I double checked at the FCC db...KMIC is a DA-N......(U2??? Bono??

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The "U" designators are used by the World Radio TV Handbook, as well as AM DX clubs and listeners. They show what the various directional parameters are; powers are listed separately.
U1--Nondirectional antenna day and night
U2--Nondirectional antenna daytime, directional at night
U3--Directional antenna, same pattern, day and night
U4--Directional antenna, different patterns, day and night
U5--Directional antenna daytime, nondirectional at night
U6--Nondirectional antenna daytime, directional antenna, same pattern during critical hours and night
U7--Directional antenna, different patterns for day, critical hours, and night
U8--Nondirectional antenna daytime, directional antenna, different patterns for critical hours and night
U9--Directional antenna, different patterns for day and night, but nondirectional during critical hours.
U10--Nondirectional antenna day and night, but directional during critical hours only.
U11--Directional antenna, different patterns for day and critical hours, but nondirectional at night.
I also see listings of U12 and U13 but am not sure what these are...the WRTH does not give an explanation. Checking against Radio-Locator you find that those stations have critical hours/night power/pattern changes, but seem to fit into one of the other categories...so there is some additional parameter I'm not aware of...would have to plow into the FCC antenna tech data for those stations. One guess is changes in electrical height of nondirectional antennas involved.
There are also "D" designators for daytimers:
D1--Nondirectional antenna
D2--Nondirectional antenna day, directional antenna during critical hours
D3--Directional antenna
D4--Directional antenna, different patterns for day and critical hours
D5--Directional antenna day, nondirectional during critical hours
Obsolete now, but there were also "L" designators for "limited time" stations...these were essentially daytimers operating on the old clear channel frequencies...if the dominant fulltime station was to the east, the limited time station could sign on at the dominant stations sunrise time...and if the dominant station was to the west, the limited time station didn't have to sign off until sunset for the dominant station. Examples from the past: KCTA in Corpus Christi could sign on at the WBZ sunrise time in Boston...and the old WJJD in Chicago could stay on the air until sunset over KSL in Salt Lake City.
The old "L" designators were:
L1--Nondirectional antenna
L3--Directional antenna
Not aware of any other "L" designators for critical hours, etc...probably never used.