588,638. Valve circuits; aerial coupling arrangements. MARCONI'S WIRELESS TELEGRAPH CO., Ltd. Feb. 8, 1945, No. 3249. Convention date, Feb. 9, 1944. [Class 40 (v)] In a high-frequency amplifier, the coupling coil 10, connecting a valve 2 to a load, is mounted by insulators 58 on a conducting panel 50, the end remote from the valve being coupled by a capacitor 14 to the panel, a resistor 52 maintaining the two plates of the capacitor at the same D.C. potential, while the panel 50 is coupled to earth by the R.F. byepass capacitors 68, designed to withstand the full voltage of the anode supply. The valves 2, 4 are preferably arranged in push-pull and feed over further coupling coils 60 and capacitors 18, 22, the capacitors 15 connected to the load, the H.T. supply being fed to the centre tap of inductor. Where the panel 50 and earthed plate are sufficiently close, the capacitor 68 may be omitted.