16 June 1999
12. Rotate turntable to 0, 90,180 270 degree headings.
Record Readout Error
at each heading in Table B.
13. Algebraically add the errors recorded at the four headings and divide by
four. This is the Index Error (I2). Record this value on line B-1.
Turn Power ON-OFF To Power OFF.
15. Corrected Magnetic bearing of the target (Bmag) is Bearing (B) of step
from 7 minus 1/2 of the quantity (Index Error of Step 6 (I1) minus Index Error
of Step 11 (I2)):
(I1) - (I2)
BMAG = B -
16. Disconnect cable W-2 from turntable and carefully remove the turntable
from the tripod. Replace it with the monitor and set up without moving the
tripod. Reconnect cable W-2 to monitor.
Turn Power ON-OFF to Power ON.
Adjust EXC volts to 23.5.
18. Sight target used in step 7 with monitor telescope and set azimuth scale
of monitor to bearing (BMAG) from line C-1.
19. Rotate monitor to a heading of 0 magnetic degrees, using azimuth scale,
and record readout error on console in line C-2. This is the system error.
The maximum allowable system error shall be 6'. If more than 6', reset
monitor by adjusting position of transmitter to 2' or better as read on
console. The error may be corrected by the following procedure:
To recalibrate monitor electrical versus scope, loosen setscrew and
adjust monitor transmitter position to near zero (electrical)
magnetic with respect to monitor scope as readout on console;
setscrew and adjust shaft are located at right side of compass
transmitter assembly on base of monitor.
Remove the cover plate from the monitor flux valve.
b. Sight a target at least 1/2 mile distant as near to magnetic north as
practical. Record console reading.
c. Invert the monitor telescope and resight the target. Record this
reading. Subtract 180 degrees. The difference between this reading and that
obtained in step b will be the amount of mechanical versus electrical error.
d. Return the telescope to its original position and resight the target.
Carefully loosen the flux valve mounting screws and adjust the valve until the