KXTC was a jazz station (and a pretty good one) back in the early-mid 1970s. They had studios somewhere in the Westward Ho, but I understand they were pretty bleak - nothing fancy. It would not be difficult to hoist an FM antenna on the old rig on top of the building.
Now that I think about it, 92.3 may have had an auxiliary xmtr up there when the Beer Baron (Fred Weber, for those new to the area) owned Power 92 and KFYI. But I may be wrong about that. I do know our engineers had to occasionally go into the upper reaches of the Ho to do some sort of work, but that may have been for our microwave repeaters.
For those interested in history, KPHO radio was on 910, and the towers are located near I-17 and Glendale Ave. KPHO eventually became KJJJ, a successful country station for many years, and then in 1986 was flipped to KFYI.
KXTC, as mentioned before, was a commercial jazz station that flipped to disco (DISCO 92...ECSTASY RADIO!!!) in the late 1970s. Then I think they went country to complement KJJJ AM before being flipped to 92 Fire FM when the Beer Baron flew into town.