GBZ
GBZ is the callsign of a
British VLF transmitter, which transmits on 19.6 kHz from
Anthorn, Cumbria (formerly from
Criggion, Powys) encoded signals to
submarines. Although the signals of GBZ cannot be decoded by common means, its reception - if its signal is shown in form of spectrograms - is very interesting, because the signals of GBZ show figures looking like fishes, garlands and ornaments on the
spectrograms. At certain times these signals are also transmitted as strong pulses, so-called
superpulses, which can oversteer the amplifier of a PC
soundcard at distances of a hundred kilometres away from transmission site.
* http://www.vlf.it/harald/strangerec.htm
* http://www.vlf.it/trond2/15-20khz.html
*
Spectrogram of superpulse
