Racal SA.97 Wobbulator page 5

I am told there were two sets of plug-ins for the SA.97 so that it could be used for setting up the 37.5MHz filter as well as the 40MHz filter. Whereas this may sound logical, as previously mentioned, the 37.5MHz filter does not require a wobbulator for alignment and what of the Marker Generator? It is clearly intended to work at 40MHz. Thus I have to conclude that unless someone can prove otherwise, I am guessing that the SA.97 was only ever fitted with 40MHz plug-ins.

Above: 40MHz Sweep Generator, sync’d to the Sweep Timebase. A secondary RF output is fed to the Marker Generator.

Valves:2 x ECC81

Above: 40MHz Lin/Log Amplifier. The output is fed via an external cable to the display Y-channel.

Valves:3 x EF91

Other circuits:

Timebase and X-channel valve line-up: EF94, 12AU7, 2 xZ759, 150C4

Y-channel valve line-up: 2 x Z759, 150C4

Astigmatism control valve line-up: EF91, EL821, 85A2

Marker Generator valve line-up: ECC81, 2 x EF91, ECF80