I know that RF stands for radio frequency but what chip in the Atari handles the video output and does anybody know if something similar would work on a modern tv?

  • 3
    No, as modern TV no longer use NTSC over RF. Regarding the chips you may want to read up the very basics, like present on Wikipedia or more detailed sites. This would as well help to narrow the question down to an answerable sujet.
    – Raffzahn
    Commented Sep 11, 2022 at 23:17
  • 1
    Which Atari do you mean? -- Anyway, if you open its case, you will most probably find a silver block in it. It houses an RF sender built from cheap discrete components, no chip (as interpreted as silicon chip with multiple transistors) is involved. Do you mean something like this? Commented Sep 12, 2022 at 6:27
  • @thebusybee like what? Commented Sep 12, 2022 at 10:57
  • @OmarL Like "what chip", I interpret this as a synonym to "complex circuit". Commented Sep 12, 2022 at 12:21
  • 3
    There is, unfortunately, no "the Atari". There is a "the C64", however ;)
    – tofro
    Commented Sep 12, 2022 at 13:11

2 Answers 2


Devices of this era were designed to interface with common TV sets of the day. These used (mostly) one of two systems, NTSC (North America) and PAL (Europe and much of the rest of the world). These systems were for the VIDEO format but TV sets of the time rarely had direct video inputs. The only input on most TVs was "antenna" or RF input from an antenna or cable.

Often there were two screw terminals for a 300 Ohm twin-lead connection that was common. Later TVs added a coax connector that was used with cable TV converter boxes and later VCRs.

So the problem was how to get the video generated by a game console onto the screen of a TV. The answer was what is called an RF MODULATOR. These could be internal to the unit in which case there was either a coax output or a twin-lead output that could be connected to the TV. Other manufacturers chose to leave the RF modulator out of the unit and supplied or required an external RF modulator device. This took an input from the game console and converted it to RF usually on TV channel 3 or 4 whichever was not used by a local TV station.

As far as Atari goes, it's not clear which exact console or device you are talking about and they produced many different ones over the years and as I recall they used both internal and external RF modulators as well as later models that offered higher quality RGB outputs to get around the limitations of NTSC/PAL for those using their devices with dedicated computer monitors which had become common a few years after these devices were introduced.

Today, however, RF modulators have all but disappeared. The main reason is that HDMI is ubiquitous on TV sets of all sizes and that is very easy to add to any video-producing device.

  • 2
    +1 for a good explanation. But I disagree with The main reason is that HDMI is ubiquitous on TV sets of all sizes and that is very easy to add to any video-producing device. I think the main reason devices no longer use RF modulators is the switch to digital TV in 2009. Which means that (nominally) all TVs produced since 2009 do not even have an analog tuner compatible with an old-style RF modulator. A digital broadcast signal is far more complex to generate than an NTSC on analog 3 or 4, aside from any licensing issues (FCC) that may be involved. Commented Sep 12, 2022 at 15:48
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    @manassehkatz-Moving2Codidact Agree. It was not the HDMI input that was added, but the analogue input that was removed from TV sets that killed the RF modulator (and it's unearthly picture quality, ofc)
    – tofro
    Commented Sep 13, 2022 at 13:15

Old home computers made use of an off-the shelf RF modulator component.

Picture Sonnett72

These were ready-made analog boards (one prominent manufacturer was Astec, as in the picture) that converted Composite Video into an RF signal suitable for the home-TV's RCA input.

Because most modern TVs no longer have analogue input, such an approach wouldn't work today.

  • Love those old analog layouts. Are there traces on the bottom of the board or is it just component wires soldered together?
    – Jon Custer
    Commented Sep 12, 2022 at 14:33
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    @JonCuster ‒ There are traces at the bottom. It's from the 80s, not from the 50s ;-) Commented Sep 12, 2022 at 16:18
  • @MichaelGraf - hey, some ham folks still make things the tried and true fashion!
    – Jon Custer
    Commented Sep 12, 2022 at 16:32

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