Cobra II and Compas

I have the Cobra II computer with the built in compass. I like the computer well enough and have no complaints with it but the digital compass is completely useless. It requires to be within 3 degrees of horizontal to give any reading. Even after 40 dives in which I have greatly improved my buoyancy and can now hover with some moderate ease I spend way too much time trying to get a heading. I want to dive, not spend 2 minutes trying to get a heading and then swimming 15 feet before I need to spend another 2 minutes trying to check my heading.

So I want to get a regular old fashioned dependable analog compass. I had thought to purchase a compass that fits to the top of my Cobra II console. My LDS warned that having two compasses next to each could interfere with their readings. Is this ture. Will setting an electronic compass and a magnetic compass next to each other cause interference and inaccurate readings?

If putting the compass on the console is a no go what kind of compass would you recommend? Should I get a wrist mounted compass or a retractable compass?

Thanks!!

Jeremy

My 0.02 psi:

1) I hate the compass on my suunto D9 but love the computer...worn on right arm
2) the suunto sk7 on my left arm is the best compass i've ever worked with

there's some previous threads about multiple compasses and computers and interference like this one:

http://www.scubaboard.com/forums/co...nalyzers/12051-comp-interferes-w-compass.html

Cheers.

-J.-

jaymal:

So I want to get a regular old fashioned dependable analog compass. I had thought to purchase a compass that fits to the top of my Cobra II console. My LDS warned that having two compasses next to each could interfere with their readings. Is this true. Will setting an electronic compass and a magnetic compass next to each other cause interference and inaccurate readings?

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The Cobra2 will not interfere with the Suunto SK-7 magnetic compass that you can back-mount or end-mount on your Cobra2's console. I'm not sure whether the SK-7 will interfere with the Cobra2's sensor and render it unusable while the compass is attached, but as you've already found the Cobra2's compass to be irrelevant, that need not affect your decision.

Unlike an SK-7 magnetic compass, the sensor in the computer does not create a significant magnetic field. In fact, its smallness and sensitivity is the very reason why I would suspect it may be more likely to be affected by the magnetic field of a nice "real" compass.

Personally, I moved my magnetic compass *off* my console so that it would be easier to use for navigation, but having your compass on the console will not cause any adverse operation of the magnetic compass. I do not use the electronic compass in my Vyper2, however, I do appreciate that it is there in case I ever need it, even if it would be useful only for fixes and not so much for actual navigation.

ClayJar:

The Cobra2 will not interfere with the Suunto SK-7 magnetic compass that you can back-mount or end-mount on your Cobra2's console. I'm not sure whether the SK-7 will interfere with the Cobra2's sensor and render it unusable while the compass is attached, but as you've already found the Cobra2's compass to be irrelevant, that need not affect your decision.

Unlike an SK-7 magnetic compass, the sensor in the computer does not create a significant magnetic field. In fact, its smallness and sensitivity is the very reason why I would suspect it may be more likely to be affected by the magnetic field of a nice "real" compass.

Click to expand...

I myself have a cobra2 and yeah the computers digital compass actually goes 180 with a normal compass above it. Something strange I noticed was that i actually got a 3 degree difference in the magnetic compass when I pulled off my compass from my computer. However once the compass was off the computer for about 4 days I noticed there was no difference When I put the compass next to the computer. I am not sure if it charged some how or who knows what but 3 degrees can be a large difference. I was very careful to make sure i didnt move the position of the compass as I moved the computer around it to see if it effected the compass. Dont know maybe it was just a fluke. If you put a compass on the cobra2 definitely do not try to use the digital compass. The reason I got the compass was so that I would be able to try to get used to it while at the same time not getting lost. I was told the compasses would not effect each other by two different dive stores.

I don't much like the compass on my cobra II either, which was kind of disconcerting since that was the reason I bought it over the suunto cobra, live & learn huh,Iresolved the issue with a dial compass on a retractor, much better now.
Robert