WBLM signed on the air on March 1, 1973 on 107.5 MHz. By day, it played Beautiful Music with free-form progressive rock airing from 6 p.m. to 6 a.m. The station was licensed to Lewiston, Maine and its antenna was located in Litchfield, Maine, also the site of the original studio, which was a double-wide mobile home. Later that year, WBLM became a full-time progressive rocker. The first rock songthe station played on the air was The Story in Your Eyes by the Moody Blues. Given that the transmitter site was some away from Portland, the station's signal was somewhat spotty in Portland and beyond. In 1979, it modified its format to mainstream album-oriented rock, after being challenged in the ratings by what at the time was a new 3,000-watt album rock station, 100.9 WLOB-FM, known as "FM 101" and currently WYNZ. In fact...Air personality John Clark from FM-101 defected to WBLM in late 1981. On December 6, 1989 it switched frequencies with 102.9 WTHT. 102.9 was previously beautiful music station WGAN-FM from its sign-on in February 1967 until 1985. Prior to 1966, 102.9 was WLOB-FM, but not related to today's AM 1310WLOB. The 107.5 frequency is now WFNK, ironically a direct competitor to WBLM with a classic rock/classic hits format. The two stations are often at the top of the Portland ratings list. WBLM has a colorful connection to rock acts Frank Zappa and Captain Beefheart. WBLM's nickname is "The Rock and Roll Blimp". The stations on air catchphrase is: "It's The Blimp Frank it's The Blimp!"; both refer to the Captain Beefheart track off the albumTrout Mask Replica "The Blimp", which is where the catchphrase comes from. It's The Blimp "Frank" is in reference to Frank Zappa as the portion of the song used for the catchphrase is a recording of a phone call made from Beefheart's recording session back to their record label owner Frank Zappa about their new song titled "The Blimp". The "Cosmic Muffin" astrological forecast, which was a daily report on WBLM for years also used as its theme song "Muffin Man" by Frank Zappa, specifically the vocal portion proclaiming "The man thought he was a man but he was a muffin." On August 30, 2013, a deal was announced in which Townsquare Media would acquire 53 stations from Cumulus Media, including WBLM, for $238 million. The deal is part of Cumulus' acquisition of Dial Global; Townsquare and Dial Global are both controlled by Oaktree Capital Management. The sale to Townsquare was completed on November 14, 2013.