Transatlantic News
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"Transatlantic News" was a regular column in the 1940 issues of Radio-Craft magazine, written by their European correspondent Major Ralph Hallows. As the title suggests, it reported on happenings from across the pond. A couple items caught my attention in this edition. One is about one of the first instances of the prediction of existence of a D-Layer in the ionosphere based on radio signal propagation characteristics noted by operators. The article estimates a height of about 30 miles, while the modern definition of the D-Layer places it at between 60 km (37 mi) to 90 km (56 mi). It also has a piece describing a simple method for silver plating without the need for supplying an electrical current. It involves making a paste of silver chloride and cream of tartar (potassium bitartrate) and rubbing it on the target metal. Supposedly the bond is as durable as electroplating. Transatlantic News
Radio-Craft European Correspondent
During the last 20 years reports have been received from time to time of the reflection of long-wave radio signals, apparently from a region considerably below the Heaviside or E-Layer. Such reflections occur only by day and are confined usually to a belt extending some 30 degrees north and south of the equator. They have been observed on very rare occasions in localities in England and Canada. During the war, reflections of Loran signals were found in tropical regions. A party of New Zealand physicists on Pitcairn Island kept records over a period of more than a year. An analysis of these by C. D. Ellyet furnishes convincing, evidence of the existence of a D-layer at a height of about 30 miles. In a series of nearly 2,000 daylight observations reflection from the D-layer was recorded on no less than 1,302 occasions; but in 1,200 observations made after dark only 2 instances of reflection were recorded. In the comparatively dense atmosphere at a height of 50 miles the recombination of atoms and electrons must be rapid once the sun has set and the ultraviolet rays no longer maintain a state of ionization. The meteors and meteoric dust which ionize the E-layer by night have lost their ionizing power by the time that they have penetrated as far as the D-layer. Ellyet concludes from his analysis of that D-layer reflection has been established beyond any possibility of doubt. He holds that it may be a factor of some importance in daytime radio transmission in the tropics, but that it occurs in other regions rarely and as a result of abnormal conditions. Simple Silver Plating Copper wire and copper strip, for high-frequency radio components, can be silver-plated without using electrical circuits by rubbing on a paste made from silver chloride and cream of tartar. The quantities and purity of either ingredient are not at all critical. The silver chloride is not stable in the presence of light, but is easily made. Either use 2 or 3 crystals of silver nitrate (lunar caustic) dissolved in water, or dissolve a scrap of silver in nitric acid and dilute the remaining fluid with water. Add to this a solution, of common salt in water, which should precipitate the white chloride. When this settles, pour off the excess liquid. Then add clean water and shake up. Allow the chloride to settle again, pour off the water, and repeat this washing process 3 or 4 times. Finally add dry cream of tartar to form a paste. Clean the' copper well, moisten with a salt solution, and then rub on the paste with a soft rag. This forms a coating of silver (not quicksilver) which is permanent in its qualities. Thickness of the finished coat depends on the amount of rubbing and the process can be repeated as many times as necessary. - R. Kerr in Radio and Hobbies (Australia).
Posted July 2, 2020 |
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