Isn’t WBCT’s 320kW the highest powered grandfathered FM?
In 2013, Doug Smith put together a list of superpower FMs. It's now available only via the Internet Archive. The original URL was
http://www.w9wi.com/articles/superfm.html - the site itself is now gone, and I don't know where Doug is these days. I saved the list, and here's an extract of the list showing stations with ERPs above 100 kw. (Note that there are multiple categories of superpower, but I don't want to complicate the discussion.)
The screenshot immediately below may be easier to read directly than the text copy-and-paste, but the screenshot isn't friendly to those who are visually impaired, so I've provided both. HAAT is in meters; ERP in watts. Fields were tab-delimited.
This information is from 2013, so some attributes such as call letters may have changed in the meantime.
Oddly, KRUZ is
not in the list, though clearly it is currently licensed for 105 kw.
KRUZ is not even the highest-powered station in California; KIOI San Francisco has 125 kw. Even then, KIOI needs boosters in the Diablo Valley, where, it is said, FM signals go to die.
Call Letters Frequency City HAAT ERP Class maximum ERP Height-limited ERP 60dBu contour Amount 60dBu exceeds maximum
KPFK 90.7 CA Los Angeles 863 110,000 50,000 930 103.15 51.15
KQED-FM 88.5 CA San Francisco 387 110,000 50,000 7,000 79.77 27.77
WBCT 93.7 MI Grand Rapids 238 320,000 50,000 20,000 78.69 26.69
KIOI 101.3 CA San Francisco 354 125,000 50,000 8,600 78.64 26.64
WTSS 102.5 NY Buffalo 355 110,000 50,000 8,600 77.42 25.42
WNCI 97.9 OH Columbus 171 175,000 50,000 38,000 66.36 14.36
WDCX-FM 99.5 NY Buffalo 195 110,000 50,000 29,500 64.24 12.24
WOMC 104.3 MI Detroit 110 190,000 50,000 50,000 58.49 6.49
WSLQ 99.1 VA Roanoke 607 150,000 100,000 97,000 96.36 4.36
KZZO 100.5 CA Sacramento 100 115,000 50,000 50,000 52.12 0.12
WMC-FM 99.7 TN Memphis 277 290,000 100,000 100,000 81.24 -10.76
KGOR 99.9 NE Omaha 375 110,000 100,000 100,500 78.89 -13.11
WMC-FM had 300 kw originally; there was a slight downgrade due to some adjustment or another.
Edit: Another omission in the list, which I definitely should caught: KHKI Des Moines, currently with 105 kw and 143m HAAT - originally was KDMI with 115 kw. It was one of the few Des Moines stations that I could receive at my southern Iowa location near the Missouri border, but it wasn't of much interest: preaching programs. The state of FM in that part of the world was pretty dismal from a teenager's point of view in the early 1970s.