Yes, AM, from some of the links in the article. Probably for backwards compatibility: the video version could carry 5 MHz FM video with an AM audio channel. h

Yes, AM, from some of the links in the article. Probably for backwards compatibility: the video version could carry 5 MHz FM video with an AM audio channel. https://www.cryptomuseum.com/covert/opto/jo406/index.htm https://www.cryptomuseum.com/covert/opto/jo406/index.htm