[TowerTalk] Laying out antennas

[Kevin Hemsley]

If all you have is a Boy Scout compass, you can find true North if you know
what the variation is between true and magnetic North. For those who haven't
found this page yet, magnetic declination, sometimes referred to as magnetic
variation can be calculated here:

 http://www.ngdc.noaa.gov/cgi-bin/seg/gmag/fldsnth1.pl

Declination values can change slightly over time as the earth's plates
shift, so if you have a declination value on an old USGS map, you may want
to check for your current varation.  You can plot a range of dates to see
the change over time. On the results page, the number you are looking for is
the first one on the first row under the "D" title.  This number is the
declination adjustment value, in degrees and minutes.  (Remember 5.5 degrees
would be the same as 5 degrees and 30 minutes.) Positive integers represent
Easterly adjustments and Negative integers represent Westerly adjustments.
There are links to notes on the results page that explain the details.

Also, this link for making your own transit looks like something a ham might
construct: http://www.rondexter.com/professional/sun/home-made_transit.htm


Thanks,
                Kevin.
------------------------------------------------------
Kevin Hemsley
kev@ida.net
KB7TYA


List Sponsored by AN Wireless:  AN Wireless handles Rohn tower systems,
Trylon Titan towers, coax, hardline and more. Also check out our self
supporting towers up to 100 feet for under $1500!!  http://www.anwireless.com

-----
FAQ on WWW:               http://www.contesting.com/FAQ/towertalk
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com