Polyphony and monophony in instruments harpejji and the Chapman stick). Multiphonics can be used with many regular wind instruments to produce two or more notes at once, although this is considered an extended technique. Explicitly polyphonic wind instruments are relatively rare, but do exist. The standard harmonica can easily produce several notes at once. Multichambered ocarinas are manufactured in a number of varieties, including double, triple, and quadruple ocarinas, which use multiple chambers to extend the ocarina's otherwise limited range, but also enable the musician to play more than one note simultaneously. Harmonic ocarinas are specifically designed for polyphony, and in these instruments the range
Owned-and-operated television stations in the United States is now held by WNLO and the channel 17 frequency is now held by WBXZ-LP; WNED still holds the virtual channel 17 in the Buffalo market, but has not advertised it since the early 2000s). Similarly, CBS bought UHF stations WGTH-TV (channel 18) in Hartford and WOKY-TV (channel 19, later on channel 18) in Milwaukee in 1955, and changed their call letters to WHCT-TV and WXIX-TV, respectively. However, CBS' ratings were astonishingly low in those markets. In 1959, CBS decided to move its Hartford and Milwaukee affiliations to VHF stations WTIC-TV and WITI-TV (channel 6) respectively, and sold off what