I thought I said that...
--
Thanks and 73's,
For equipment, and software setups and reviews see:
www.nk7z.net
For MixW support see;
http://groups.yahoo.com/neo/groups/mixw/info
For Dopplergram information see:
http://groups.yahoo.com/neo/groups/dopplergram/info
For MM-SSTV see:
http://groups.yahoo.com/neo/groups/MM-SSTV/info
On Tue, 2015-12-01 at 10:32 -0500, Michael Clarson wrote:
> Another caution: Magnetic "North" can vary substantially from the
> predicted declination. I always calibrate my compass by sighting a
> physical object and comparing the bearing to a map. I learned this
> while trying to aim a microwave antenna on top of a ridge between
> Bethlehem and Harrisburg PA. Mountain loaded with iron ore. My compass
> was about 30 degrees off! This mountain is one of the few places on
> Earth where one's compass can be off that much due to local
> conditions. --Mike, WV2ZOW
>
> On Tue, Dec 1, 2015 at 9:01 AM, David Cole <dave@nk7z.net> wrote:
> If you are doing this by hand, as I do, then remember, to keep
> the map
> and your bearings, in either True, or Magnetic North, I always
> keep my
> maps in True North, and adjust my compass readings to True
> North, prior
> to plotting them.
>
> If you take a Google map, it will be True North, while your
> uncompensated compass, will be in Magnetic North. I use
> Google Earth
> images to draw my plots on.
>
> You need to convert both your map, and your readings to the
> same units,
> either True or Magnetic North, before you draw a bearing line
> on your
> True North oriented Google map. Here is how I get them to
> match the the
> easy no math way.
>
> I go here: http://www.acscdg.com/ and get a map of a long,
> straight,
> road that runs dead N, S, E, or W in my area, the actual
> bearing does
> not matter, it only matters that you know the bearing of the
> road
> exactly, and can read your compass to that same accuracy,
> hence why I
> use N, S, E, or W, they are easy to find on a compass, and
> almost every
> city has N/S/E/W roads.
>
> I pick a road that is long, and has a sidewalk, that way I can
> stand on
> the sidewalk, and sight down the sidewalk, not looking off to
> the side
> and sighting down the road from the sidewalk, thus introducing
> parallax
> issues. I then take my compass to that road, and sight down
> the
> sidewalk.
>
> I purchased an adjustable compass so I just adjust the compass
> to read
> the heading of the road, and my compass is now calibrated to
> True
> North.
>
> See: http://www.ngdc.noaa.gov/geomag/declination.shtml for why
> you need
> to do this...
>
> I then go home and take a bearing on something far away, from
> a known
> spot on my property, and write that bearing down. Then the
> next time I
> go out and start looking for RFI, I just sight on the object
> again, from
> the same spot, and adjust the compass if it has moved... I'm
> now all
> set to do True North bearing drawings...
>
>
> --
> Thanks and 73's,
> For equipment, and software setups and reviews see:
> www.nk7z.net
>
> For MixW support see;
> http://groups.yahoo.com/neo/groups/mixw/info
> For Dopplergram information see:
> http://groups.yahoo.com/neo/groups/dopplergram/info
> For MM-SSTV see:
> http://groups.yahoo.com/neo/groups/MM-SSTV/info
>
>
> On Tue, 2015-12-01 at 02:18 -0500, Roger (K8RI) wrote:
> > Select your area with as much resolution as possible.
> > Drive to a location, take a bearing. using the Google
> distance ruler,
> > draw a line through your point. Drive to another point and
> repeat. Two
> > bearings are often sufficient, but three leave a small
> diamond for the
> > region of error. Much easier to do than explain, although
> there is a
> > learning curve.
> >
> > It gets messy with RFI hunting when there are multiple
> sources, with
> > overlapping and similar patterns as in multiple networks or
> an area
> > where there are a mix og cable and outside antenna and the
> users just
> > wired the preamps and cable together. This sometimes can
> lead to a much
> > larger region of error.
> >
> > 73 es good luck
> >
> > Roger (K8RI)
> >
> >
> > On 11/30/2015 8:16 PM, Karin Johnson wrote:
> > > I'm planning on doing some RFI hunting and wanted to know
> if anyone
> > > knows how to plot compass vectors on Google Maps?
> > > I need to plot intersecting vectors from a direction
> finding loop to
> > > find the source of an RFI generator.
> > >
> > > Karin K3UU
> > > Palm Harbor, FL
> > >
> > > _______________________________________________
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> > >
> >
> >
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