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Cheap Azimuth Indicator ??

I was in the Army Signal Corp in North Africa and Italy during WW2 and we used a passenger car with a steerable loop antenna mounted on the roof to locate suspicious radio signals. When we took a bearing we manually turned the loop approximately to the expected signal direction.

With a standard siting compass, standing away from the car we measured the azimuth to which the loop was pointing. This "calibrated" the azimuth indicator in the car which showed loop's rotational position.

If there is no azimuth indicator in the vehicle, a simple synchro repeater could be attached to the pan axis.

I would expect the yagi antenna would be sufficient as an alignment element to sight from the compass. Probably good to +-5 degrees.

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Virg Wall
Reply to
VWWall
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It probably won't work using two stand-alone GPS receivers, but there are GPS-based compasses. I've seen one - from Furuno, I think - that had two or three antennas in a single housing about 3 ft diameter.

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Peter Bennett, VE7CEI  
peterbb (at) telus.net
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
Reply to
Peter Bennett

So does my Jeep. Not sure about its being fluxgate, though, there are some magnetoresistive devices (Honeywell, I think), that respond to geomagnetic field levels.

What resolution does the Q45 compass have? The Jeep only does half-quadrant.

--
"For a successful technology, reality must take precedence 
over public relations, for nature cannot be fooled."
                                       (Richard Feynman)
Reply to
Fred Abse

Yep. I designed such a chip for Honeywell Sensor Division (Minneapolis) in 2007-2008... took 18 months... lots of bells and whistles.

In the mirror text, half-quadrant, on the map screen fairly smooth, so I haven't taken note of the granularity. ...Jim Thompson

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| James E.Thompson, CTO                            |    mens     |
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Reply to
Jim Thompson

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Issues with local magnetic field distortion can be handled if you can raise the camera into position and then rotate it several times continuously. A microprocessor (not included) can sore a map of the local field anomalies and find magnetic north (my watch's compass works the same way).

A uP in the camera head can handle all of this (Parallax sells these as well) plus encode the resulting data into the NTSC blanking lines. Or you could use a coupe of low power RF modules to send the data down sans wires.

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Paul Hovnanian     mailto:Paul@Hovnanian.com
------------------------------------------------------------------
Quantum Mechanics: The dreams stuff is made of.
Reply to
Paul Hovnanian P.E.

John Fields Inscribed thus:

Doesn't Garmin make a hand held compass !

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Best Regards:
                          Baron.
Reply to
Baron

Those probably only work in a rural area with a clear view to the sky. As soon as you get close to buildings or an airforce base (radar) GPS is very inaccurate.

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Failure does not prove something is impossible, failure simply
indicates you are not using the right tools...
nico@nctdevpuntnl (punt=.)
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Reply to
Nico Coesel

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