Abstract: A diversity switch combiner for use in systems for receiving wideband signals is arranged to split the received signal into separate channels each carrying a respective frequency band. Respective switch means are provided for each channel in order to switch the input of each channel between different antennas. A switch control determines the switch setting in accordance with the result of a comparison operation, preferably performed during a guard period, in which the signal qualities for different settings are compared.

Abstract: A multifilar antenna comprises n spaced antenna filaments, where n is an integer greater than 1; a matching circuit for matching the characteristic impedance of the antenna to that of a transmitting and/or receiving apparatus; a weighting circuit for applying gain and phase adjustments to signals passed to or from the n filaments; switch means associated with at least some of the filaments for selectively altering the electrical length and/or interconnections for the filaments; means for detecting electrical properties of the multifilar antenna with respect to the frequency, polarization and/or direction of propagation of a signal to be received or transmitted by the multifilar antenna and/or impedance matching of the antenna; and control means, responsive to the detecting means, for controlling the operation of the matching circuit, the weighting circuit and the switch means to adjust the properties of the multifilar antenna to suit better a current signal to be received or transmitted.