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Raymarine GPS navigation User Manual

Page 64

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Type in the numeric value 1, 2 and

In our example the

correction was a plus value. So, even though the

prompt just came

on-screen, just press

again for the

TD 1 correction.

pressed, the display

i s n o w r e a d y t o c o n t i n u e w i t h e n t e r i n g

the offset value for TD2. Type in the numeric value

T

h

i

s

time press the

since the correction was a minus value. Then press

store the

TD2 value.

Manual L/L Corrections

Instead of using the Auto ASF program or the manual TD offset values, the

coordinates may be corrected manually. The process is similar to making

manual TD correction entries, and is accomplished in the following manner:

First go to a fixed navigation point and read your current L/L position

the loran display. Extract the L/L coordinates of the fixed point

your

marine chart. Subtract the two Latitudes and the two Longitudes from each
other to determine the appropriate correction to be entered into the

NAV

unit.

Example: N42 42.23’ Loran

W071 24.54’ Loran

N42 42.08’ Chart

Chart

.

(South)

(East)

After you have calculated your correction, select the

POSITION CORR

.

menu. Press the

to highlight

.

Type in the value of Latitude Offset 1, 2, 6. Press

key.

appears at the center

position. Since our sample offset is to the South,

press

to change the direction for the latitude correction to

pressed, the display will expect you to enter the value of

the Longitude Offset with the numeric keys. Type in 1,

Press

and the “E/W” characters appear again at the center

position. This

time the correction is to be subtracted. Use

key to select E (-) for

the longitude correction before pressing

Press

to return back to the Main Menu Directory. You could

more time to go back to the display mode. However, this

time press

again

so we cm

check the

AVERAGING

menu for Loran.