I was always enjoyed medium wave DXing. But I’ve never really heard any good strong signals coming from America. These days, with massive interference all over the bands, it’s not easy to hear anything. However, I have discovered so-called clear channel frequencies used by certain American AM stations.
In the U.S. and some other countries, certain medium wave frequencies were designated as clear channels so that one dominant station could cover a large area without interference from other stations. This was particularly useful at night when medium wave signals can travel hundreds or even thousands of miles via skywave propagation. Historically, stations like WLW on 700 kHz or WLS on 890 kHz could be heard across much of North America at night. Major U.S. Class A stations, formerly called ‘clear channel’ stations, still enjoy the highest protection, especially at night. Most run 50,000 watts.
Well-known examples:
WLW – 700 kHz Cincinnati, OH. One of the most powerful and historically important AM stations.
WSM – 650 kHz Nashville, TN. Famous for the Grand Ole Opry; heard across much of the U.S. at night.
WGN – 720 kHz Chicago, IL. Strong Midwest night time coverage.
KMOX – 1120 kHz St. Louis, MO. Long distance night time reach; major emergency broadcaster.
WBZ – 1030 kHz Boston, MA.
KNX – 1070 kHz Los Angeles, CA. Uses directional antennas to protect other Class A stations.
KOA – 850 kHz Denver, CO.
KFI – 640 kHz Los Angeles, CA.
WWL – 870 kHz New Orleans, LA.
WABC – 770 kHz New York, NY.
These days, Class A stations typically have:
50,000 watts of power.
Protected night time skywave coverage.
Priority over other stations on the same frequency.
Emergency Alert System (EAS) roles.
Other stations on the same frequency must:
Reduce power.
Use directional antennas.
Or shut down at night.
Why they exist:
To provide wide-area coverage, especially to rural regions
To ensure emergency information could reach large populations
To reduce interference between stations at night
How far away can they be heard?
At night, under good conditions: 300–1,000+ miles is common. Sometimes even farther with clear ionospheric conditions. This is why you can still hear distant AM stations after sunset.
Why they still matter:
Even in the internet era, these stations are valuable because AM works when cell networks fail. Wide area coverage helps during natural disasters.
Clear Channel Examples (U.S.)
650 kHz
700 kHz
720 kHz
750 kHz
760 kHz
770 kHz
840 kHz
880 kHz
1020 kHz
1030 kHz
1040 kHz
1070 kHz
1100 kHz
1120 kHz
1160 kHz
1180 kHz
1200 kHz
1210 kHz
1500 kHz
1510 kHz
1520 kHz