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  #11  
Old 01-20-2011
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Birds falling, poles wandering...

FAA warns of ongoing GPS issues in southeastern US due to Defense Department 'tests' -- Engadget

"but anyone planning on using GPS in the southeastern US for the next month or so will likely want to make sure they have a fallback option. That's according to a flight advisory just issued by the FAA, which warns pilots that their GPS signal "may be unreliable or unavailable" due to "GPS tests" that the Department of Defense will be conducting between January 20th and February 22nd"
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Old 01-21-2011
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Renumbering runways is very common. However, its doesn't happen all that often since runway numbers are the closest tenth of their magnetic heading. ie 340 degs = runway 34. That also means that 337 degs = runway 34. Variation usually needs many years to move enough to round differently, but it happen all the time.

How often variation will alter, somewhat depends on where you are on the planet. Suffice it to say, that it moves slowly enough that even a chart that was fairly outdated, wouldn't be off by more than a couple of degrees. For coastal cruising, this is a non-issue. Crossing oceans can certainly be an issue.

The deviation of your compass is probably a more significant issue than variation. Each aircraft that I fly must have a deviation card attached to the compass, and it can read off by 5 degrees on some headings. We can also cross variation lines often on a single flight. In smaller planes, you must continually reset your heading indicator to your magnetic compass (for other reasons too, which I won't bore you with). In the larger planes that I fly, this is all slaved and resets automatically.
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Old 01-21-2011
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Quote:
Originally Posted by chrisncate View Post
Birds falling, poles wandering...

FAA warns of ongoing GPS issues in southeastern US due to Defense Department 'tests' -- Engadget

"but anyone planning on using GPS in the southeastern US for the next month or so will likely want to make sure they have a fallback option. That's according to a flight advisory just issued by the FAA, which warns pilots that their GPS signal "may be unreliable or unavailable" due to "GPS tests" that the Department of Defense will be conducting between January 20th and February 22nd"
Good point to note on thread about Celestial Navigation!-when I bought my first handheld Magellan GPS back in 1994 it clearly stated that US gov. could switch off the system at any time if it so chose.
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Old 01-21-2011
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The magnetic pole shifts all the time-if you examine the fine oblong crystals in some volnanic rocks they formed pointing north south at the time the rock solidified millions of years ago..
Here in UK we are very aware of the change-is that because being almost 58 degrees north it has a more pronounced effect on my compass or is it that no one uses compasses any more?
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Old 01-21-2011
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the north star also changes position , relative to the earth, but over a long time period. we wont notice it during our lifetime so we don't have to correct more than a degree for SN at sea.
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Old 01-21-2011
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Originally Posted by captbillc View Post
the north star also changes position , relative to the earth, but over a long time period. we wont notice it during our lifetime so we don't have to correct more than a degree for SN at sea.
Here is another explanation of this. Pole star - Wikipedia, the free encyclopedia
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Old 01-21-2011
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Quote:
Originally Posted by chrisncate View Post
Birds falling, poles wandering...

FAA warns of ongoing GPS issues in southeastern US due to Defense Department 'tests' -- Engadget

"but anyone planning on using GPS in the southeastern US for the next month or so will likely want to make sure they have a fallback option. That's according to a flight advisory just issued by the FAA, which warns pilots that their GPS signal "may be unreliable or unavailable" due to "GPS tests" that the Department of Defense will be conducting between January 20th and February 22nd"
Originally Posted by Boasun; from Navigating with GPS and Other Means thread.

The satellites will not be falling out of the sky, they are 11000 miles above the earth. But a major solar flare, a large dither put back in by the military, or jamming by those are enemies or those who think of it is a practical joke. Certain electronic equipement have jammed ship board GPS's.
Plus you may have not plugged in the correct chart datum. Or position the GPS antenna in the optimum position on your vessel. Bad antenna connection have caused one cruise ship to run aground. And I've had three GPS's go belly up on me, which is a good reason to have all of your way points listed in your Navigation work book AND use secondary means of Navigation to confirm your position.

The above is excellent reasons to practice Coastal piloting and maybe Celestial.
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Old 01-25-2011
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Ok dont shoot the messager plz...
Alarming NOAA Data Supports Observations of North Pole's Rapid Shift :

Alarming NOAA Data Supports Observations of North Pole's Rapid Shift -- Earth Changes -- Sott.net

I know it's an exteream site but good data ,there is a lot more there if you look around

I will be "playing" with Celestial until I get a real sextant gonna have to get by with a used Mark 25 , But I did buy a new watch just for this
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