The famous test meter Model 7x AVOMETER - "a multi-range A.C./D.C. Measuring Instrument providing 50 ranges of readings on a 5-inch hand-calibrated scale fitted with an anti-parallax mirror. Accuracy is within the limits laid down in Section 6 of B.S.S. 89/1954 for 5-inch Scale length Industrial Portable Instruments. Range selection is effected by means of two rotary switches, which are electrically interlocked. The total resistance of the meter is 500,000 ohms. The instrument is self-contained, compact and portable, simple to operate and almost impossible to damage electrically. It is protected by an automatic cut-out against damage through inadvertent overload." The instrument measures 8 x 7¼ x 4½ inches. (20.4 x 18.4 x 11.5 cms) and weighs 6¾ lbs. (3.05 kgs) including leads. This very famous and ubiquitous tool was manufactured by The Automatic Coil Winder & Electrical Equipment Co., Ltd. of Avocet House, 92-96 Vauxhall Bridge Road, London, S.W.1.
The AvoMeter was conceived in 1923 and maintained a distinct lead upon all its competitors for very many years. Tens of thousands of them were produced during World War II for the Armed Forces, Research Laboratories and factories etc.
Next on the shelf is the Absorption Wavemeter produced by Messrs. Raymart for the amateur radio enthusiast - constructed with very stable inductance and capacitance it depended on a resonance absorption in a tuned circuit in equipment construction work and aerial expirements.
Of unknown origin we illustrate here a "feed through" insulator of the type used for aerials and aerial feeders, in the days of the wooden outside shacks so beloved of amateurs of yore.