Richard Fry wrote:
"The most common radiator height for Class A non-directional AM
broadcast stations operating at 50kW day and night is 195-degrees."

"Richard Harrison" responded (in part)
I won`t challenge that as I have conducted no survey. WJR Detroit is
shown on the broadcast allocations map book as an unlimited (day and
night) 50 kilowatt Class 1 station.
__________________

Your text is referenced to out-of-date versions of applicable FCC Rules.
The FCC adopted the metric standard over 15 years ago, and the
classification of AM broadcast stations no longer is defined as Class 1 to 4
but Classes A, B, C & D. The current versions of the applicable Rules are
contained in 47CFR Part 73, and for this topic are dated October 1, 2004.

Minimum radiator heights in meters for Class A, B and C AM broadcast
stations are shown in Figure 7 of 47CFR73.190. Radiator efficiency for
Class A stations (other than in Alaska) must be such as to produce a ground
wave of least 362 mV/m at 1km for 1kW of antenna input power. A 90° omni
radiator cannot do that.

RF