Earth–ionosphere waveguide Earth and the ionosphere. The round-the-world nature of the waveguide produces resonances, like a cavity, which are at ~7 Hz. Radio propagation within the ionosphere depends on frequency, angle of incidence, time of day, season, Earth's magnetic field, and solar activity. At vertical incidence, waves with frequencies larger than the electron plasma frequency (f) of the F-layer maximum (1) f = 9 (N) kHz (N in cm is the electron density) can propagate through the ionosphere nearly undisturbed. Waves with frequencies smaller than f are reflected within the ionospheric D-, E-, and F-layers. f is of the order of 8–15
Waves Radio annual Scottish Week celebrations. Following the success of the initial broadcasts the station returned every summer, with the introduction of additional broadcasts made over the Christmas periods in 1994 and 1995. The station ceased broadcasting in July 1996 and was unable to transmit over the festive period due to the announcement of the full-time licence. After gaining a full-time licence, Waves Radio launched on 6 December 1997, from its current studios at Blackhouse Circle. Glenn Moir is the stations news editor, responsible for producing the daily local news bulletins. These are broadcast at 8.30am, 12.30pm and 5.30pm Monday - Friday.