As a result of the plan most medium wave ( and later longwave ) stations outside North and South America operate on exact multiples of 9 kHz which helps reduce heterodyne interference.
2.
While the wavelength was announced as " 266 metres " the station experimented with frequencies between 1133 and 1137.5 kHz and tended to suffer nighttime heterodyne interference from stations in Zagreb and elsewhere.
3.
Caroline returned on 9 March 1977 on 953 kHz, actually 315 metres but announced as 319 . This gave reasonable reception by day but strong heterodyne interference at night because the transmitter crystal was off-channel.
4.
In the 1990s, LPB, Inc ., possibly the largest manufacturer of these transmission systems, designed and supplied several extensive campus-based systems that included fiber-optic links between linear amplifiers to prevent heterodyne interference.
मोबाइल