Dave P. wrote:
"Is there any place I can find polar graphs of commercial broadcast
stations?"

I have an old book, "Map Book, 540 kc to 1600 kc" published by
"Cleveland Insritute of Radio Electronics". In it, WABC is 50 KW
non-directional day and night. It shares 770 kc with KOB Albuquerque, 50
KW day and 25 KW night. Also, KUOM Minneapolis and WCAL Nortjhfield are
both 5 KW and share the frequency on some schedule between themselves.
WNEW St. Louis is on the frequency daytimes only, as is KWA Seattle, 1
KW. XEHB in San Francisco de Oro, Mexico is a 500 watt daytimer on the
frequency, as are XELM, 150 watts at Lagos de Morens and XEDI at
Queretaro, 1 KW. There is also CMDC, 1 KW at night when it could trouble
you in Holquin, Cuba. So, at night there is possible same-channel
interderence from New Mexico and Cuba. On 760 kc, you have WJR in
Detroit 50 KW non-directional at night and on 780 kc, you have WBBM in
Chicago 50 KW nondirectional at night. These non-directional 50KW
adjacent channel stations may exercise your AVC.

On 880 kc, WCBS has no same-channel night rivals but WLS (World`s
Largest Store, Sears in Chicago) on 890 kc, onetime home of "The
National Barn Dance", could work your AVC. Also, WWL in New Orleans
occupies 870 kc with 50 KW.
Good preselection will rid you of adjacent channel interference. I lived
in Portugal for years and listened to WCBS nightly. I would rock my
tuning from 880 to 870 for WWL during fades for my version of frequency
diversity. Both stations carried the same CBS programs. My antenna was a
Beverage aimed at New York. The receiver was a Hammarlund SP-600 which
had plenty of preselection to avoid adjacent channels. Ed Murrow came in
very well.

Best regards, Richard Harrison, KB5WZI