On 10 Feb 2003 at 22:51, Bill Axelrod wrote:
> We used to use "East is least, West is best"
Nobody has allowed for the fact that the compass itself isn't perfect! It has
some
"deviation" from the correct direction,and that usually depends on the
indicated
direction. Here's the full story... (way more than anybody wants to know! I
could
always get these problems right in the classroom, but under stress at
navigating a
vessel or aircraft it's less easy!)
starting with the true bearing
"True virtue makes dull company. Add whiskey."
true+variation=magnetic+deviation=compass
The plus signs are used for westerly changes ("add whiskey" get it?) If the
compass
deviation or the local variation are EASTERLY, then use a minus sign.
starting with the compass bearing
"Can dead men vote twice at elections?"
compass+deviation=magnetic+variation=true
The plus sign is used for easterly changes ("at elections.") If the variation
or the
deviation are WESTERLY, then use a minus sign.
I, for one, am very happy that an antenna pattern in the contiguous 48 states
pretty
much washes all of these errors out!!
73,
approx 38N, 122W, variation about 15 degrees easterly
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