Edometer Cat 902 Mk I (1) & Mk II (2)

The Eddystone Edometer is a versatile solid-state instrument introduced in 1965, serving multiple functions in radio frequency testing and measurement. This transistorised device, essentially a modern equivalent of the grid-dip oscillator, can be used as a dip oscillator, absorption or heterodyne wavemeter, signal generator, modulation monitor, and audio oscillator.

Two versions of the Edometer were manufactured:

• MkI (1965)
• MkII (1967)

While similar in appearance, the MkII featured an updated scale, meter, and tuning knob. Both versions cover a fundamental frequency range of 390 kHz to 115 MHz across 7 ranges. The MkII Edometer was supplied in an elegant solid mahogany wood case with 7 coils, giving it a traditional, almost 19th-century scientific instrument appearance.

Features and Controls
The Edometer is equipped with three main controls:

• Combined power/sensitivity control
• Modulation switch
• Tuning control

Frequency Ranges (MkII)

1. 43 MHz – 115 MHz
2. 18 MHz – 43 MHz
3. 7.2 MHz – 18 MHz
4. 2.9 MHz – 7.2 MHz
5. 1.3 MHz – 2.9 MHz
6. 680 kHz – 1.3 MHz
7. 370 kHz – 700 kHz

It's worth noting that normal 'dip' operation is not possible on ranges 6 and 7, which are primarily intended for alignment purposes as an RF oscillator.

The MkI version initially came with a small 'drop-in' scale for ranges 6 and 7, extending coverage down to 390 kHz. However, the MkII eliminated this feature by marking all ranges directly on the dial, dispensing with the logging scale present on the MkI

Here you find 256 models, 127 with images and 46 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from Eddystone (Brand), Stratton and Co., Ltd., Eddystone Radio Ltd.; Birmingham