xii METHODS OF COM MUNI CATION FOR FOREST PROTECTION 



Fig. Page 



46 Method of making entry to building from main line 93 



47 Wiring diagram of lookout station telephone set. 95 



48 Lookout station telephone set installed in the field 96 



49 Method of connecting lookout station telephone to line and ground 97 



50 Method of connecting howler ,and condenser 98 



51 Method of installing lavite coil to drain line of static electricity 99 



52 Method of installing a repeating coil on a pole 100 



53 Legend 101 



54 Switching station, first method 102 



55 Switching station, second method 102 



56 Wiring -and connections on 47^A repeating coil.. .... .. 103 



57 Phantom circuit 104 



58 Connecting grounded line to metallic line through a repeating coil without 



switches . . . 105 



59 Connecting grounded line to metallic line by use of switches and two 



telephones ..'.. .: . 105 



60 Connecting grounded line to metallic line by use of switches and one 



telephone . 106 



61 Method of using one wire for simultaneous telegraphy and telephony. . . . 107 



62 Forestry Branch portable telephone set (1375-A) 109 



63 Wiring diagram of Forestry B-ranch portable telephone ........ 110 



64 Adams hand set (1004-A) with carrying case Ill 



65 Wiring diagram of the Adams' hand set (1004-A) . . .'! . . . . Ill 



66 Forest officer preparing to use the Adams hand set with Cree knife 'for ground 



rod . . ..:..:.... . . .... . . . . 113 



67 Forestry Branch emergency communication kit No. 1-A. . .... ...... . . 114 



68 Wiring diagram of No. 1-A kit .. .. .. '. .. 115 



69 Forest ranger using the No. 1-A emergency kit '' '.'. . 116 



70 Bipolar hand receiver .!'.... .\! .. ..'.... 122 



71 Longitudinal section of bipolar .receiver.. .. .. .. .. ../.^.'. 122 



72 Diagram of telephone circuit, first stage .... .... . . .... 122 



73 Solid-back transmitter and transmitter arm. .'.' .. . . . . .'. . . . . . . 124 



74 Details of the solid-back transmitter '. . . . . . . 124 



75 Diagram of telephone circuit, second stage ". 124 



76 Telephone induction coil 126 



77 Diagram of telephone circuit, third stage. 1 . . 126 



78 Magneto generator, five-bar 127 



79 Polarized ringer, unbiased type 128 



80 Telephone switch-hook -''.V ".;. ' Ci :! .' . " '...' 130 



81 Rolled condenser . . . . . . . . 131 



82 Howler . . . . 132 



83 Lightning protector for use where there are no power ox light wires 133 



84 Protector with fuses for use where there .are power or light wires 134 



85 Baby knife-switches: (a) Single pole, single throw (S.P.S.T.) ; (b) Double 



pole, double throw (D.P.D.T.) 135 



86 Method of inserting a metallic circuit section in a grounded line to overcome 



induction disturbances 136 



87 Diagram of a phantom circuit . . . 136 



88 Telephones connected 1 in -.series on a metallic line . 138 



89 Telephones connected in series on a grounded line. 138 



90 Connecting bridging telephone on ,a grounded line 139 



91 Connecting bridging telephone on a metallic line.. 139 



92 Method of installing test station indoors 143 



93 Method of installing a' test station on a tree. . . . 144 



94 Stub reinforcement of poles 146 



