Published on CIA FOIA (foia.cia.gov) (https://www.cia.gov/readingroom)


SCIENTIFIC

Document Type: 
CREST [1]
Collection: 
General CIA Records [2]
Document Number (FOIA) /ESDN (CREST): 
CIA-RDP80-00809A000600120033-2
Release Decision: 
RIPPUB
Original Classification: 
U
Document Page Count: 
5
Document Creation Date: 
December 22, 2016
Document Release Date: 
May 19, 2011
Sequence Number: 
33
Case Number: 
Publication Date: 
December 11, 1956
Content Type: 
REPORT
File: 
AttachmentSize
PDF icon CIA-RDP80-00809A000600120033-2.pdf [3]209.36 KB
Body: 
Sanitized Copy Approved for Release 2011/05/19: CIA-RDP80-00809A000600120033-2 STAT Sanitized Copy Approved for Release 2011/05/19: CIA-RDP80-00809A000600120033-2 Sanitized Copy Approved for Release 2011/05/19: CIA-RDP80-00809A000600120033-2 USE OF LOADING COILS ON CABLES WITH POLYVINYL-CRLC*UDE EMPLOYED IN INTRARAYON COMMUNICATIONS NETS yestnik Sv&zi [Communication News], No 8, 1953, Moscow, Pages 15-16 A. I. Semenov, F'ngineer The article discusses a method of loading cable lines of intra- rayon communication and considers a method of mounting the inductance coils. At the present time the networks of the intrarayon communication (VRS) at the present time make widespread use of cables (wire pairs) with poly- vinyl-chloride insulation. The industry produces such cables under the trademark PRVPM with copper wires 0.8, 1, and 1.2 mm in diameter. The radio thickness of the insulation in the cables is respectively 1 ? 0.2, 1.2 ? 0.2, and 1.4 t 0.2 mm. The electrical parameters of the nonloaded cables with polyvinyl-chlor- ide insulation at a temperature of ? 200 are given in Table 1. f kc P OC Z mnep/km radian/km ohm Z cos ohm -Z sin ohm PRVPM-0.8 mm 0.3 88 '0.084 587 42?30' 432 396 (Ro = 72.2 ohm/km; C - 0.111 mfd/km; 0.8 149 0.141 353 41?24' 265 234 L = 0.816 mh/km) 2.4 237 0.263 207 38?36' 163 128 PRVPM-1 an (Ro - 47 ohm/km; 0.3 72 0.069 467 42?05' 356 312 C = 0.114 mfd/km; 0.8 115 0.117 290 40?32' 220 188 L - 0.802 mh/km) 2.4 185 0.223 166 35?40' 135 97 PRVPM-l.2 ma (R - 32.8 ohm/km; 0.3 60 0.059 386 41?41' 289 257 0 C - 0.116 mfd/k54 0.8 96 0.101 237 39?32' 183 151 L - 0.792 mh/km) 2.4 148 0.197 140 32?55' 118 76 According to Rukovodstvc po stroitel'stvu i remontu soorusheniy vnutri- r&yonnoy sv asi [Instructions for the Constrrction and Repair of Intrarayon Structures , Part II, 1949, Svyas'isdat, thb attenuation in the section com- prising the intrarsyon network telephone subscriber set and the interurban telephone station of the rayon central station should not exceed one nep at a frequency of 800 cycles, and for certain rayons 1.6 nep at the sage fre- quency (Figure 1). The maximum length of the line from the telephone not of the subscriber ml we iutraru9iuu motwork to the int. :sham rayon Contra,. telephone station, corresponding to these norms, is indicated in Table 2. Sanitized Copy Approved for Release 2011/05/19: CIA-RDP80-00809A000600120033-2 STAT Sanitized Copy Approved for Release 2011/05/19: CIA-RDP80-00809A000600120033-2 Table 2 Maximum permissible length of line, in km Double-step construction Single-step construction of net of net u = 0"v aup b 1.6 uop b = 1.G u p b = 0.5 nep b = 1.1 nep b = 0.85 nep line .line line YRVYM-U.6 mm s.aU 1. iU PRVPM-1.0 mm 4.35 9.55 It is evident fron the table that the maximum telephoning distance us- ing cables with polyvinyl-chloride insulation does not exceed 11.5 km. Such a distance is inadequate for rayons with large territories. This distance can be increased either by installing repeaters, which is difficult in practice, or by artificially increasing the inductance of the line. The inductance is usually increased artificially by loading the tele- phone network. Essentially the method consists of inserting in the cable line inductance coils at equal distances from each other, as shown schemat- ically in Figure 2. A loaded line can be considered as consisting of indi- vidual links, each link containing a coil and a section of cable on each side. To load lines on the intrarayon communication networks the Russian industry produces coils which have an inductance of 70 mh. The loading spacing S (distance between coils) is taken to be 1 km. Under these condi- tions the channel occupies a frequency band from 300 to 2,400 cycles. :'he inductance coil has a cast iron dish (case) with a cover and 2 PRVPII paired lead-in wires. Inside the dish is a toroidal core, made of pressed powdered magnetodto.eetric. The corn carries a winding made of insulated copper wire. The core is impregnated with a substance containing rosin, paraffin, and natural rubber. The electrical parameters of cables with polyvinly-chloride insulation, loaded by 70 mh inductances with a loading spacing of 1 km are given in Table 3. Type of cable (Loading system: L8 . 70 mh, S . 1 km) f kc mnep/ka OC radian/km Z ohm - ~+ Z cos (p ohm -Z sin ohm' [1] [2] [3] [4] [5] [6] [7] [8] 0.3 50.4 0.1704 910 16030' 883 258 FRVPY-0,8 ma 20W. 61.0 0.4561 865 8018' 850 125 2.4 100.8 1.4853 1092 5005? 1099 110 STAT Sanitized Copy Approved for Release 2011/05/19: CIA-RDP80-00809A000600120033-2 Sanitized Copy Approved for Release 2011/05/19: CIA-RDP80-00809A000600120033-2 0.8 mm diameter be laid over a route 6,810 m long. Dividing 6,810 by 1,000 we obtain 6.81. Consequently the number of spacings will be 7. Hence the length of the practical spacing will by 6,810: 7 - 973 m, and the length of half the spacing will be 973:2 = 487 in. Thus the outside coils should be installed at distances of 487 m from each of the stations and the intermedi- ate ones at a distance of 973 m from the outside coils and from each other. Deviations from the selected loading spacing, er;.uld mot oxcccd 2%- For example, if the loading spacing is one km, the coils should be installed not closer than 980 and not farther than 1,020 m from each other. neinre installing the inductance coil one checks that its lead-in wires conductors and between the coil windings and the cast-iron case is measured. If a cable with polyvinyl-chloride sheath is laid mechanically, pits measuring not less than 0.75 x 0.75 m and 0.7 -- 0.8 m c'aep are dug manually at the locations where the inductance coils are to be installed. The bottom of the pit is levelled and a recess is formed in it in such a way that the lead-in wires can be located on the bottom of the pit with a certain amount of slack (bend). Using the lead-in conductors, the inductance coil is connected in series with the wires of the loaded cable, paying particular attention to the thor- oughness with which the splices are made. The coil and the adjacent cable sections are then covered with a layer of sifted earth or sand not less than 10 cm thick and is protected against mechanical damage, by bricks, concrete slabs, boards impregnated with bitumen, etc. It is best to install the induction coil starting with any one station and using the following zequence. At the place where the first coil is in- cgtalled (at a distance of half a loading spacing from the station) the sec- tion of the cable is checked on the station side for open circuits and for grounds. Then a previously checked coil is inserted. After this one goes to the pit in which the second coil is to be installed (at a distance of one loading spacing from the first coil) and the section cable is checked from that point back to the station. If the checked section is in working order, the second coil is connected and the first pit is filled with earth or sand. The second pit is filled after checking the cable irom the third pit etc. It is also possible to perform the installation using 2 brigades work- ing simultaneously from both stations towards each other. However, no matter what method of organization is used, it is necessary that the route be measured and that the location of the coils be established beforehand, using a practical loading spacing previously chosen. If this condition is not satisfied, the length of the splice section may differ considerably (more than 2%) from the practical spacing; this will make it necessary to re- install the coils already installed. After completing the installation of the induction coils it is neces- sary to determine by electric measurements the insulation resistance, the d-c loop resistance, and the asymmetry of the loaded circuit. The document accompanying the cable should contain the following data: section in which the cable is laid, length of the section, type of cable, loading system and number of induction coil installed, date cable was laid. last name of persons installing the induction coil and results of electrical measurements. Sanitized Copy Approved for Release 2011/05/19: CIA-RDP80-00809A000600120033-2 STAT Sanitized Copy Approved for Release 2011/05/19: CIA-RDP80-00809A000600120033-2 STAT d.4nAQ75np U"-' 0.074%" 0 0 k?br+ki~llne~ $f75Mp,_ Qo7$n 4d75 bcffn.q +b,+ba+bA46q interurban telephone station of rayon central central telephone station intrarayon communication telephone substation intrarayon communication subscriber's telephone set line transformer Figure 1. Distribution of attenuation in intrarayon communication net. a, b, single-step construction of net; c, 2-step construction of set. SfL S S I ~y.~? ~ ~ Figure 2. Diagram of loaded cable line. Sanitized Copy Approved for Release 2011/05/19: CIA-RDP80-00809A000600120033-2 g07!lfMp C% g C17-4 4In-

Source URL: https://www.cia.gov/readingroom/document/cia-rdp80-00809a000600120033-2

Links
[1] https://www.cia.gov/readingroom/document-type/crest
[2] https://www.cia.gov/readingroom/collection/general-cia-records
[3] https://www.cia.gov/readingroom/docs/CIA-RDP80-00809A000600120033-2.pdf