To expand onwhat Kevin said:
560/WLIT (LIT Brothers department stores) & 560/WFI (Strawbridge & Clothier department stores) were share timers in the 20's & 30's. One would be on for an hour and a half and then the other would sign for an hour & a half while the other signed off. This would go on all day long. They would constantly get into fights as to who stayed on an extra few minutes beyond their designated sign off. This would continually trigger a complaint to the FRC (Federal Radio commission, before the FCC). The two were constantly at each other.
WLIT, owned by the LIT Brothers department stores later merged with WFI, owned by the Strawbridge & Clothier department store to form WFIL. The department store families and their respective companies initially underwrote and established early radio broadcasts to sell their wares.
Gimbel Brothers department store was another such entity that had a broadcast frequency 610/WIP. Strawbridge and Clothier, Gimbel Brothers and Lit Brothers were all across the street from each other on either side of Market St. and each had their hammock antennas on top of their respective flagship department stores in center city Philadelphia.
http://hylitradio.com/productlogo/litbrothers
John Wannamaker department stores also had a station on the air 1200/WOO. Many a day one would hear the famous organ at 13th & Market being played on the air. Most shopping traffic looking for radio's went to LIT's or Strawbridge's because Wannamaker's never sold radio's. Later Wannamaker would return the license to the FCC and sign WOO off for good.
Another such sharetimer in Philadelphia was 1340/WTEL & 1340/WHAT. Only in this case the transmitter for WTEL was located above the far end of Broad Street at 4140 Old York Rd in North Philadelphia and WHAT's transmitter was in the Wynnfield section of Philadelphia where it is today. One again each station would broadcast for and hour or and hour and a half and sign off and the other would sign on. It must have been a complete audience shift because of the geographic seperation of the transmitters.
By 1950 the FCC began to open up channels for daytime broadcasting only and WTEL completed the move to 860 as a daytimer in the early spring 1951 with 250 watts from 4140 Old York Rd. Philadelphia, by early Spring 1951. 860/WTEL would later relocate their transmitter to Norristown and increase power to 5,000 watts.
Hy Lit started his career and broadcast on 1340/WHAT in1954
http://hylitradio.com/productlogo/hylitwhat2 from the original studios
http://hylitradio.com/productlogo/WHATBuilding that William & Dolly Banks built in the Wynnefield section of Philadelphia at 3900 Conshohocken Ave, where the transmitter remains today. (publicity photo of Hy Lit at WHAT AM/FM
http://hylitradio.com/productlogo/hylit1340what
Dolly Banks Shapiro and her brother William A. Banks purchased WHAT Radio from the Philadelphia Public Ledger newspaper in 1944. The purchase price was $23,500.
By contrast Max Leon purchased WDAS, a full time station, albeit only 250 watts around 1950 for $500,000
Share timers were common place in the early day's of broadcasting.
WHAT History: The station came on the air in 1923 as WNAT. At that time, WNAT broadcast at 833 KHz, sharing their frequency with WGL, Philadelphia’s first radio station and WWAD. Two years later in 1925, WNAT shared time and their 1200 KHz frequency with WIAD and WWAD, all three were 100 watt Philadelphia stations. In 1928, WNAT, still at 100 watts, was sharing their 1040 KHz frequency with the more powerful WRAX, a 250-watt Philadelphia station. In 1929, it became WHAT Radio and the following year moved to 1310 (where it would stay for several years) sharing time with WFKD in Philadelphia. The next year, WFKD became WTEL. On March 29, 1941, WHAT moved to 1340, but so did WTEL. The early days of radio were quite different from today. Many stations shared frequencies, and Before 1950, WTEL and WHAT were share-timers at 1340 on the dial. Each station had about three or four hours on the air and then would sign off for the other station to broadcast. It was back and forth all day long in this manner. This continued until 1950 when WTEL (now know as WWDB) moved to 860 KHz.
WHAT-FM started frequency modulation broadcasting in the early 50’s. Shortly after that time, Broadcast Pioneers member Sid Mark started playing jazz on FM overnights. As the popularity grew, the Banks decided to broadcast jazz, 24 hours a day, the first in the nation. It would keep that format for 17 years until it went with a talk format (March 17, 1975) using the call letters, WWDB (We’re William and Dolly Banks). Again, the station made history as the first FM telephone talk station in the U.S.A.
Both stations (WHAT & WWDB) are known for innovation (under the Banks’ ownership). The paper said, "in 1945, WHAT became the first U.S. radio station to hire a full-time black announcer, the first to program a regular show featuring a black woman (Mary Dee) as hostess and the first station in the city to hire black newscasters. It also was the first in the nation to feature a black host of a daily talk show."
William Banks started as a time salesman for WELK Radio (now WDAS) in 1928. The next year, he moved over to WIP Radio Gimbel Brothers broadcasting). He started there in 1929.
Billy decided to buy his own radio station when Ben Gimbel who owned WIP called him into his office. Gimbel's complaint was that Billy was selling too much radio time. Ben Gimbel told Billy that Banks was making more in commission that Gimbel earned as General Manager. Billy got his commission reduced and Banks swore he would never let it happen again. The only way was to own a station.