[aprssig] NMEA output GPS or compass?

david vanhorn kc6ete at gmail.com
Fri Jun 29 13:27:49 EDT 2018

Thanks all.

I am going to hold off till I find a fluxgate compass.  The GPS route would
"work" but this thing has enough issues already.

The Boltek LD-250 is " Long Range detection Designed for mobile use in a
moving vehicle with a GPS or Compass connected " (From their web site)

Their software doesn't work with any known map program.
The unit sends strike information as bearing and distance relative to the
front side of the sensor.
If you add a compass, the strikes are rotated accordingly.
The strikes are not converted to anything like an object at a coordinate
though, so if the vehicle is moving, they are "smeared" across the map.

It's only really useful while moving if the strikes are converted to
absolute rather than relative coordinates, and then the image is rotated
and panned accordingly to the vehicle rotation and motion.
I could easily live without an actual map

The GPS wouldn't give me workable heading data when not moving, and the
LD-250 doesn't give useful data while I am moving..

With a compass, at least I could park in whatever direction works, and I'd
get a display rotated so that it's oriented north up.

It's a fixed location instrument in a mobile package.   The only plus is
that it doesn't require a full PC with PCI slot to run.

Basically, in the 10 years since I last used it, the half-assed
implementation of their software hasn't improved at all.   I need it to be
at least 3/4 assed. :)

It would be really cool if some working mobile app/program whatever could
be trained to hear their data and plot it on a working map.


<ddd> - corrected strike distance 0-300 miles
  <uuu> - uncorrected strike distance 0-300 miles
<bbb.b> - bearing to strike 000.0-359.9 degrees
       <cs> - checksum in hex
   <cr> - carriage return
   <lf> - line feed


On Thu, Jun 28, 2018 at 7:25 AM, david vanhorn <kc6ete at gmail.com> wrote:

> I'm reactivating an old project, and I would like to find an NMEA output
> GPS unit like the old Garmins with their four pin connector, or a compass
> with similar output.
> What I've seen in compasses are crazy expensive ($500), and GPS units seem
> to all be USB output now if they have any external data connection at all.
> What I absolutely need at a minimum is a compass or GPS with an NMEA
> output. The system has NMEA+ NMEA-, +12V power to compass/GPS and ground.
> If it's a GPS unit, I would prefer some sort of simple "puck" style unit
> rather than something with a display and buttons to misconfigure.
> Any sources coming to mind?
> --
> K1FZY (WA4TPW) SK  9/29/37-4/13/15

K1FZY (WA4TPW) SK  9/29/37-4/13/15
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