TM 11-4920-292-15
the remote magnetic compensator N-S control
one-half the initial error; for example, if the
until the heading indication changes by an
digital controller indicates 180.6, adjust the
amount equal to and opposite the computed
N-S compensator control until the digital con-
N-S error.
troller indicates 180.3.
(e) Set the HEADING SELECTOR
(o) Tighten the compensator N-S con-
switch to 90 DEGREES.
trol locking nut and check to see that the digital
controller heading indication does not change.
(f) Adjust the remote magnetic com-
pensator E-W compensator control to obtain
(p) Compute the E-W error by alge-
a 900 heading on the digital controller.
braically subtracting the error at 270 from the
(g) Set the HEADING SELECTOR
error at 900 and dividing the result by 2. Set
switch to 270 DEGREES.
the HEADING SELECTOR switch to 90 DE-
(h) Adjust the remote magnetic com-
GREES. Remove the E-W error by adjusting
pensator E-W compensator control to remove
the remote magnetic compensator E-W control
one-half the initial error; for example, if the
until the heading indication changes by an
digital controller indicates 269.3, adjust the
amount equal to and opposite the computed
E-W compensator control until the digital con-
E-W error.
troller indicates 269.65.
(g) Tighten the compensator E-W con-
(i) Set the HEADING SELECTOR
trol locking nut and check to see that the digital
switch to O, 90, 180, and 270 DEGREES. Record
controller heading indication does not change.
errors indicated by the digital controller at each
(r) Set the HEADING SELECTOR
heading in table F1 of the swing data sheet.
switch to 0, 90, 180, and 270 DEGREES. Record
errors indicated by the digital controller at each
NOTE
heading in table F1 of the swing data sheet,
If the digital controller indication is
(s) Error at 0 shall equal error at 180,
greater than the HEADING SELEC-
and error at 900 shall equal error at 270 within
TOR switch setting, the error is posi-
0.2 degree.
tive; if it is less, the error is negative,
(4) Determine transmission (two-cycle)
(j) Determine the index error by adding
the four errors algebraically and dividing the
(two cycle) error as follows:
sum by 4,
(a) Set the HEADING SELECTOR
(k) Set the HEADING SELECTOR
switch to 0, 45, 90, 135, 180, 225, 270, and 315
switch to 0 DEGREES, Remove the index
DEGREES. Record errors indicated by digital
error by turning the remote magnetic com-
controller at each heading in table F2 of the
pensator INDEX knob until the heading indi-
swing data sheet,
cation changes by an amount equal to and op-
(b) Compute the D and E coefficients
posite the index error.
as follows:
(l) Tighten the remote magnetic com-
pensator INDEX control locking screw and
check to see that the digital controller heading
(c) Graphically determine the magni-
indication does not change,
tude and direction of the error coefficient. (Re-
(m) Set the HEADING SELECTOR
fer to graph in figure 9-21.)
switch to 0, 90, 180, and 270 DEGREES. Record
errors indicated by the digital controller at
(d) Draw a horizontal line between the
each heading in table F1 of the swing data
D and D' scales at the calculated value of the
sheet.
D coefficient, and draw a vertical line between
the E and E' scales at the calculated value of
(n) Compute the N-S error by alge-
the E coefficient; then draw a line from the
braically subtracting the error at 1800 from the
error at 00 and dividing the results by 2. Set
center of the figure through the intersection of
these lines. This line determines the magnitude
the HEADING SELECTOR switch to 0 DE-
and direction of the transmission error.
GREES. Remove the N-S error by adjusting
9-26
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