GB1156533A - Differential Input Signal Transfer System - Google Patents

Abstract

1,156,533. Aerials; delay lines. W. K. VOLKERS, and E. N. WILLIE. 22 June, 1966, No. 27828/66. Headings H3U and H4A. A dipole aerial system comprises one substantially fixed arm and one arm which is subject to movement relative to the fixed arm. Both arms are connected to a differential signal input device, and phase adjustment means are provided for maintaining the signals from the arms substantially in phase opposition. As described, a monopole 1, Fig. 2, having top capacitance loading 2 constitutes the fixed arm, and is connected through an adjustable delay line 14 to one input terminal 4 of an aerial coupling unit 6, whose output is delivered through a lead 8 to an R.F. amplifier 7. The other imput terminal 5 of the unit 6 is connected through blocking capacitors to a power lead 3, which constitutes the non-fixed arm of the aerial. Chokes 9, 10 isolate the power supply to the amplifier 7 and other station apparatus from the aerial. The delay line may alternatively be connected between the power lead and the aerial coupling unit (Fig. 1, not shown). The delay line may comprise a wire loop (31), Fig. 4 (not shown), provided with an adjustable rotary arm (33) which is coupled to it by capacitive means (34), (35). The delay line may alternatively be constituted by inductors in series associated with a tapping switch, the junction points of said inductors being connected through capacitors to earth (Fig. 5, not shown), or by a similar arrangement in which the inductors and the capacitors are transposed (Fig. 7, not shown), and in the former arrangement the common point of the capacitors may be earthed through a variable capacitor (Fig. 6, not shown) and in the latter arrangement the common point of the inductors may be earthed through a variable inductor (Fig. 8, not shown). In other embodiments (Figs. 9 and 10, not shown) simplified delay lines with only one capacitor and one inductor, either being variable, are used. In a further embodiment, the fixed aerial arm comprises a monopole (102), Fig. 11 (not shown), with top capacitance loading (103) and the other arm comprises a receiver chassis (105) in series with a power lead (106), a variable delay line (14) being interposed.