Inaccurate tuning causes noisy reception and ruins the quality. Most sets are accurately tuned when a slight movement of the tuning knob in either direction makes the tone sound shriller.
Keep your receiver in condition
Your receiver is a scientific instrument.
It needs skilled attention from time to time to maintain its original performance, because it contains parts that wear out and adjustments that must be kept just right. The performance falls off very gradually, so that you don’t notice anything from day to day or even from week to week, but you would probably be astonished at the improvement if you had any weak valves replaced and the internal tuned circuits ‘realigned’.
At regular intervals
have your set examined by a radio serviceman who is expert in your particular make of receiver. Do not wait until an expensive breakdown occurs, but seek skilled advice when you notice anything unusual, such as a loud hum, stations tuning at the wrong position on the dial or insufficient volume with the volume control at the normal setting.