GBZ is the call sign of a British VLF transmitter on 19.6 kHz from Anthorn, Cumbria (formerly from Criggion, Powys), which is involved with transmitting encrypted signals to submarines. Although the signals of GBZ cannot be decrypted by common means, its reception - if its signal is shown in the form of spectrograms - is very interesting, because the signals of GBZ show figures looking like fishes, garlands and ornaments on the spectrograms.[1] 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.
