. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. 582 BELL SYSTEM TECHNICAL JOURNAL in the case of the so-called pole-pairs which straddle the pole and whose wires are about 18 inches apart. (See Figure 9.) The con- struction includes pins and glass insulators for supporting the wires. 10'-0" ^, 4^ 4. 4- 4r^^^ M 4 ^^ -^. Figure 9—Showing arrangement of wires on telephone pole line There are three gauges of wire in common use in the telephone plant, having diameters of 104, 128 and 165 mils,* respectively. The lar
. The Bell System technical journal. Telecommunication; Electric engineering; Communication; Electronics; Science; Technology. 582 BELL SYSTEM TECHNICAL JOURNAL in the case of the so-called pole-pairs which straddle the pole and whose wires are about 18 inches apart. (See Figure 9.) The con- struction includes pins and glass insulators for supporting the wires. 10'-0" ^, 4^ 4. 4- 4r^^^ M 4 ^^ -^. Figure 9—Showing arrangement of wires on telephone pole line There are three gauges of wire in common use in the telephone plant, having diameters of 104, 128 and 165 mils,* respectively. The largest gauge, 165-mil pairs naturally afford the lowest attenuation and have been generally used in connection with the application of the longer systems. The pairs of this sized conductor are, however, now fairly well used up for carrier purposes and new installations are being made more often on the smaller diameter circuits. Typical attenuation curves for the three gauges of wire and the extremes of weather conditions are given in Figure 10. It will be noted that the wet weather attenuation may be as much as 40 per cent higher than the dry weather attenuation. Also, these variations are greater at the higher frequencies. It is interesting in this connection to consider the effect of the possible variation in a practical case. Take, for example, a 165-mil pair 200 miles long with a carrier channel frequency at 25 kilocycles. This means a total attenuation of 20 TU in dry weather and 29 TU in extremely wet weather, a variation of 9 TU or a current ratio of about 3 to 1. In the case of a still longer line these possible variations present rather startling figures. For example, in a 1,000-mile circuit the variation would be five times the above or 45 TU, which would *The term " mil " as here used is equivalent to Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appea
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttechnology, bookyear1
