GB259300A - Improvements in or relating to frame aerials for use with radio receiving apparatus - Google Patents

Abstract

259,300. Igranic Electric Co., Ltd., and Wright, S. R. July 7, 1925. Aerials.-A collapsable frame aerial is provided with two separate windings for the purpose (a) of increasing the tuning range of the aerial, and (b) of providing a non-radiating coupling to a heterodyne receiver, combined with a switch for inserting the two windings alternatively in circuit and simultaneously earthing a mid-point tapping. The separate windings a and b, Fig. 1, are strung upon two sets of spacers c, d, carried at the extremities of four lattice-members e arranged in parallel pairs, and pivoted at f<2>, f<3>, f<4>, and in a slot g<1> at f<1> to upright members g, so that the whole arrangement will collapse as shown in Fig. 3. The spacing members c, d comprise a grooved insulating sleeve 14, Fig. 4, mounted on a hollow rivet 10 connecting the inner and outer slats of the supporting-members e. Two retaining pins m, Fig. 1, hold the windings in place in the collapsed position, and consist of bolts 15, Fig. 4, carrying an insulating-sleeve 16 which bears against the grooved sleeve 14 as shown. The upright supports g are connected at their lower ends by a block h, pivotally mounted in a foot j, to allow the frame to be rotated as a whole. Fig. 5 shows the switching device for inserting either the coils a', b, a<2> or the two outside coils a<1>, a<2> in circuit according as the arm of the switch is in the upper or lower position, a centre tapping being made to the point r<3> in each case.