AERIALISMS

Sun (Auckland), Volume III, Issue 925, 19 March 1930, Page 7

AERIALISMS

To calculate the voltage drop across a resistance, multiply the number of ohms by the number of amps flowing through it. The use of a periodic aerial coupling is often beneficial in increasing selectivity, and cutting out unwanted noises. Not a few readers at this time make the annual overhaul of aeria! equipment, particularly halyards, pulleys, insulators, etc. If a new wooden aerial pole is being obtained, try capping the end with a tight-fitting tin lid, which will serve to protect it most effectively from the evil effects of our often very humid climate. To attain greater selectivity, it is ! not merely the receiving set itself ! that must receive attention. The whole system must come under rei view. The aerial has much to do with this question of selectivity, and we shall find as a rule that the average aerial is far too long to get real : selectivity. In these days of screenj grid valves an aerial of 80 to 100 ft is too long, and with an up-to-date . sensitive set 40 to COft is long enough. Where it is impossible to reduce the length of the aerial, it is found occasionally that a small condenser connected between the aerial and the set j improves selectivity. The value of the condenser should be .0001 or .0002 microfarads. Keep away mosquitoes and sleep in i comfort. Spray bedroom with Flytox [before retiring. Nun-pvisoEou:.—ig.