There are a number of annual radio conferences running today. NAB of course is the large commercial conference and CMJ is usually considered the bigger of the college focal conferences: IBS, CBI etc. IBS of course is the oldest but it's ivy league roots have really kept it inside it's own social enclave and there is a strange long story to explain why.
The history of student broadcasting in Ivy League schools starts early. WBRU and WHCN founded IBS in February 1940. George Abraham a student at Brown interconnected half a dozen radios in his building so they could all hear his classical recordings. It went so well he expanded service to a dorm across the street, then the rest of the campus. Eventually 100 radios were tied to his "Brown Network" with 16,000 feet of cable. Programming began in earnest. The Brown University station WBRU was the first on air in 1940.
Harvard followed them in 1943 with WHCN graduating from their own carrier current system. You may nto recognize those calls because WHCN only used those calls until 1951 when they broke off from the campus newspaper and became WHRV. These two stations founded the first college network, IBS the Intercollegiate Broadcasting System.
IBS was founded by the intrepid engineer being WBRU George Abraham, and his cohort David Borst. they were still undergraduates at the time. By 1947 there were five members in the IBS: WDBS at Dartmouth, WHRV at Harvard, WXPN at U. Pennsylvania, WPRU at Princeton, and WYBC at Yale. WPRU at the time was broadcasting just through the universities electrical system. In 1956 they applied for a FM license but had to change calls because a ship at sea was using the WPRU calls.
In 1943 WVBR Cornell, WDCR Dartmouth, WPRU Princeton, and WYBC Yale split off from IBS and formed their own network called the Ivy Network. WXPN Pennsylvania joined in 1948. It's offices remained based at Yale in New Haven, CT. More here. At a conference in 1951 they met and accept ed a contract to allow Ivy stations to broadcast the nationally-heard "Philip Morris Play House." NBC was to install dedicated telephone lines to enable syndication. In 1953 the NBC tie was expanded with a contract to carry more programs. The Ford motor company sponsored a classical music program. More here. WKCR at Columbia University joined sometime in the 1950s.
What's most important to remember here is that these were all AM stations and were permitted to run advertising. It's only when they moved to the FM band they were restricted to non-commercial licenses that forbid advertising. IBS and The Ivy Network shared member stations. Some texts even have WBRU carrying programs via the Ivy Network after 1952, effectively merging the two splinter groups. I assumed originally that this marked the end of the Ivy Network but it did not. In 1960 a small group of stations from the Rural Radio Network began calling themselves "The Ivy Network." This had to create brand confusion. So I assumed that had to be after the end of the Ivy Network. That was wrong too.
In February of 1961 an issue of Billboard refers to IBS and the Ivy Network as the two largest college radio networks. The article was written by Jim Cameron of WLVR, the college radio station of Lehigh University. This was not a misinformed outsider. Clearly both IBS and Ivy were still operating in the early 1970s in some capacity. And it seems to be true. In 1966 the eight existing Ivy Network stations invited 11 more: Boston College, Colgate U. Middlebury College, M.I.T., N.Y.U., Lehigh, St. Lawrence, Union, and American University. Again many of these were still carrier current stations. One piece I read indicated that a slew of Boston area stations joined Ivy at the end: WTBU, WZBC, WBRS, WHRB, WTBS, WZLY and WBRU. I have some trouble crediting this as the network ceased to exist shortly thereafter. In 1969 the Network had a reporter Linda Sutter give a report by phone live from Woodstock. That was taped and survived to appear at a recent auction. More here.
I cant seem to find a firm date where the Network ended. But I think i know what happened. The growth in FM undermined their ability to sell advertising. A WYBC history spells it out "During the late 1970s and 1980s, WYBC fell into financial trouble due to declining student interest." Yale went through a rough patch in which 94.3 was LMA'd to COX radio, and their AM stick sold off outright. They had a resurgence in 1998 with 1340 a new license but they were the lynchpin for The Network. One record I found has Stan Federman, WXPN manager, named president o f the Ivy Network and the Network HQ relocating to U. Penn. So WYBC implodes, Ivy relocated around WXPN which was already moving to FM themselves. It fell apart gradually losing importance and being more fully absorbed into IBS.