] gets full color NTSC composite video from a very busy microcontroller. They note that NTSC can be finicky and requires an extremely stable high speed reference clock as a foundation. [rossumur] discovered that the ESP-32 includes a PLL designed for audio work (the “APLL”) which conveniently supports fractional components, allowing it to be trimmed to within an inch of the desired frequency. The full description is included in the GitHub page for the project and includes detailed background of various efforts to get color NTSC video (including the names of a couple hackers you might recognize from these pages).

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This Commodore 16 Is An NTSC One… No, Wait, It’s A PAL One!

June 1, 2019 by 7 Comments

We’re used to our computers being powerful enough in both peripheral and processing terms to be almost infinitely configurable under the control of software, but there was a time when that was not the case. The 8-bit generation of home computers were working towards the limits of their capability just to place an image on a TV screen, and every component would have been set up to do just the job it was intended for. Thus when different countries had different TV standards such as the mostly-European PAL and the mostly-American NTSC, there would have been different models of the same machine for each market. The Commodore 16 was just such a machine, and [Adrian Black] has modified his NTSC model with a custom ROM, an Arduino and an Si5351 clock generator to be switchable between the two.

The differences between a PAL and NTSC C16 are two-fold. The clock for the video chip is of a different frequency, and the ROM contents differ too. [Adrian]’s machine therefore has a larger ROM containing both versions which are switchable via one of the upper address lines. A couple of tracks cut in the crystal oscillator circuit allow him to inject a new clock from the Si5351 module, and and Arduino controls everything. The appropriate ROM and clock are selected via a very simple interface, the reset button is captured and while a short press still resets the computer a long one switches the mode.

Despite having its principal engineer, [Bil Herd] as a colleague here at Hackaday, it’s sad that we don’t see as many Commodore 16s as we should. A recent feature showed a 64k C16, but didn’t make it into a C64.

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Vintage Monoscope Tubes Generate Classic TV Test Patterns Once Again

May 26, 2019 by 16 Comments

Night creatures and insomniacs of a bygone era may fondly recall a TV test pattern appearing once [Jack Parr] or [Steve Allen] had had their say and the local TV station’s regular broadcast day had concluded. It was affectionately known as the Indian Head test pattern, for the stylized Native American, resplendent in a feathered headdress, that featured prominently in the graphic.

Unknown to most viewers was exactly how that test pattern and others like it were generated. But thanks to [Rich “The Lab Guy” Diehl] and his monoscope restoration project, we can all share in the retro details. It turns out that while some test patterns were merely a studio camera trained on a printed card, most were generated by a special tube called a monoscope. It functioned in basically the same manner as a studio camera, but rather than scanning the incident light of a scene with an electron beam, the image was permanently etched into a thin aluminum plate. [Rich] laid hands on two vintage monoscope tubes, one containing the Indian Head test pattern, and set about building a device to use them. “The Chief” can hold either tube in a Faraday cage of thin, flexible PCB material and 3D-printed parts, with supporting electronics like the power supply and video amplifiers in an aluminum chassis below.

It’s a nice piece of work and a great lesson in how it used to be done, and the lithophane of the Indian head is a nice touch. Hats off to [The Lab Guy] for build quality and great documentation, including a detailed video series that starts with the video below. If you need a little more background on how video came to be, [Philo Farnsworth]’s story is a good place to start.

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Video Mangler For All Your Video Mangling Needs

April 22, 2019 by 8 Comments

Back in the ’70s and ’80s, before we had computers that could do this sort of thing, there were fully analog video effects. These effects could posterize or invert the colors of a video signal, but for the best example of what these machines could do just go find some old music videos from Top of The Pops or Beat Club. Stuff gets weird, man. Unfortunately, all those analog broadcasting studios ended up in storage a few years ago, so if you want some sweet analog effects, you’re going to have to build your own. That’s exactly what [Julien]’s Video Mangler does. It rips up NTSC and PAL signals, does some weird crazy effects, and spits it right back out.

The inspiration for this build comes from an old ’80s magazine project called the ‘video palette’ that had a few circuits that blurred the image, turned everything negative, and could, if you were clever enough, become the basis for a chroma key. You can have a lot of fun when you split a video signal into its component parts, but for more lo-finess [Julien] is adding a microcontroller and a 12-bit DAC to generate signals that can be mixed in with the video signals. Yes, all of this can still be made now, even though analog TV died a decade ago.

The current status of this project is a big ‘ol board with lots of obscure chips, and as with everything that can be described as circuit bending, there’s going to be a big panel with lots of dials and switches, probably stuffed into a laser-cut enclosure. There’s a mic input for blurring the TV with audio, and enough video effects to make any grizzled broadcast engineer happy.