Magnetic variation

oops 11.3

Mike,

I meant to add, get a look at a chart of Port Phillip Bay it will have the variation in the compass rose on the chart.

I love your rig Reg that would have to be a real adventure doing it that way, good on you!!

Have you checked out my camper in my Profile.
I think it shows you dont need much to have a great time in our Australian outback.

Yes I did notice your camper. Good thing about your rig is you don't have to worry about the best tyre to get, don't have to worry about sidewall punctures or getting bogged!!!

I would've thought to align the antenna to 'true' not 'magnetic' ..

he needs to subtract/add the magnetic deviation.
if a target was 180 from his position on the map, and using a compass to find this heading, the reading would be 11 degrees out because of the magnetic deviation in that area.
your gps can probably be set for true or magnetic.
ozie CE can display the local deviation if reqd, which i find handy.

Be careful here howie....Don't want to start an arguement but..
There is a difference between magnetic deviation and variation..

Signman:
Judging from your original post I'd say you have been doing an internet search (Wikipedia) and have next to no idea what you're talking about.

Mike Harding

no worries signman, i do know the difference, it was a slip of the keyboard.
i use an adjustable compass that i calibrate for deviation.
ozieCE incorrectly has "mag dev" as default, which i have changed to "mag var"
and in a small experiment (OK i'm bored) using a small crappy compass, placing it near objects.
computer screen - 40 degrees out
mobile phone - 60 degrees out
bluetooth GPS - an ironic 120 degrees out
be careful with your compasses people.

I have fond memories watching a bunch of sailors working out where they were at a track intersection in the Gembrook state forrest with a map and compass.

They had the variation worked out and were orienting the map to north - on the bonnet of a land cruiser. I (the instructor) questioned this but some bright spark told me that it was all OK - the bonnet is aluminium and non-magnetic.

He was so happy with this answer I chose not to enlighten him about the effect a V8 motor just inder the bonnet would have on the deviation (about 90 degrees in this case). We all took off up the wrong track and they got themselves (but not me) seriously lost.

The really hilariious bit was they they had stopped under a sign with both tracks posted! The exercise debrief an hour later was a lot of fun.

Cheers

Pete