Radio beam and Radio beacon

Radio beam noun - A signal transmitted along a narrow path; guides airplane pilots in darkness or bad weather.

Radio beacon and radio beam are semantically related In some cases you can replace phrase "Radio beacon" with "Radio beam", this phrases are similar.

Radio beacon noun - A radio station that broadcasts a directional signal for navigational purposes.

Radio beam and radio beacon are semantically related in navigation signal topic. You can use "Radio beam" instead a noun phrase "Radio beacon".