Chapter 7 — COMMUNICATIONS EQUIPMENT AND OPERATIONAL PROCEDURES 



is easily accomplished by a simple hand opera- 

 tion by station personnel. The recorder is de- 

 signed to operate on either 60 or 120 scans 

 per minute. 



PRINCIPLES OF OPERATION. — The re- 

 corder has a helix drum which rotates syn- 

 chronously with a scanner at the sending point. 

 The paper passes between two electrodes; 

 one is a continuously moving blade in the 

 cover above the paper, and the other is a 

 resilient helix mounting on a rotating drum 

 underneath the paper (fig. 7-7). 



As the scanner sees the maps as an ON- 

 OFF signal, it causes current or no current 

 at any instant between the resilient helix and 

 the loop electrode. The resilient helix contact* 

 the loop electrode instantaneously at only on< 

 point which is constantly moving from left to 

 right. The paper passes between the helix and 

 the loop. There is an electro-chemical action 

 when current is flowing from the loop to the 

 helix which causes ions to leave the loop elec- 

 trode and plate the surface of the paper with 

 the markings. This spot, multiplied by ON- 

 OFF pulses, then produces the exact facsimile 

 of the map being transmitted. 



OPERATING INSTRUCTIONS. — The operating 

 instructions for the Alden 19 are as follows: 



1. Turning Recorder ON-OFF. Turn the re- 

 corder ON or OFF using the power switch lo- 

 cated on the left-hand side of the cabinet. Trigger 

 the manual start switch to start recording during 

 map signals. Observe the "no paper" indication 

 light; if the light is on, replace the paper. 

 The recorder shuts off at the end of the paper. 



2. Setting the Program Clock. Set the start 

 time to occur prior to the first map required. 

 Place the start pin in the inner ring of holes 

 adjacent to the desired start time. Set the stop time 

 to occur during the last required map. Place the 

 stop pin in the outside ring of holes adjacent to the 

 desired stop time. Put the pin in the day dial 

 for the day the recorder is to be OFF. 



3. Marking Amplifier Adjustment. To adjust 

 for best recording, turn the signal level control 

 clockwise from zero to the point where the 

 signal indicator begins flashing; turn the white 

 level control counterclockwise to the point where 

 the lightest map signal is still printing. Once 

 set, the automatic gain control compensates for 



FLYING 



SPOT 



CONTACT 



**► 



POSITIVE 



LOOP 



ELECTRODE 



PAPER FEED 



NEGATIVE 

 HELIX ELECTRODE 



ALFAX PAPER 



209.343 

 Figure 7-7. — Recorder operation of the Alden 

 Facsimile. 



all normal line level variations. NOTE: If the 

 signal level is set higher than necessary, it 

 reduces map sharpness. The white level over- 

 control removes a light signal. Both settings 

 for normal line conditions are 4, 



4. Automatic Paper Advance. With the AUTO- 

 MATIC FAST FEED switch in the ON position 

 it will advance the paper 6 inches at the end 

 of each map. The MANUAL FAST PAPER AD- 

 VANCE switch is located on the upper right- 

 hand side of the recorder case. NOTE: MARK- 

 ING SIGNAL TEST AND SIGNAL MONITOR 

 switches on the marking amplifier should be 

 to the left when recording. See the operating 

 manual for line level tests. 



To change the recorder speed while the 

 recorder is running, proceed as follows: 



1. Drum Motor. Set the selector switch to 

 either 60 or 120 rpm. 



2. Paper Feed. Press the manual start switch 

 on the auto rephase chassis and hold while press- 

 ing the 60 or 120 rpm feed button (upper right 

 side of the recorder head). 



To get the best results from this machine, 

 it is imperative the recorder be kept clean 

 and the helix and loop electrode be replaced before 

 they have worn so far that good copy cannot be 

 obtained. 



129 



