Radio communication

Radio waves, as one form of electromagnetic wave, consist of electric and magnetic fields vibrating mutually at right angles to each other in space. A transmitter feeds a transmitting aerial from which radio waves are broadcast to a receiving aerial feeding a receiver. The transmitter is composed of a generator of a radio frequency carrier wave which is modulated in accordance with the electric currents carrying the signal amplified from a microphone. If the receiving aerial is tuned to the frequency of the carrier wave, the receiver is able to selectively amplify and demodulate the transmitted signal so as to operate a loudspeaker. Amplification is achieved by devices (such as vacuum tubes or transistors) based on use of the small input signal to control the flows of larger negative (or positive) charges that are collected as the output signal. Tuning is achieved using an electronic circuit containing both inductance and capacitance such that it is capable of resonance. Thus when the capacitator discharges through the inductor this results in the capacitator being recharged in the opposite sense with which it then discharges again, thus continuing this oscillatory cycle (as long as external energy is supplied). The frequency of oscillation may then be varied by adjusting the values of the inductance and capacitance.

The flow of information emanating from any individual or group, whether in the form of documents, speeches or media activity, may be compound to radio waves. A distinctive communication is achieved by modulating this flow. Such communications can only be satisfactorily received by adjusting one's concept scheme to the frame of reference of the originator and decoding the symbols used to extract the referents they carry. There may be considerable interference between various flow of information, to the extent that it may be very difficult to receive a clear and coherent pattern of information from which meaningful referents may be extracted.

The degree to which the various component devices needed for radio communication are distinguished, the refinements possible to improve the quality of communication, and the degree of development of the theory governing their operation.

Considerable use is made of phrases such as 'being on the same wavelength' or 'frequency'. Some people are recognized as being 'tuned in' to the latest gossip or fashions. After the quality of a confusing explanation has been improved, the content may be referred to as being 'received loud and clear'. These suggest an implicit understanding of other parallels to radio communication but no attempt seems to have been made to make the metaphor coherent. Whilst there has been considerable attention to the transfer of information in a digital or particle-form, there is little complementary recognition of its transmission/reception in a wave-form or of how this may be facilitated.

Antenna arrays and concept arrays and their design. Mutually orthogonal electric and magnetic fields in carrier waves compared with mutually orthogonal semantic dichotomies providing the dynamic framework for the distinctions alternatively stressed in any communication ('semantic screening'). The process of amplifying subtle distinctions in a weak signal or embodying subtle distinctions into a flow of language. Ability to receive coherent messages from schools of thought distant in space and time. Radio noise, interference and jamming. Transmission power and quality in relation to long, medium, short-wave and UHF transmission. Radio telescope. Radar.