True North in one sentence

Bill Hider n3rr at
Sat Nov 2 00:26:20 EST 1996

k4sb at wrote:
> No, that isn't so unless you live exactly on a longitude which seperates
> 2 time zones, or if you live exactly on the spot where the data is
> referenced, which is unlikely because most of it is referenced to an
> airport, with exceptions.. You must adjust your Local Apparent Noon by
> adding the degrees and seconds to the longitude and coming up with your
> true noon time. Obviously, shadows in Savannah, GA pointing due north do
> not coincide with those in Atlanta.
> Good idea though, however I fail to understand why everyone just doesn't
> use the North Star. It's easy to see, and directly true north.
> However, it all seems an exercise in futility since most beam heading are
> derived using a Mercator projection, ( which is distorted ) and thereby
> issue magnetic headings, which must be adjusted for East/West deviation.
> Ed
> -------------------------------------
> Name: ed sleight
> E-mail: k4sb at
> Date: 11/1/96
> Time: 11:51:23 AM
> This message was sent by Chameleon
> -------------------------------------
Ed, I said at the half way mark between your local sunrise and
sunset..That implies that if you live far from the location that you
know the sunrise and sunset you must get "your" local sunrise/sunset. 
In actuality, it's not that far off if you live within 30 - 50 miles
from the datum airport, etc.  The use of this data, I have assumed, is
for aligning contest beams which have 3 dB beamwidths of >45-50 DEG!

And most headings I use for contests are not taken off mercator
projections.  They are taken off LAT/LON data which is very accurate.

Why would anyone use sunrise/sunset for Atlanta if they live in
Savannah?  I did say "LOCAL" sunrise/sunset.



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