Hello John.

The research at the time indicated the younger generation did not vibe with the WLS call signs, as it was identified as being too old. Z95 was more in line with B96 and they wanted to miminc Z100 in NYC. But the WYTZ call sign was too hard to recite in the arbitron ratings books. They were going to change call signs a few years after they moved from WLS-am but they realized they had too much invested. Ultimately they believed they could carve out separate successful identities between the AM & FM signals and call signs. As we know, both failed, until WLS-FM resurfaced years later.

Z