FM broadcasting
VHF Radio waves do not travel far beyond the visual horizon, so reception distances for FM stations are usually limited to 30–40 miles (50–65 km) They can also be blocked by hills or buildings.
WHA (AM)
Initially there were no formal standards for stations providing a broadcast service, so there was no problem with 9XM broadcasting under an Experimental license. However, effective December 1, 1921, the Department of Commerce adopted regulations defining a broadcast service. The new regulations specified two transmitting wavelengths — 360 meters (833 kHz) for "entertainment", and 485 meters (619 kHz) for "market and weather reports" — and also required stations making broadcasts intended for the general public to hold a "Limited Commercial" license. Professor Terry filed an application for the new license, and on January 13, 1922 the University was issued its first broadcasting station authorization, with the randomly assigned call letters of WHA. In addition to the two broadcasting wavelengths, the station was authorized to use 410 meters (731 kHz) "for intercommunication between college stations".