Wavemeter Class D No. 1

Although not build as substantial and accurate as the US Signal Corps SCR-211, the British Wavemeter Class D No. 1 had a similar function: a simple to use self contained portable field instrument for setting up a receiver or transmitter to a given frequency or checking frequency calibration of any receiver or transmitter.

Initially known as 'Corrector Frequency', its use was confined to the British Army only. The set was normally carried and transported in its wooden transport case (Case Transit No. 7).

The later issued Wavemeter Class D No. 2 (1945) is similar in function, but the problems arising when using Wavemeter Class D No. 1 in choosing the right frequency from a large number emitted has been eliminated.

• Frequency coverage specified 1.9-8MHz in two ranges, but may be used at lower and higher frequencies.
• Powered by external 6V accumulator; HT obtained via internal vibrator and bridge rectifier.
• Accuracy within +/-2kHz over specified frequency range.
• 1MHz check frequencies are provided up to 25MHz.
• Headphones should be standard low resistance e.g. British Army type CLR or DLR.
• Simple to use, inexpensive to produce.

Detailed front panel view of Wavemeter Class D No. 1. The headphones output jack (right hand bottom corner) is not the original and should have a round front panel plate indicating 'LR Phones'.

Inside view of Wavemeter Class D No. 1 showing valve type ARTH2, vibrator and spares. Made in 1943, note the perfect condition of the rubber bands holding the valves in position.