150 METHO'DS OF COMMUNICATION FOR FOREST PROTECTION 



Lightning-protectors should be inspected, and cleaned if necessary, after all electri- 

 cal storms. No. 60-E protector is cleaned by unscrewing the brass cap from the por- 

 celain base, removing the metal protector blocks, >and removing from them any soot 

 or smoke or pits which cause the blocks to touch each other. Both conditions are the 

 result of lightning jumping across the air gap provided by the mica sheet. In locali- 

 ties where lightning is particularly bad and the stations are difficult of access two 

 micas may be inserted between the blocks, thu increasing the width of the air gap. 



3 OILING GENERATOR 



Once every two or three years one drop of typewriter oil or "3 in 1" should be 

 placed in each of the places provided with oil cups. Great care should be taken to 

 see that no oil falls on any of the contacts or rubber bushings of the generator. 



4 ADJUSTMENT OF RINGERS 



(The following is from Telephone Circular, April, 1916, United States Forest 

 Service, District No. 5.) 



Ringers not in proper adjustment cause unsatisfactory signalling service. Not 

 infrequently an extension bell or ringer in a telephone is condemned as worthless, 

 when in fact it is merely in poor adjustment. When in proper adjustment either 

 gong, upon one-eighth turn of the generator crank, will transmit a high, clear tone 

 of the same sound. 



All bells connected to the same line should be of the same ringer resistance. 

 One ringer of different resistance on a line will seriously interfere with signalling. 

 Resistance of each ringer coil is usually marked 800, 1000, 1250, etc. A ringer having 

 two coils marked 1000 each has a resistance of 2000 ohms; two coils marked 1250 

 each indicate a resistance of 2500 ohms 1 . 



The ringers of -a new instrument are often thrown out of adjustment in transit. 

 When the telephone is installed the ringer should be tested and adjusted if necessary. 



(a) Adjustments. (1) If the ringer is loose on its base, remove the gongs and 

 tighten the screw which secures the ringer mounting. Replace the gongs and securely 

 tighten the gong screws. 



(2) Before commencing the adjustment, the instrument should occupy the posi- 

 tion in which it will be operated. If it is connected to a line, disconnect it. 



(3) If a coil spring should be found attached to the ringer, remove and discard it. 



(4) The base of the clapper rod (the armature) should have very little vertical 

 play. It should not be tight but should not wobble. It should be adjusted to move 

 freely on the pivots. In making this operation pay no attention to the sicfe movement 

 of the armature. To adjust, loosen the lock nut D (Fig. 96), then manipulate the 

 screw E until the proper adjustment is accomplished. Tighten or loosen to provide 

 just sufficient play in the armature pivots to be visible. 



With the screw-driver hold the screw in place, and with a pair of long-nosed 

 pliers tighten the lock nut. Care should be taken that the threads are not stripped 

 in this operation and that the screw does not turn. Only a slight pressure should be 

 applied to the lock nut. 



The gongs should next be so set that the clapper ball strikes but does not rest 

 against them when thrown from side to side. The space between the clapper ball 

 and one gong should be about %6 in. when the clapper ball is held against the other 

 gong. To change the positions of the gongs loosen the clamping screws B only 

 enough to allow the gongs to be moved by the turning of the eccentric adjusting 

 screws C until the correct position of the gongs is obtained. Let the clamping 

 screws remain loose until the stroke of the clapper is adjusted. To make this adjust- 

 ment turn the screw A to the right to shorten the stroke, and to the left to lengthen 

 it. Turn the generator handle only enough to cause the clapper to move toward one 



