[TowerTalk] fixating on true north

[Jim Lux]

At 09:08 AM 8/28/2006, Jim Jarvis wrote:

>Gee, guys, this is another of those 'once a year' threads.
>
>The average 3 element beam has a half-power beamwidth
>of +/- 35 degrees.  How closely do you really need to
>know where North is?  How much effort is it worth?

The nulls are somewhat sharper, and might actually be more important, but 
you're right for the main lobe.

>
>
>Use a compass, and look up the magnetic declination in an
>almanac, for pete's sake.  Or look on a marine or aeronautical chart.
>
>In critical applications, where you have long-boom VHF/UHF yagis,
>and are dynamically pointing at LEO satellites, I could see needing
>to know within a few degrees.

Or, pointing at a geo satellite with a small dish antenna, or EME, or a 
whole raft of things where sub degree pointing is important.

>  But even that should be satisfied by
>a declination adjustment to magnetic north.

Local magnetic oddities would probably dominate. To get sub degree 
positioning, you need something better.

Jim