A television transmission channel immediately adjacent to an existing channel. For example, channel 3 is adjacent to channels 2 and 4. There are three exceptions to what might otherwise be considered adjacent channels: there is a small gap between channels 4 and 5, there is a large gap between channels 6 and 7, and there is an enormous gap between channels 13 and 14. Adjacent channels figure into ATV in two ways. a) First, it is currently illegal to broadcast on adjacent channels in a single location. Some ATV proponents feel that augmentation channels might someday be allowed to be placed in adjacent channels. If half-size (3 MHz) or smaller augmentation channels are used, all current broadcasters could then be allowed an augmentation channel. Some proponents feel the use of a low-power digital augmentation channel will allow adjacent channels to be used without interference. b) Second, some ATV proposals require that the augmentation channel be adjacent to the transmission channel or require a larger than normal transmission channel, thus occupying a channel and one of its adjacent channels.