GB249824A - Adjustment means for wireless receiving apparatus - Google Patents

Abstract

249,824. Slocumb, L. Q. March 27, 1925, [Convention date]. Thermionic amplifiers and detectors; tuning apparatus, construction and control of.-In adjustment means for receiving sets, a single handle is arranged so that rotary movement adjusts one variable and lateral movement another variable. Fig. 2 shows a condenser mounted on a plate 60 slidable in guides 61, 62 and carrying a coil 4 so that transverse movement adjusts the coupling between coils 2, 4, and rotary movement adjusts the condenser 3. An extension 71 may be provided for fine adjustment. The Specification as open to inspection under Sect. 91 (3) (a) comprises also a reflex wireless receiver consisting of amplifying valves 7, 16, 18, Fig. 1 (Cancelled), and transformers 9, 12 which serve for both audio and radio frequency coupling. The output of amplifying valve 18 comprises a sound reproducer 13 shunted by condenser 10<b> and a single turn loop 33 coupled to a closed circuit 34, 51 associated with a detecting valve 27. The loop 33 is so connected as to form part of the plate circuit of each of the amplifying valves 7, 16, 18. The secondary of the output transformer 21 of the detecting valve 27 is arranged in series with the tuned circuit 2, 3 associated with the input of the amplifying valve 7. Reaction coils 4, 50 are provided and may be reversed to obtain stability, in addition a variable resistance 19 may be provided to give stability. The variable resistance 19 may comprise an insulating drum 75, Fig. 4 (Cancelled), provided with a circular wedge of graphite 78 engaged by a wiper 79. A notch 81 serves as an indicator and prevents the wiper from spreading the graphite over the uncoated surface so that high resistances may be obtained. This subject-matter does not appear in the Specification as accepted.