#149695 - 09/20/08 04:01 PM
Re: Best Survival Compass
[Re: Chris Kavanaugh]
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Journeyman
Registered: 05/26/06
Posts: 77
Loc: Cochise Co., AZ
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A drafting compass and, I'm guessing, a Radio Compass (RDF)?
Pat
Edited by PSM (09/20/08 04:02 PM)
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#149697 - 09/20/08 05:05 PM
Re: Best Survival Compass
[Re: Am_Fear_Liath_Mor]
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"Be Prepared"
Pooh-Bah
Registered: 06/26/04
Posts: 2211
Loc: NE Wisconsin
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Once again, do keep in mind that since 1969, to get a real Silva of Sweden compass in the U.S. you'll need to look for the Brunton or Nexus labels, since those sold under the "Silva" label are NOT made by Silva of Sweden.
If I were very close to the north pole - with Santa - I would think that a regular compass wouldn't point north. Yeah, I know, I'm stretching it.
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#149698 - 09/20/08 05:10 PM
Re: Best Survival Compass
[Re: colbyhouse]
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Geezer
Registered: 06/02/06
Posts: 5357
Loc: SOCAL
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GPS receivers are great, but good navigation skills start with understanding the basics -- map and compass. A number of different compasses can serve you well. The Compass Store is a good place to find many options. My favorite user is the Suunto M-2G. IMO it's their "Best Pick" for good reason. Once you have whichever compass you select, learn to use it in conjunction with a map (topo, street, whatever) to stay found. Refinding yourself after getting lost is not always as easy as you may think, even with knowledge of map and compass.
_________________________
Better is the Enemy of Good Enough. Okay, what’s your point??
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#149699 - 09/20/08 05:26 PM
Re: Best Survival Compass
[Re: Travis]
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Carpal Tunnel
Registered: 11/09/06
Posts: 2851
Loc: La-USA
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I don't mean to possibly "sound" rude but some clarification is obviously needed:
"Variation": The difference between True North and Magnetic North.
Usually expressed in degrees & minutes, and labeled East or West; to be added or subtracted from the True North direction, as mapped/charted. Usually found within the Compass Rose and along the mapped Variation lines. There are annual additions or subtractions that must be made between the chart edition year and the year that you are using the map/chart. Use the following guides for converting to/from True North to Magnetic North:
Timid Virgins Make Dull Companions At Weddings (true) (variation)(magnetic) (deviation) (compass) (add west) 000T + 2w = 002 - 2e = 000M
Can Dead Men Vote Twice And Eat (compass)(deviation) (magnetic) (variation) (true)(add East) 000M + 2e = 002M - 2w = 002T
Deviation: Is the measured magnetic (usually steel construction) influence of an object (such as a ship) upon the magnetic flow around it. Ships are required to "swing compass" after shipyard work, gunfire, welding/cutting ops, and annually. Taking Deviation into effect on a vessel is necessary, but not for a hiker/backpacker trying to navigate. In the rhymes above, the hiker/backpacker would skip the deviation/magnetic parts to make the following:
Timid Virgins Make At Weddings
Can Vote Twice And Eat
Declination is a factor used in Celestial Navigation of all types. It is not a factor in terrestrial navigation using only a magnetic compass and map/chart.
Lagniappe Item: The difference between a chart and a map: Maps are made to look at! Charts are made to be worked upon!
_________________________
QMC, USCG (Ret) The best luck is what you make yourself!
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#149700 - 09/20/08 05:28 PM
Re: Best Survival Compass
[Re: wildman800]
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Member
Registered: 02/22/08
Posts: 103
Loc: SE Alaska
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In spite of all the expensive stuff I have around, I keep using a Brunton 9020G. 12 bucks...go figure....
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#149703 - 09/20/08 06:34 PM
Re: Best Survival Compass
[Re: DannyL]
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"Be Prepared"
Pooh-Bah
Registered: 06/26/04
Posts: 2211
Loc: NE Wisconsin
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I too often use a Brunton 9020G - it fits very nicely in my pants pocket.
The only concern I have with it is related to its symmetric shape. I've seen Scouts use it backwards. They use the end opposite of the direction of travel arrow by mistake.
Actually, if they used the same end all the time it wouldn't matter, but I've seen them switch between ends, which sends them in the wrong direction.
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#149704 - 09/20/08 06:40 PM
Re: Best Survival Compass
[Re: KenK]
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Member
Registered: 02/22/08
Posts: 103
Loc: SE Alaska
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well, if they're not gonna put a lanyard on it, train them that just like their bodies, the hole in the end points south.
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#149706 - 09/20/08 06:47 PM
Re: Best Survival Compass
[Re: KenK]
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"Be Prepared"
Pooh-Bah
Registered: 06/26/04
Posts: 2211
Loc: NE Wisconsin
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I'm no expert in the navigation terminology, but ... NOAA's Geomagnetism web site Magnetic Calculator Help page ... http://www.ngdc.noaa.gov/geomagmodels/MagneticCalculatorFAQ.jsp?pagetype=0#help8...defines Declination as "the angle of difference between true North and magnetic North. For instance, if the declination at a certain point were 10° W, then a compass at that location pointing north (magnetic) would actually align 10° W of true North. True North would be 10° E relative to the magnetic North direction given by the compass." I prefer a compass that has true adjustable declination. ...defines Inclination as "the angle between the magnetic field vector and the horizontal plane (the plane is tangent to the surface of the Earth at that point). The inclination is positive when the magnetic field points downward into the earth and negative when it points upward." Compasses are sold based upon the global region that they will be used in. Here is a site with a map of those regions: http://www.wide-screen.com/support/FAQsuunto.shtml#Anchor-60059Suunto's global needle is specially designed to self-adjust for differences in inclination, so it can be used in any (?) of those regions.
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#149707 - 09/20/08 06:53 PM
Re: Best Survival Compass
[Re: DannyL]
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"Be Prepared"
Pooh-Bah
Registered: 06/26/04
Posts: 2211
Loc: NE Wisconsin
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well, if they're not gonna put a lanyard on it, train them that just like their bodies, the hole in the end points south. I was taught to put a lanyard on my compasses - and alway do, but many (most) Scouts don't bother regardless of what they're taught - I think partially because their t-shirts don't have breast pockets for stowing the compass - so they use their pants pockets - and don't like the lanyard wrapped up on the pocket. Of course, if you check with the average Scout today, they don't even carry a knife. Sigh.
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