Article
I had this theory for quite some time that you should be able to listen to the Famicom’s audio broadcast on a standard FM radio receiver in the US because the frequencies match and the TV sound channel is modulated in FM just like the radio stations. So I decided to put my theory to the test by connecting my Famicom’s RF output to the antenna of an old radio cassette receiver, then tuning the dial to the right frequency to produce Famicom sound out of the radio speaker. So I tried that out and it worked!
You can try it out with a un-modded Famicom system, an FM radio receiver, and a single RCA cable. Just plug the RCA cable into the Famicom’s RF port and tune your radio into 95.75 MHz for Famicom CH1 and 101.75 MHz for Famicom CH2. To get better reception, wrap the RCA cable around the radio’s antenna or touch the RCA cable’s tip directly to the antenna.
This works because even if Japan uses the same TV system as the US (NTSC), their TV channel frequencies are different. US/World FM radio spectrum goes from 87.5 to 108 MHz , while JP FM radio goes from 76 to 90 MHz. The result is that all of the analog TV channels are in different places.
JP TV Channels 1 and 2 correspond to 91.25 and 97.25 MHz respectively, just above the JP FM radio band but right in the middle of the US FM radio band! A TV channel is 6 MHz wide, and by adding 4.5 to the video carriers you get the sound carriers, 95.75 and 101.75 MHz respectively, which are still in the middle of the US/World FM dial.
US Cable channels 95 and 96 use the exact same frequencies as JP channels 1 and 2 , which is a blessing for Famicom owners who don’t want to use an AV mod. In the US, these channels are seldom used because of the interference with FM radio broadcasts (even though a cable TV system is completely isolated in theory, you’ll always get some interference in real world usage).
This also explains why your Famicom might look like crap on your TV if you’re using the RF modulator and Channel 95. If there are strong radio broadcasts in your area in the vicinity of those frequencies, they’ll interfere with your Famicom’s video signal (and you’ll have nobody to complain to, since the Famicom is using an illegal frequency in the US radio spectrum). You could largely alleviate the problem by using thick coaxial cable between the Famicom’s RF out and your TV’s aerial socket, in order to keep those pesky talk shows from messing with your Japanese video games.
