Raspberry Pi Broadcasts UHF Channels to CRT TVs

News
By Ash Hill
published

Share your screen or send videos to an old television over UHF.

Raspberry Pi UHF Broadcasting
(Image credit: devicemodder2 on Reddit)

It's not quite the same as running your own TV station and broadcasting episodes of Conan the Librarian to everyone in town, but this Raspberry Pi project is the next best thing. If you’ve got an old CRT TV lying around, you could be transmitting video to it over UHF using Redditor Devicemodder2’s CRT TV project. It’s built with a Raspberry Pi Zero and enables compatible CRT TVs within range to tune in to a predetermined channel for wireless video streaming.

The system relies on a Micro UHF Analog TV transmitter chip that's available on Ali Express for $15. This transmitter is connected to the composite video output on the back of the Pi Zero. 

Raspberry Pi UHF Broadcasting

(Image credit: devicemodder2 on Reddit)

In the image above, the yellow wire is signal, the orange is 5V power and the blue is ground. If you haven’t used a Pi Zero for composite video output before, check out this article from MagPi, the official Raspberry Pi magazine, for a detailed look at how it works on Raspberry Pi Zero. 

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Raspberry Pi
(Image credit: Devicemodder2)

According to Devicemodder2, RF-only TV sets within 100 feet can tune into the Raspberry Pi video feed. In this setup, the system transmits video output on channel 29. Devicemodder2 also clarified that the transmitter used in this project is configured only for PAL audio but the signal fed through it is NTSC. As such, there is no audio output, only a video feed.

Devicemodder2 created this project for the purpose of testing old CRT TVs they might want to buy from thrift stores or local sellers on Craig's List. With a UPS Lite V1.2 UPS Power HAT with battery and the transmitter both attached to the Pi Zero, they are able to make sure any TV is in working order, without plugging the Pi into either power or the television itself. 

The developer also told us that they use the Pi Zero to show still photo galleries on their CRT TVs over UHF. We're not sure what kind of frame rates you'd get for video playback or gaming.

Check out the original thread shared to Reddit for a closer look at this clever Raspberry Pi CRT TV broadcaster and tester.

Ash Hill
Ash Hill
Freelance News and Features Writer

Ash Hill is a Freelance News and Features Writer with a wealth of experience in the hobby electronics, 3D printing and PCs. She manages the Pi projects of the month and much of our daily Raspberry Pi reporting while also finding the best coupons and deals on all tech.

5 Comments Comment from the forums
  • Alvar "Miles" Udell
    So now you can re-create that iconic room from The Matrix III for your Tecchie Cave!

    Reply
  • KhristosEuangelion
    If in the US: Just remember UHF and VHF channels are in licensed frequency ranges... i.e. you can be fined for transmitting on a licensed fx without either licensed equipment, station, or operator depending on the frequency.
    Pretty sure that cheap transmitter hasn't been approved for most regulated countries...
    Reply
  • MisterZ
    Why only CRT TVs? Surely this would also work on older flat screens that have analog tuners.
    Reply
  • TheOldNet
    I did this about a year and a half ago using the same hardware. I wrote a webservice/app that lets you use your phone like a TV remote, where changing channels loads up different playlists. https://github.com/ssshake/pi-uhf-tv-station
    Reply
  • Dav_Daddy
    KhristosEuangelion said:
    If in the US: Just remember UHF and VHF channels are in licensed frequency ranges... i.e. you can be fined for transmitting on a licensed fx without either licensed equipment, station, or operator depending on the frequency.
    Pretty sure that cheap transmitter hasn't been approved for most regulated countries...

    As long as your transmitting power is not more than 4W you're in the clear. I don't see pulling 4W off of any pin on a Pi for more than a few seconds so as long as you don't use an external power source you should in the clear.
    Reply