[TowerTalk] aiming a rotor: true vs. magnetic
Wed, 11 Nov 1998 04:38:06 -0800
Gene, You are correct a lot of people go thru life trying to get the fly
S--- out of the black pepper. All you have to do is look at the plot of
the beam ,even a long monobander to see how wide the pattern is out
where you are trying to reach and it is say up to 30 degrees each side
of your target. Now if you were trying to land in the guys backyard in
Russia from Timbucktu you might need to have a ballistic computer.
Even the guy in Nevada with that fixed 1/4 mile long array pointed over
to Europe for 20M that was on the cover of QST has a lobe wide enough to
cover most of Europe. Have some more fly S--- I will loan you a 30X
glass so you can find it easier.
I thought this subject was TABOO on this reflector, as it was beaten to
death several months ago. If I remember Steve said NO MORE T--- N----.
Gene Ingraham, N2BIM wrote:
> Gee. Didn't we do this a few months ago? Tell me what HF beam has
> such a narrow bandwidth that a few degrees, one way or the other, will
> make one iota of difference? Personally, I use the North Star. It's
> close enough.
> 73, Gene...N2BIM..>>
> email@example.com wrote:
> > firstname.lastname@example.org 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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