were common in the late 1960s and early '70s, particularly on the FM band, but are rare today. An exceptional case was Indie 103.1 FM of Santa Monica and Newport Beach, California. Indie 103.1 broadcast radio programs in which famous musicians from the world of popular music host radio programs and choose the playlist. Indie 103.1 recently left the FM airwaves, but currently continues on the internet. Another commercial free-form radio station is KHUM, "radio without the rules", at 104.3 and 104.7 FM in Ferndale, California. KHUM has transmitted since 1996 and is the most popular station in Humboldt County, California. Internet radio and, to a lesser extent, college radio are sanctuaries of the free-form format (although even the latter has lost much of its independence as stations begin modeling corporate stations in their presentation). On Sirius XM satellite radio, the weekly Bob Dylan-hosted Theme Time Radio Hour featured a freeform format, as do several specialty programs on The Loft. The nationally syndicated Undercurrents, distributed by Native Voice One, follows a freeform format. Many terrestrial freeform stations are small and lack corporate backing, and therefore have relatively weak radio transmitters (especially around metropolitan areas where corporate radio signals dominate, but at the same time have enough of a population density to cover enough people to support such a station), a problem that has caused numerous broadcasters to transition to Internet radio, pirate radio or both. The full service format can be seen as a variant of the free-form format, though since most full-service stations are located in rural areas, country music, adult standards, classic hits (oldies or classic rock), and occasionally adult contemporary music tend to form the bulk of the music on a full-service station, and the vast majority of full-service stations focus primarily on mainstream, popular music (whereas freeform stations often put the emphasis on less widely known or more exotic selections). Adult hits/Jack FM The adult hits brand can be considered a "sequel" of sorts to the freeform format. Many of these stations play a wide variety of music ranging from many formats that includes, but is not limited to: Oldies/classic hits, classic rock, adult contemporary, Mainstream Top 40/Adult Top 40, etc. Most of the music played on these stations are from the years 1970–2020, although a few 1960s tracks may be sprinkled in. Unlike true freeform radio, there are no disc jockeys. The most notable adult