Patent GB-664701-A (GB)
Title: Improvements in or relating to radio relay stations
IPC: H04B7/14
Filed: 1949-01-28
Abstract: 664,701. Radio signalling; directive radio systems. WESTERN ELECTRIC CO., Inc. Jan. 28, 1949 [Feb. 3, 1948], No. 2409/49. Classes 40 (v) and 40 (vii). A radio relay station comprises two antennµ for association with different links of the relay system, and a radio lens or refractor is positioned between and for common use by said antennae. The antennµ are located off the axis .of the lens. Fig. 1 shows a radio relay system comprising a transmitter M, three relay stations R1, R2 and R3, and a receiver N. The energy from transmitter M is transmitted from horn antenna 5 which is at the focus of radio lens 2, to the relay station R1 where the incoming wave energy is focused by biconcave lens 10 on to receiving horn antenna 8. The received signals, after being amplified and changed in frequency by repeater unit 13, are transmitted from horn aerial 5 to the lens 10 which converts the spherical wave-front from horn 5 into a plane wave-front. The signals are similarly received and retransmitted from relay stations R2 and R3, and then received at receiving station N which comprises a lens 2 and associated antenna 8. Modifications are described in which the horn antennµ 5 and 8 are displaced horizontally from the axis of the lens, or in which each antenna deals with both transmitting and receiving frequencies in conjunction with two unidirectional selective repeater units. In this case polarization diversity may also be employed. Fig. 6 shows a relay arrangement utilizing a dielectric guide prism refractor 71, in which two channels are received and retransmitted in the same forward direction. Wave Wa of frequency Fa is bent towards receiving antenna 72, and the energy is then amplified and retransmitted at a different frequency Fc from antenna 74 and again refracted and transmitted to the next station in the direction Wc. Incoming wave Wb at frequency Fb is similarly received by antenna 75 and retransmitted at frequency Fd from antenna 77 to continue as the wave Wd. The frequencies Fa, Fb, Fc, Fd are made successively smaller, so that the angle of deviation of these waves through the prism is successively increased, and the antennµ 72, 75, 74, 77 are then spaced apart according to the appropriate duration angle. A lens 32 is placed at the open end of each horn antenna. In a modified arrangement involving a single channel a concave lens is placed on each side of the prism refractor, so that the waves are focused on the receiving and transmitting antenna. horns. A two-way relay station is also described, in which one section comprises two receiving antennµ which are associated with a lens in the same way as the transmitting and receiving antennµ of the relay station in Fig. 1, and also a second section which contains a similar arrangement of two transmitting antennae and a lens. Each receiving antenna is connected via repeater equipment with a transmitting antenna, and the receiving and transmitting sections are spaced apart a plurality of wavelengths so that cross-talk is reduced. Specifications 650,767, 655,936, 664,672 and 664,673 are referred to.