Carrier is generated by high precision, temperature controlled crystal oscillator, operates at a frequency 124 KHz. Output of this master oscillator is feed to harmonic generator, which supplies super group carrier frequencies. Required harmonics are selected by filters. 124 KHz frequency is subdivided into 4 KHz. This 4 KHz is then used in odd and even harmonic generators to provide channel frequencies spaced at 4 KHz interval (48 KHz interval for group velocity). Frequencies generated by two terminal stations is compared on a cathode ray oscilloscope. Go and return channels are incorporated in a common coaxial cable
Smallest cable have single coaxial tube used for special application or for lead in. Largest cable contains four coaxial tubes with each pair of tubes surrounded by audio pairs, this is used to extend connection to nearest station having higher frequency circuits. Audio pairs are also used for short audio circuits. Cable have an attenuation of 8 db per mile at 4 MHz. Repeaters are placed between 7 miles. Amplification produced at repeater station is of the order 50 db under the control of pilot frequency 4092 KHz. Variable equalising networks are controlled by two other pilot frequencies of 60 KHz and other in the middle range of frequency spectrum. Main type stations receive power from public supply undertaking
Auxiliary stations receive power from repeater stations through cable. Power supply frequencies are isolated from the transmission equipment by combination filter. Basic super group band is from 312 to 552 KHz, it has 12 basic groups, each have 12 channels thus a total of 60 channels.. Each basic groups have frequency range of 60 to 108 KHz. For good telephony transmit audios with 300 to 2500 hertz. Telemetering is used for above 2500 hertz