From:
Fred Hopengarten, K1VR
Six Willarch Road * Lincoln, MA 01773-5105 * 617/259-0088
e-mail: k1vr@juno.com
Big antennas, high in the sky, are better than small ones, low.
On Tue, 7 Jan 1997 12:34:52 -0700 al511@freenet.uchsc.EDU (Robert Neece)
writes:
>I have read with interest the several postings concerning
>ascertainment of true north. I myself use a method different
>from those described so far.
>
>My method of indexing rotators, masts, and rotatable antennas to
>compass headings does not depend upon a determination of
>true north and, therefore, avoids compasses, clocks, calculations,
>sun shadows, and the like.
>
>I simply use a landmark of known (and constant) azimuth, and orient
>my antennas on the mast by sighting them against the landmark. Works
>wonderfully at the top of the tower, can be used on cloudy days, can
>be used at any time during daylight hours, and is fabulously accurate.
>
>In my own situation, a volcanic butte is visible near the
>horizon from the top of my tower. I obtained USGS 7.5 minute
>quadrangle
>maps that cover my QTH and the butte. (It takes two maps for me
>because the butte in question is on the quadrangle east of the one
>that
>contains my QTH.)
>
>An examination of the maps reveals that the butte is very nearly due
>east
>of my QTH. I calibrate the rotator indicator as described in the
>manual,
>and then set the rotator exactly at north. I then climb the tower and
>
>sight along the antenna element nearest the mast. With the
>boom-to-mast
>bracket somewhat loosened, I rotate the antenna on the mast until the
>element points straight at the butte. (With a yagi, of course, I
>position the antenna so that the reflector element is on the south
>side
>of the mast.)
>
>Tighten the boom-to-mast clamp. Perfect azimuth alignment
>automatically.
>
>This method is easiest to use if one can find a landmark at one of the
>principal compass points: N E S or W. A building, another tower,
>a geological feature, or anything else that is visible, and the
>location of which can be identified on the map, will work FB.
>
>Bob, K0KR and K7KU
Bob:
You are a smart fellow. I use a minor variation on your system.
I have determined with great accuracy that my three guy wires heading
"East" are at 110 degrees true.
I set my rotators to 110 degrees.
I climb the tower and make all rotary beam booms parallel with
those guy wires.
Even on the foggiest of days, when I cannot spot landmarks, I can
line up my booms with those guy wires.
Fred K1VR
--
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Submissions: towertalk@contesting.com
Administrative requests: towertalk-REQUEST@contesting.com
Problems: K7LXC@contesting.com
Sponsored by Akorn Access, Inc & KM9P
|