Short-Wave Oscillation

Radio Record, Volume III, Issue 15, 25 October 1929, Page 32

Short-Wave Oscillation

A DIRECT-COUPLED aerial is often used in a short-wave set, and in such cases it may be difficult to obtain oscillation. It may be possible to insert a larger reaction coil, but even this sometimes: will not ‘suffice. Short-wave receivers are often made with fixed | coils, and so it is desirable to find some cure, other than that mentioned. Disconnect the aerial from the set, which should -then oscillate easily. If this happens, couple the aerial to the grid coil by means of 4 small coil of about four.turns, varying the degree of coupling until the set oscillates without difficulty. If, however, the set does not oscillate at all without the aerial, the coils should be reconstructed on lowloss lines. At the same time, if it can be used satisfactorily, a direct-coupled aerial will often give stronger signals than those. given by a loose-coupled one.