1230, 1240, 1340, 1400, 1450, and 1490 are the graveyard stations, called Class C. I read 20% of all AM stations at one time are/were on those 6 frequencies. Lower power on those stations (1KW day/night) and a ton of interference abound. The higher you go up in the AM band, the tougher it is to actually have reliable local signal. Ever try listening to AM 1690 WVON especially after sunset? Yikes!

Z