- Location
- In the islands
I am trying to get the compass to work properly. Who know the variance number for Iowa. I need to rein in this thing which seem to have a mind of its own. TIA
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Compass Variance
- Thread starter techno1154
- Start date
Jeepsloth
Gort like Jeep
- Location
- North Carolina
This should help, it is a link to a declination diagram for the entire US
http://www.ngdc.noaa.gov/seg/geomag/img/us_dec_8x11.pdf
http://www.ngdc.noaa.gov/seg/geomag/img/us_dec_8x11.pdf
Yucca-Man
NAXJA Member # 683
- Location
- Castle Rock, CO
Iowa's variance is going to be 7.
COMPASS VARIATION ADJUSTMENT
Variance is the difference between magnetic north and geographic north. In some areas, the difference between magnetic and geographic north is great enough to cause the compass to give false readings. If this problem occurs, the compass variance must be set.
To set the compass variance:
(1) Using the Variance Settings map, find your geographic location and note the zone number (Fig. 1).
(2) Turn the ignition switch to the On position.
(3) Depress both the US/Metric, and the Comp/Temp buttons. Hold the buttons down until “VAR” appears in the display module. This takes about five seconds.
(4) Release both of the buttons. The zone number will appear in the display module.
(5) Press and release the US/Metric button to step through the zone numbers, until the zone number for your area appears in the display.
(6) Press the Comp/Temp button to enter this zone number into the compass unit memory.
(7) Confirm that the correct directions are now indicated.
COMPASS VARIATION ADJUSTMENT
Variance is the difference between magnetic north and geographic north. In some areas, the difference between magnetic and geographic north is great enough to cause the compass to give false readings. If this problem occurs, the compass variance must be set.
To set the compass variance:
(1) Using the Variance Settings map, find your geographic location and note the zone number (Fig. 1).
(2) Turn the ignition switch to the On position.
(3) Depress both the US/Metric, and the Comp/Temp buttons. Hold the buttons down until “VAR” appears in the display module. This takes about five seconds.
(4) Release both of the buttons. The zone number will appear in the display module.
(5) Press and release the US/Metric button to step through the zone numbers, until the zone number for your area appears in the display.
(6) Press the Comp/Temp button to enter this zone number into the compass unit memory.
(7) Confirm that the correct directions are now indicated.
- Location
- In the islands
Yucca-Man said:
Thanks. This is exactly what I am looking for.
Yucca-Man
NAXJA Member # 683
- Location
- Castle Rock, CO
No problem - Iowa is pretty much smack-dab in the middle of the '7' band. However, parts of the western edge are in '6' if that helps.
Jim
Jim
RichP
NAXJA Forum User
- Location
- Effort, Pa
Isn't that compass supposed to be degaussed every so often, I remember reading about in the FSM and a discussion on it here a few years ago.
- Location
- In the islands
RichP said:
Looking back to posts quite some time ago you did mention de-gausing the compass. However, I do not have the means to do that. I just replaced one unit that would not come on with another from an '91 XJ but the compass is not showing the correct coordinates even after I reset the variance. I had a GPS magnectic mount antenna that I use for work connected to my PC sitting on the dash. I removed it and still the compass is off. In one direction it is about 45*, in another direction it would be 90*. I am not sure there is much I can do to trouble shoot it.
- Location
- Coshocton, OH
When I first installed the trip computer on mine it was off too even after setting the variance. After about a week or so I noticed it was reading correctly. I think it just needs some time to fully get it's barrings to where it needs to be.
RichP
NAXJA Forum User
- Location
- Effort, Pa
You can buy a hand held degaussing tool for like $15 or so, they were used for bulk erasing of mag tapes [vcr's, betas, etc] or you can make one too.
Did you drive around in circles to adjust it?
"The self-calibrating compass unit requires no adjusting in normal use. The only calibration that may prove necessary is to drive the vehicle in three complete circles, on level ground, in not less than 48 seconds. This will reorient the compass unit to its vehicle.
The compass unit also will compensate for magnetism the body of the vehicle may acquire during normal use. However, avoid placing anything magnetic
directly on the roof of the vehicle. Magnetic mounts for an antenna, a repair order hat, or a funeral procession flag can exceed the compensating ability of
the compass unit if placed on the roof panel. Magnetic bit drivers used on the fasteners that hold the assembly to the roof header can also affect compass
operation. If the vehicle roof should become magnetized, the demagnetizing and calibration procedures found in this group may be required to restore proper compass operation."
"The self-calibrating compass unit requires no adjusting in normal use. The only calibration that may prove necessary is to drive the vehicle in three complete circles, on level ground, in not less than 48 seconds. This will reorient the compass unit to its vehicle.
The compass unit also will compensate for magnetism the body of the vehicle may acquire during normal use. However, avoid placing anything magnetic
directly on the roof of the vehicle. Magnetic mounts for an antenna, a repair order hat, or a funeral procession flag can exceed the compensating ability of
the compass unit if placed on the roof panel. Magnetic bit drivers used on the fasteners that hold the assembly to the roof header can also affect compass
operation. If the vehicle roof should become magnetized, the demagnetizing and calibration procedures found in this group may be required to restore proper compass operation."
