Anyone who grew up in the CRT era of TVs remembers that you had to turn the channel to 3 before you turned on the VCR or game console. Otherwise, the picture would not work. Why was this so necessary?
Edit: woah this blew up while I wasn’t looking! Thanks for the replies!
In: Technology
Channels on old CRTVs that had TV *tuners* are basically different frequencies that you tune your TV to, like how you turn your radio to a specific frequency to pick up a channel you wanted to listen to.
Edit: it was channel 3 (or the selectable alternative to avoid interference) because the NES/VCR had to be talking in the same “language” (channel 3 frequency 60-66 MHz, channel 4 frequency 66-72 MHz, or channel 5 frequency 76-82 MHz depending on where you live and which had the least interference for you).
Back in that day we had no way of transmitting the image and sound from the game console or VCR directly to the TV like we do today with S-video, component, HDMI, Display port, etc. So the simple solution was to turn the image and sound into radio ~~waves~~ frequencies and transmit it to the TV like a TV station. To comply with Federal regulations this TV signal from the console would have to be very weak so that it wouldn’t interfere with any other signal. This means that the console could only transmit the signal a few millimeters to centimeters. To get around this limitation they used coaxial cable to carry the signal but you still had to tune the TV into the frequency the console/VCR was transmitting at.
This guy does a good job explaining that a NES and similar devices are actually mini TV transmitter stations. [~~https://youtu.be/8sQF_K9MqpA~~](https://youtu.be/8sQF_K9MqpA) [https://www.youtube.com/watch?v=8sQF_K9MqpA](https://www.youtube.com/watch?v=8sQF_K9MqpA) (I’m not sure what’s going on with URLs today, people are saying my link is broken but when I click on their links, I get the exact same URL that I posted…)
Edit: this really blew up. To clarify some things:
* I accidently put radio ***waves***, the NES doesn’t transmit (yes it’s a transmitter) radio waves, it transmits electric Radio Frequency (RF) to the RF modulator/adaptor that translates that signal into the frequency range used by the selected channel. (There’s probably something I don’t understand about this as I understand modulation is changing the frequency rate to transmit more and varied information u/maxwellwood did a great job expounding on this [here](https://www.reddit.com/r/explainlikeimfive/comments/nud63i/eli5_why_did_old_tvs_require_that_the_channel_be/h10vhzt?utm_source=share&utm_medium=web2x&context=3)).
* Technically speaking anything that transmits electric RF also inadvertently transmits radio waves in the form of electromagnetic RF radiation. This is mitigated. Blocked by what is known as shielding.
* Yes, I know about the two screw antenna connection. Technically, a coaxial cable is that two screw connection bundled into a single, shielded cable with a universal/standardized connector.
* Yes, you can transmit your game console’s frequency over the air to your TV with the appropriate Electric RF to electromagnetic RF amplifier. All electric RF produces radio waves as far as I’m aware whether on purpose or not. Doing this while remaining in the grey area of legality in most countries would get you a pretty crappy signal to the TV though at any distance you couldn’t just use the cable.
* All cables used to take audio/video (AV, A/V) from a device to a TV is a transmission of data regardless of electric verses electromagnetic.
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