Steve Green NEPA: That is not a surprise. KTRH sends most of its 50 kilowatts straight into the Gulf to protect KCMC in Texarkana. At night, you lose KTRH around Willis to the north, around 50 miles give or take. On the other hand, KTRH is basically a local signal in Corpus Christi to the southwest. Last time I went to New Orleans, KTRH sounded about like WWL does here, which is not bad but not local either. I'm willing to bet you can hear 740 in Mexico's Yucatan, and fellow member gar fla has reported KTRH at his location numerous times.
Here is a map from radio-locator. It is a bit generous in its estimation of the northern reach of the signal, but that's radio -locator for you.
Day: http://radio-locator.com/cgi-bin/pat?call=KTRH&service=AM&status=L&hours=D
Night: http://radio-locator.com/cgi-bin/pat?call=KTRH&service=AM&status=L&hours=N
KTRH is a regular here in Tampa at night and always there but usually it's behind WYGM, however there are times when KTRH will dominate.
I don't try for KCBS anymore. The only way it possibly could be heard is if the other stations on 740 were all off the air at the same time.
Besides WYGM and KTRH, I also sometimes get the Mexican station and CFZM makes an occasional appearance.
http://www.youtube.com/watch?v=_EFKuDkywPk
Daytime out at the Gulf less than 20 miles west of here, KTRH was a daytime regular behind WYGM during the time the Mexican station was off the air.
http://www.youtube.com/watch?v=2WcH0JN1irg
Now, the Mexican station is easily heard daytime.
http://www.youtube.com/watch?v=129aBeecaZA