Pierce Earth System

Radio Record, Volume IV, Issue 34, 6 March 1931, Page 12

Pierce Earth System

Effectiveness Questioned

A GREAT amount of attention has been focused on the Pierce earth lately. In fact, My. Pierce is quite a personality of importance in New Zealand radio matters. Many of the older readers will recall the first description of his earthing system pub; lished in our issue of March 380, 1928. Since that time it has been applied by numerous enthusiasts with varying results, Following the publication of the original article there was such a wave © of interest that the "Radio Record" sponsored a competition to find out if the earth was really having an effect on reception. The result has had its sequel in the recent DX competition, for the prize was won by Mr. Ellis, of Okato, who only last week carried off the DX.Club honours and was accorded the position of DX king. In his letter describing the improvement brought about by the system, Mr. Ellis remarked: "Before installing this earth I could get 2FC’s carrier wave only at mid-day, and now I can bring it in quite clearly on the phones. I could not get an American station till I adopted this earth, and now they come in one after another when conditions are good." Mr. Bilis was allowed 69 American stations in the DX competition, On the story of the original installation we shall -not dwell. It will be sufficient to say that it was first used by an American enthusiast, Pierce, who achieved great results with it in the early days of radio. His experiences were published in many journals and aroused tremendous interest. Later measurements were made to justify or disprove the statements, and we shall refer to their findings later, The essence of the system is shown in the accompanying illustration. Outside the window the wire from the set joins a binding post from which twelve wires lead to twelve pipes driven in the ground. Pierce said that each new pipe added to the volume, increased the selectivity and reduced the body capacity effect. So he added one after another. A leaky motor

radiator was sunk in the ground, at the ‘end of the row of pipes, with its cap just above the surface of the earth, so that water could be poured into it. The ground clamps on the pipes were kept bright, and Pierce added that he put new ones on every few weeks, — That, in brief, is an account of the Pierce earth system. As we remarked earlier, many have tried it and found that reception improved. Others have probably installed it to no purpose. We referred a few moments earlier to measurements. They showed fairly conclusively that a system of multiple earths was of little use unless the pipes were well separated. The following is an extract from a paper read before the American Bureau of Standards :- "The diameter of the pipe employed for an earth tube is of no importance, Neither is it of any benefit to drive a number of pipes in close proximity. ‘If two or more pipes are driven ’ 6 to 10 feet distant from one another, however, the resistance decreases almost in proportion to the number of pipes, "This practice is only worth while, though, where an unusually low earth- contact resistance is required or where the soil is dry, sandy, or gravelly. "The necessity for separating the two or more pipes forming the earth contact arises from the fact that the earth in immediate proximity to the first pipe driven is already carrying a dense current. "Tf another pipe is driven into the field of this current, the immediately adjacent earth can obviously not pass ‘appreciably more current and distribute it further afield, The second pipe must be driven outside the dense field from the first pipe, and it will then be able to play its proper part in the distribution of the current over a large cross-sectional area of the earth." Here we are again, the old controversy of theory and practice. . Let us reopen it. What do listeners think and what is their experience?