[TowerTalk] Fwd: Finding North (was Strange behavior)

[Richard Solomon]

I would just get a couple or three
Boy Scouts over and average the
results.

73, Dick, W1KSZ

On Wed, Jan 25, 2017 at 12:37 PM, GARY HUBER <GLHuber at msn.com> wrote:

>
> -------- Forwarded Message --------
> Subject:        Fwd: Re: [TowerTalk] Finding North (was Strange behavior)
> Date:   Wed, 25 Jan 2017 12:35:36 -0600
> From:   Gary Huber <GLHuber at msn.com><mailto:GLHuber at msn.com>
> Organization:   AB9M
>
>
>
> As a former Field Artilleryman, I suggest you look at ;
>
> http://usacac.army.mil/sites/default/files/misc/doctrine/
> CDG/cdg_resources/manuals/fm/fm6_50.pdf
>
>  5-5 for POLARIS METHOD of determining TRUE NORTH see page 5-10.  (at this
> time the accuracy error is about 2 mils with a circle having 6400 mils)
> For the more accurate Polaris-Kochab method, see pages 5-3 thru 5-9.
>
> Even with a declinated magnetic instrument, the declination constant can
> vary dramatically in areas containing iron ore.
>
> For radio work this may be trying to use a precision instrument for rough
> trigonometry.
>
> 73 ES DX,
> Gary - AB9M
>
>
> -------- Forwarded Message --------
> Subject:        Re: [TowerTalk] Strange behavior
> Date:   Wed, 25 Jan 2017 05:39:21 -0800
> From:   jimlux <jimlux at earthlink.net><mailto:jimlux at earthlink.net>
> To:     towertalk at contesting.com<mailto:towertalk at contesting.com>
>
>
>
> On 1/25/17 4:12 AM, john at kk9a.com<mailto:john at kk9a.com> wrote:
> > Some day the magnetic pole will flip to the south pole.  This will really
> > change the declination numbers!
> >
> > John KK9A
> >
> >
>
> Go to
>
> https://maps.ngdc.noaa.gov/viewers/historical_declination/
>
> and select the arctic map, and click the checkbox for "modeled
> historical track of poles" or "observed pole locations"
>
>
> and you'll instantly see why people are talking about "the poles are
> going to flip relatively soon"...
>
>
> As a practical matter, in Southern California, where for years the
> declination sits around 14-15 degrees  (magnetic pole to the right of
> the geographic north), the change was about 0.1 degree/year.  So a 10
> year old topo map would be wrong by a degree.
>
> in 1900, the 15 degree line crossed just south of the Salton Sea (which
> didn't exist then...) and the 16 degree line went through the Channel
> Islands and Ventura county. In late 70s, the declination in Ventura
> County was about 14.7 degrees.  In 1990s it was around 14.1 degrees, in
> 2004 about 13.5, in 2013 about 12.8
>
> In the middle of the US, (along the agonic line, as it happens, but
> that's coincidence), the pole is essentially moving straight away, so
> the declination is changing slowly.  in Europe, though, the pole is
> moving cross ways relative to the line towards true north, so the
> declination is changing quite quickly.
>
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