David's method of using a topo map and sighting an object is the best way.
A GPS requires it to move in order to get a bearing, and magnetic compasses
have issues. Besides the difference between magnetic and true north, they
are often affected by local conditions. I have encountered errors up to 40
degrees in the mountains between Bethlehem and Harrisburg PA, probably due
to all the iron ore in the ground. --Mike, WV2ZOW
On Mon, Jan 23, 2017 at 7:23 AM, David Robbins <k1ttt@verizon.net> wrote:
> Compasses in smartphones are like the ones in your car, a magnetic sensor.
> So they are affected the same way as any other magnetic compass.
>
> A gps can only tell you what direction you are moving and can take quite a
> while to give a good bearing especially in cluttered environments around
> buildings or even heavily wooded areas. The best way to get a bearing with
> a gps is to mark a waypoint at the tower, preferably by averaging the
> location for a minute or two if your gps supports that, then going at least
> 100 yards away in the general direction you want to check... when you get a
> good distance away check the bearing back to the original waypoint which is
> of course the reciprocal of where the antenna is pointing.
>
> My preferred method is to find an obvious feature on a map that you can see
> from the tower and get the bearing to it from a good map then use that to
> line up rotors.
>
> David Robbins K1TTT
> e-mail: mailto:k1ttt@arrl.net
> web: http://wiki.k1ttt.net
> AR-Cluster node: 145.69MHz or telnet://k1ttt.net:7373
>
>
>
> -----Original Message-----
> From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of
> Roger
> (K8RI) on TT
> Sent: Monday, January 23, 2017 03:16
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Strange behavior
>
> If I'm not mistaken the smart phones derive the compass from GPS which is
> true, not magnetic so it wouldn't require a correction.
>
> 73, Roger (K8RI)
>
> On 1/22/2017 8:43 PM, Jim Brown wrote:
> > Thanks Dick. It's also important to realize that accuracy will depend
> > on the sensors in the phone it's running on, as well as surrounding
> > stuff as others have noted.
> >
> > I bought an unlocked Motorola Moto X Pure phone last fall that I like
> > it lot. I have two compass programs on it that SEEM to work well. GPS
> > Status and Compass 360. Both automatically correct for declination. I
> > haven't done a serious test of either of them. The one you recommend
> > also looks good.
> >
> > 73, Jim K9YC
> >
> > On Sun,1/22/2017 5:21 PM, Richard Solomon wrote:
> >> OK, I'll be a bit more specific.
> >> There's an App called GPS Essentials.
> >> No Owls, no bugs, has a very accurate compass.
> >
> > _______________________________________________
> >
> >
> >
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> > TowerTalk@contesting.com
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>
>
> --
>
> 73
>
> Roger (K8RI)
>
>
> ---
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>
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