To the Editor of the "Norru-Cuina Dary News"
St—Inreresrep in his yesterday's letter enquired whether there is a "special Providence which, looks after the radio sets and guides the radio waves to their antennas?" There may be a special broadcasting station in Providence, New Jersey, USA?
However, Inrenestep was really searching for information for he mentioned that from enquiries made among his friends, the B.B.C. Derby "Broadcast was not well received by some of them who had sets far bigger than the 10-tube one which was used by your staff and which gave such excellent results.
It is a common expectation that quality/volume depends directly upon the number of valves contained in a receiver, This is by no means the case, but to meet the popular demand which is based on this deep-sented fallacy, certain receivers, as Gescribed in a recent disclosure, have actually been fitted with "dummy" valves which can be removed without affecting the characteristics of the receiver in any way.
The major factor in securing best possible reception is the quality and design of the individual valves and the way in which they are relatively connected, The latest developments in valves have been in the direction of producing current-saving cathodes and the. specialization of types:
Among the new constructional principles Min valves I would mention that of the Directed Electron Beam which has certainly been an outstanding improvement. The prolem of reducing the noise-to-signal tatie, which is linked in with the problem of volume control, is another feature in comparatively recent valve development, In the set which was used by your Editorial staff one of the, characteristics of certain of the valves is that the transit-time effect of the oscillator and the troublesome phenomenon known gs "Frequency Brit" have been duced to a minimum while the induction effect has been compensated' by the incorporation of a condenser with a resistance and thus the conversion slope has been increased.
Up to the present,, short wave reception has been limited by the noise level but fortunately another considerable valve improvement has been the introduction of a superior
signal ratio, Also the control' protype of valve having low noke-toblem has been largely solved" not only by modifying the grid bias but by modifying the screen grid voltage at one and the same time.
Other radio receiver characteristics which have unfortunately been ncgleeted by many makers are those concerning mechanical and electrical robustness which are an absolute necessity here in China but are by no means so important in the countries of their manufacture where what may. be described as normal weather conditions generally prevail Using the same make of set as that used by your staff on Wednesday T have had consistent A.1 results when listening in to Daventry on the 15 m: etre band for the last three weeks, but I always bear in mind that any day this may ba impossible due to eny one or a combination of many factors, including the varying length of the daylight path in this 16 metre beam between Daventry and Shanghai, intensity and position of sun spots, the season of the year, possible electrical disturbances in the path of the beam which not only include atmospheric electrical "storms" but our er-present enemies—mctor cars, lifts, tremears, poor. fuse còn-tacts in house fuses, wiring defects and a thousand and one other sources of electrical. variations to say nothing of the eccentricities of my cook with the electric cooker etc.
Text read from the printed page and cleaned; old type leaves the occasional error.