TM 11-4920-292-15
NOTE
NOTE
If a null cannot be obtained using the
Set this value on the MISAL MIN-
El VOLTS vernier control, the com-
UTES switch (to the nearest 3-minute
pass transmitter probably is out of
position). Set the MISAL polarity
tolerance.
switch to the sign ( + or ).
(4) Set the MODE SELECTOR switch to
(17) Repeat the procedures given in (16)
CAL.
above twice, tapping the compass transmitter
lightly before each null.
(5) Tap the compass transmitter lightly.
(18) Add the six settings recorded in table
(6) Set HEADING SELECTOR switch to
C2 of the swing data sheet and divide the sum
0, 90, 180, and 270 DEGREES, Record the
by 6, Set the E1 VOLTS controls to this aver-
ERROR readout indication at each heading in
age value and record the value on line C-2 of
table D of the swing data sheet,
the swing data sheet.
(7) Repeat the procedures given in (5)
(19) Set the control console switches as
and (6) above twice.
follows:
(8) Algebraically add the three errors at
(a) AREA COMP to setting recorded
each heading and divide each sum by 3. Record
on line A-6 of the swing data sheet.
the average errors in table D of the swing data
(b) E2 NORM.-E2 REV.: E2 NORM.
sheet.
(c) HEADING SELECTOR: 0 DE-
(9) Record the corrected manual swing
GREES.
errors (table B) in table D of the swing data
(d) MODE SELECTOR : MON.
sheet.
(e) E1 CHECK-E2 CHECK: E1
(10) Algebraically subtract the corrected
CHECK.
manual swing errors from the average electrical
(20) Adjust the E1 CHECK vernier until
swing errors (table D) and record in E-M
the NULL INDICATOR meter indicates a null.
column of table D of the swing data sheet;
Record the vernier setting on line C-3 of the
resultant values shall be as follows:
swing data sheet.
(a) The E-M values at each cardinal
(21) Set the E1 CHECK-E2 CHECK
heading shall
switch to E2 CHECK.
1. not exceed:
(22) Adjust the E2 CHECK vernier until
2. At 0: 5 minutes.
the NULL INDICATOR meter indicates a null.
3. At 90: 30 minutes.
Record the vernier setting on line C-4 of the
4. At 180: 60 minutes.
swing data sheet.
5. At 270: 30 minutes,
d. Determine ∆ 180 MINUTES and ∆ 270
(b) The E-M value at 90 minus the
MINUTES and polarity values as follows:
E-M value at 270 shall be 9 minutes, or less;
(1) Set the control console switches as
if it is not, recheck calculations given in table B
follows :
of the swing data sheet and repeat the compass
transmitter calibration procedure (c above).
(a) READOUT SELECT: F.V.
(11) The ∆ 180 crosstalk error is the
(b) E1 CHECK-E2 CHECK: OFF,
(2) Record the ERROR readout indication
E-M value at 1800. Record this value on line
D-3 of the swing data sheet. Set the ∆ 180
as monitor zero error on line D-1 of the swing
data sheet.
MINUTES switch to the nearest 3-minute posi-
tion, and the ∆ 180 polarity switch to the sign
(3) Using the swing data sheet, calculate
( + or ) of the error.
the misalignment value as the algebraic sum
(12) Calculate the ∆ 270 crosstalk error
of transmitter index error (line B-1) plus moni-
tor zero error (line D-1) minus monitor zero
as the algebraic sum of the E-M value at 900
error (line B-2). Record the value on line D-2
plus the E-M value at 2700. Record this value
on line D-4 of the swing data sheet. Set the ∆
of the swing data sheet.
9-10
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