zeitler@ibm.net wrote:
>
> Esteemed Reflectees,
> I should remember this being an old Navy TACAN tech but........
>
> When aiming my rotor, I have my magnetic compass sitting right under the
> boom of my quad. Actually lying flat on the roof with the tower retracted so
> I can manually point the beam. I visually line up the boom with the compass.
> Okay so far. In order to aim the beam at "true" north I would actually want
> it pointing at 012 degrees if I have a magnetic correction of 12 degrees,
> right? of course the rotor also needs to be sitting at 12.
>
> Help!!
>
> Lane Zeitler
> KM3G
> IFF and TACAN tech
Hope I might be of some help. The easiest way to orient North is to use
a plumb bob - a lead sinker on a string will do fine - then go out at
night and eyeball the North Star through the mast and string. Put a mark
on the ground. Then in the daytime eyeball a line through your plumb
line and the two ends of the boom. You will be able to get this within a
few minutes of arc.
Not bad considering the divisions on the rotor indicator are 5 deg.
each.
I've found that by plumbing a long straight stick over my ground mark.
>From the top of the tower I can also eyeball through the mast, the end
of the boom and the stick to within a few minutes of arc.
Problem is magnetic North is subject to several variations including an
annual and a daily variation. It's not much, certainly less than a
division on the rotor dial, but it still exists.
73
Dave Hough, KC7DM
Las Vegas
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