RECEIVING SHORT WAVES

Shannon News, 1 November 1927, Page 3

RECEIVING SHORT WAVES

DIFFICULTIES EXPLAINED. The development of short-wave, transmission has outrun that of reception, for, apart from the superheterodyne, there remains only the simple two' or three-valve set. , The tuning of a short-wave receiver calls for reasonable skill, especially, if telephony is to be heard. If we take a station of, say. 500 wave-length we know that its waves vibrate or oscillate 600,000 times a:, second. When these waves are modulated by speech or music the frequency of oscillation may vary between 595,000 and 605,000. For a short-wave station operating on 30 metres the waves oscillate at a frequency of 10,000,000 a second. Thua the speech and music variations of plus and minus 5000 a second become more difficult to separate in the receiver. However, the modern shortwave receivers or adapters are so designed that a comparatively large movement in tuning controls makes only small alteration to wave-length, and so. after a little practice, , the /operation of a short-wave set offers few difficulties, provided, of course, it is designed correctly.