A more scientific approach to many problems, particularly to the details of receiver design, now becomes evident. It had already been shown (by M G Scroggie) that even a very low value of impedance common to several anode circuits could completely spoil the performance of an AF amplifier. This trouble was overcome by 'decoupling' individual circuits, a method originated by Ferrantio The isolation of circuits by 'scientific wiring' was also described.
By now, the neutralised triode was being replaced by the screened tetrode for RF amplification. Output pentodes, fed directly from the detector, helped to simplify and cheapen broadcast receivers: the three-valve set was becoming the most popular.
Detection of signal echoes 'from the depth of space', with a time delay of 15 sec, gave a foretaste of extra-terrestrial communication.