Radio “Earths”

Manawatu Times, Volume LIV, Issue 6629, 17 August 1931, Page 5

Radio “Earths”

It is oftou found that a receiving aerial constructed in accordance with correct principals is connected to an earthing system which is little better than nothing at all. fho technical expect of Phillips Lamps (N.Z.) Ltd., states that with the normal typo of receiving aerial, there shouid be a substantial difference in reception with and without tho earth wire connected. It there is not, tho earthing arrangements aro due for an overhaul. Antenna and ground really function as tho alternative plates of a condenser which is charged up by the electrical pressure variations caused by the broadcasting station. A poor contact to one of these plates (tho earth) is quite as serious as a dirty inefficient contact to one of the tuning condensers in your set,, and is equivalent to the insertion of an cxtenal resistance in tho aerial circuit — the effect being a drop in received signal and increased broadness of tuning. A waterpipe is not always a good earth —where it goes directly to earth, it is likely to be good, but if it wanders round under the house before actually entering tho ground, it is likely to be worse than useless as it is then very effective in picking up electrical interference. A group of iron pipes driven some six feet into damp ground is still one of tho best earths—join ail pipes together with a “jumper” wire and solder the connections. Suitable alternatives are buried-in metal sheets, old motor car radiators etc. If you would oxcel at long distance radio reception, look well to your ‘earth.’