Valve Radio and Audio Repair Handbook

Chapter 12

Some more special features found in superhets

Chas E. Miller

Tuning indicators

The greatly improved selectivity of the superhet caused problems for some listeners who had recently converted to them from antiquated TRFs. In the latter it was usually possible to get reasonably good reception even if the tuning control(s) were not set accurately; indeed, in the absence of proper volume controls it was common practice deliberately to de-tune a set to reduce the output. With a superhet, however, mis tuning whether unintentional or deliberate results in very harsh reception due to only part of one sideband being reproduced (sixty-five years of experience have not eradicated completely the problem!).

To assist listeners to tune their sets properly ...