# [TowerTalk] True North vs. Magnetic

Pat Barthelow aa6eg@cv.tmx.com
Mon, 30 Mar 1998 13:53:25 -0800 (PST)

```HI Paul,

Yes, the difference beteen true and magnetic north where I am, (Marina CA,
near Monterey) is 16.5 degrees.  True north is counterclockwise from
magnetic north, by this amount.  It is different in San Francisco, but by
such a small amount when pointing HF Yagis, as to be insignificant.  So,
if
you consider a compass rose as reading degrees from zero to 359,
clockwise (360 would
be zero again) then you would find true north was at 360 minus 16, or 344
degrees.....IF you align the 0 degree marker with the north pointing
needle of the compass.  To say the same thing another way, put the north
needle of the compass on the 16.5 degree mark, and then the 0 marker would
be on true north.  As a check, you might look at a map of your local town.
if the streets are largely rectangularly oriented (at right angles to
each other, then chances are, they are very close to True North/South, and
East West.  (San Francisco for example has N/S, E/W oriented streets...
Remember, that Most HF amateur beams are so broad patterned, that an error
of 10 degrees either way would not even be noticed....

Good Luck and good DX.......BTW, if you want a great circle map done for
you, there are a number of places on the internet that will create one to
your specifications...Use a serch word of NV3Z, on Alta Vista and get a
server there to make you a custom Great Circle Map....

73, DX de Pat, AA6EG/N6IJ "The Contest Station from the Government"

Marina Amateur Radio Contest Station; N6IJ
599 DX Drive
Marina CA 93933

aa6eg@tmx.com

On Sun, 29 Mar 1998, Paul Booth wrote:

> Perhaps this is the wrong place for this question, but I'm about to put
> up my first Tribander.  I understand that there is a difference between
> magnetic north and true north.  Can anyone tell me how much (and
> direction) of correction I should adjust to from magnetic north?  I live
> in the San Francisco Bay area.  Thanks.
>
> 73s de WA6IBU, Paul
>
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