Boundary Waters Quetico Forum :: Gear Forum :: My 2 compass disagree
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jwartman59 |
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mschi772 |
mjmkjun: "How about returning both and purchasing just one reliable compass. (raving reviews are helpful here)" Thing is: The Suunto MC2 is considered to be a good compass. |
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RLJ |
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RLJ |
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Wick |
i took them to work with me to play more and ship them out.My partner messed with them and came to the same conclusion, they differ by 7-8 degrees. He is younger and has better eyes! We went upon the roof to look at maint that needed done. I took the compasses with me to do some sighting of far away objects to see what the distance would look like between the two at the 7-8 degree off, pointing to the same degree. As i got to the top, i pulled theout of my pocket, threw one to him to play with,,completely missed him,,,and watched the compass bounce off the man ladder 2 or 3 times on the way down, bounce off the elect service, then hit the asphalt. About 30-35 ft. My partner laughed and said, i hope that was the bad one! I went down and picked it up. Not even a scratch on it. Now the best or worse part, i can’t decide,,,,,,,they read exactly the same now. I do not understand this at all,,,, |
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Wick |
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Savage Voyageur |
Could it be that the one you dropped off the roof was the faulty reading one? Could it be that the compass needle that moves was not in the correct spot on the stationary pin to begin with? Could it be that the drop somehow knocked the needle into the correct place? |
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boonie |
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butthead |
Wick: "So how much should i charge for fixing compasses for you guys? Really, i guess i could do it for free, but i am semi scared of heights,,and it isn’t a great time for me when i have to go up on the roof. " May I interest you in a piece of company startup equipment for your new vocation, compass adjusting tool May save time in production and improve safety! butthead PS: Ooopps, need to edit, misspelled piece, of course it's immortalized in Wick's response. bh |
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Wick |
How would i tell which one is wrong? |
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Northwoodsman |
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andym |
Also, be careful that you aren't moving some piece of metal near them such as a belt buckle. |
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Wick |
Savage Voyageur: This is what both of us thought. My partner hd mentioned before that he thought one compass needle did not move as freely and quickly as the other. When i went down to get it, i expected the needle to be diconnected, laying off to the side with liquid gone,,,ect. We looked at it under magnifying glass, did not see a piece of dirt dislodged or anything like that. |
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mjmkjun |
Wick: "So how much should i charge for fixing compasses for you guys? Really, i guess i could do it for free, but i am semi scared of heights,,and it isn’t a great time for me when i have to go up on the roof. " Bwaaa hahaha You have a Wicked sense of humor, dude. |
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billconner |
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Wick |
butthead: "Wick: "So how much should i charge for fixing compasses for you guys? Really, i guess i could do it for free, but i am semi scared of heights,,and it isn’t a great time for me when i have to go up on the roof. " That would keep me from climbng,,but would raise prices,,high tech and all that. |
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andym |
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drnatus |
billconner: "Sounds like tates compasses." I get that reference! |
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WIMike |
andym: "Good idea about the local airport. That's great if they have an accurate compass rose. How accurate are the runway orientations? Don't they often give them just to the 10 degrees?" Airport runways are labeled in 10 degree increments. ex. Rwy 27 could have a heading of anywhere from 265-275, can’t remember whether the 5s go to next higher or next lower. The exact runway heading is displayed on airport diagrams accessible by the public though. Ask at the airport and they can tell you an exact runway heading. |
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24kGold |
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Wick |
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old_salt |
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gymcoachdon |
butthead: "I don't think any side by side simultaneous comparison is accurate. Too much variable interference. If I put all my compasses on a table they all read different. That is a great answer. I always listen to butthead... |
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Wick |
andym: "Also, are you testing them by putting them next to each other? Or separately, by taking the orientation of the same point on a table? The latter is a better idea as they can affect each other. I have tested them everywhere. I put them on coffe table with a brand new phone book between them so the edges are parallel, and they are approx 11 inches apart. The bezels are lined up with north and south. No matter how i position everything, they read from 7-10 degrees different. |
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Savage Voyageur |
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Ausable |
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ParkerMag |
Seems odd to me, but I'm not a compass nut. I subscribe to the "close enough" school of thought too. |
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thebotanyguy |
Now, how does one determine which one is inaccurate? Perhaps you have a straight stretch of road nearby that runs north/south. Take a bearing down the road to determine accuracy of your compasses, taking the declination into consideration of course. |
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andym |
If it is clear that one is bad, I agree with going outside and using a long straight road to see which one is off. Or call a geologist at a local university and ask if you can test against their compass. They probably have a brunton pocket transit which is very high quality. Or call a surveyor. Yes, 7 degrees isn’t a big problem for navigating but I would still return the bad one. But then, I use my compass for work and 7 degrees off on lots of observations just isn’t worth dealing with. |
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butthead |
Take one out and check the bearing to a distant object. Then check the other independently, same compass position same distant object. Even then if they disagree it's consistency for the individual compass that is important. As long a each constantly indicates the same repeatably, you can adjust for that. Unless you expect to do some technical orienteering or triangulating compass exercises, navigation is sort of like horseshoes, close is often good enough. butthead |
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drnatus |
butthead: "I don't think any side by side simultaneous comparison is accurate. Too much variable interference. If I put all my compasses on a table they all read different. don't disagree with any of the above, but there is something disconcerting about this. |
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Northwoodsman |
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Blatz |
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Wick |
I will try the airport. Andym, yes, i switched positions every place i tried them and the results followed the compass. I had the kitchen table baffling me for a while until i saw it had a metal expansion rail under it to add leaves to the table. I can get completely away from metal, outside, and the error does not change. i just bought a new gps too. I will see if i can find a way to check with that tonite. These things are too expensive to be that far off! |
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Huntindave |
Wick: "I bought 2 brand new compass, one for each canoe. They are both suunto mc-2 NH USGS. They disagree by about 7 degrees! They may both be off BUT you can correct that so they will both be dead on. The quality control for this compass is 2.5 degrees. The two could be 5 degrees different and still be within the quality control specs for the product. You can adjust these so they are both dead on. Any compass that is adjustable for declination can be made to read dead on. for example; if your compass is pointing dead on the magnetic north and the area your in has 12 degrees declination error, one would adjust the compass by 12 degrees. However if your compass is pointing 3 degrees off from magnetic north then just adjust for declination by either 9 degrees or 15 degrees (dependent on the direction the 3 degree error is) After this correction is done for both compasses, you can use them without regard to which one you have in you hand at the time. Below is a review taken from the Suunto web site; Good, except for declination accuracy. As a volunteer with The Mountaineers, and Seattle Mountain Rescue, we see this compass being used all the time. Some percentage of them have the declination scale offset about 2 degrees from the degrees scale on the bezel. For example, we set it to 16 East for Seattle, but find that we are always 2 degrees low at a calibrated compass check station that we use. We change them to 18 degrees East and the compass then measures the bearing accurately." |
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mjmkjun |
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andym |
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boonie |
I'd still want my compass to be more accurate than 10 degrees though. Besides the methods already offered, if you can find the Pole Star, you could take readings on it. |
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butthead |
butthead |
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andym |
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cowdoc |
Wick: "i can put up with a degree or maybe two,,,but 7-10 is too much. I believe I can point my finger more accurately then that! LOL,,,maybe. Lucky you didnt buy 2 new GPS units...... |