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Show RECEIVING SETS Broadly speaking, the receiving set consists of the antenna or aerial, the tuner, the detector and the receiver, but aside from the aerial, each part of the instrument Is made" up of stveral other units and appliances, each devised and used for a definite purpose. The aerial, which Is a wire designed to Interrupt or catch a portion of tbe continuous waes (always referred to In wireless telephone parlance as C. W.) consists of a single wire, for an-V7 an-V7 like wireless telegraphy, a number of ' ArtAL ' strand or wires ia of no advantage In re- celvlng. and still more remarkable, It - I makes no difference whether the wire be errrero y t bure or Insulated, for the C. W. used in 3 I radio telephony penetrates solids of ev- rvAff Ok ery kind. Indeed, a wire stretched around 4ttci" -A a room or through a hallway Indoors, or I " even a metal bedstead or bed spring, may serve as ari aerial for receiving wireless F'ff telephone messages, although far better "J"fmx0 ' re8u,ts are secured by properly Installed aerials out of doors. And here It may be wise to Impress all users of receiving sets with the fact that the lo&ger the aerial and the higher above the ground the better will be the results obtained, although an aerial 150 feet long and well above other large buildings will serve every purport. Moreover, It makes no difference whether the aerial Is borl-sontal, borl-sontal, vertical or at an angle, provided it Is thoroughly Insulated from all surroundings, sur-roundings, and very good results have been obtained by aerials run vertically up an air shaft or along tbe side of n building. So too, the lend-in, or wire connecting the aerial with the receiving Instrument, serves as an aerial itself nd therefore a long lead-In with a short aerial will serve almost" ns well as a long aerial and short lead-In, which is a tremendous advantage to dwellers in hotels, apartment houses, etc., where It U very difficult or impossible to Instull a long and lofty aerial on the Voof. But before going Into detulla and describing describ-ing the Installation of nerials, let us consider the rest of the receiving equipment equip-ment and thoroughly understand Its principles. The detector, without which It would be Impossible to register or detect the mlhute currents of waves which pass through the neiiul Is u very Important port of the mechanism. There are two l.ves of detectors in use, me nrai known as the crystal detector and the other as the vacuum tube. In the former, for-mer, a crystal of some mineral preferably galena is used, while In the latter, lat-ter, a form of incandescent lamp with especially prepared filament Is employed Of the two, the former Is the cheaper and Is used on most of the cheap, reudy-made reudy-made sets, but It has limitations and is not nearly as satisfactory In many ways as the vacuum tube, as will be explained later. The third unit or tuner is the means by which the entire apparatus Is made to pick np the sounds from some station or elsewhere and by means of which other sounds are shut out, for only by means of the tuner can the receiving set be placed in synchronism, or tune" with the waves carrying the sounds you wish to bear. The last unit or receiver Is merely a telephone receiver made for the purpose and which, on small set, Is worn over the ears exactly ns in receiving wireless telegraph men suges. Figure 7 illustrates In diagrammatic form these units with tlielr relative positions In the set, but lliere are several good accessories which are essential to juod results. |
