WEAK RECEPTION

Radio Record, Volume I, Issue 12, 7 October 1927, Page 15

WEAK RECEPTION

Your ear ig your best guide. ‘The signals becomé weaker as the 'B’’ battery voltage decreases. As long as the "B" battery contains useful energy the drop in voltage from day to day is so slight that it cannot be noticed. However, as the battery becomes exhausted its yoltage begins to fall more rapidly and its effect is noticed in markedly weaker signais. . When you have increasing in getting distant stations, and when the local stations fail.to come in as loud as usual, it is fair to assume that the B battery is exhausted and should be replaced. It will be found in most cases that this occurs when each 224-volt.. unit has dropped to the neighboyrhood of 17 volts. It is time then to throw them away. Your A battery should be tested in this case, hawever, for the same effect of weakened signals is — noticed when it, too, is becoming exhausted. | Lacking a suitable hydrometer, or voltmeter the best guide to the condition of the A battery is the brilliance of the filaments of the valves. If that is less than usual and does not increase perceptibly as you turn the rheostat the A battery is exhausted. However, these are by no means thie only causes of a weakening in signals. The weather has a great deal to do with distant radio reception. Electrical storms usually make distant reception difficult or impossible and cut down the volume of distant and even local stations. Fog, rain, sleet or snow may cover your aerial insulators and allow the signals to leak away to the ground before they reach your set. . Sometimes there even may be no_ appreciable change in the weather, yet atmospheric conditions may be such as to interfere with reception. Still another cause of weak signals is the exhaustion of tube filaments. The WD-11 and WD-12, UX-199 and C-299, and the UX-201A and C-301A valves. have a special filament whose life is generally ended not by burning out but by exhaustion of ceitain active materials. If your valves have been in use far a loug period a weakening in signals is perhaps a sign that new ones are needed. If your‘set is suddenly unsatisfactory, your valves are new and your batteries seem all right on test, call up a neighbonr or two and ask if they also are having difficulty. If they are, the trouble lies in conditions ne one can remedy, and in a day or so when the weather clears up your set will be work. mg as perfectly as ever; Iften a distant station will vary greatly in intensity from time to time, being alternately strong and weak. This is known as "fading,’? and likewise is due to atmospheric conditions beyond anyone’s control.