Just getting into balloons, folks. In a few weeks time, I'll be attempting to radio-locate animals that have been fitted with VHF transmitting collars (150 MHz) from a tethered balloon.  I've proven the concept with the aerial VHF tracking equipment hanging below a copter. However, my piloting skills aren't quite up to piloting a copter so I going to start off with a tethered balloon.

My question is around orienting the payload (i.e. VHF receiver and associated tracking gear) under the balloon given that it will subject to wind influence. The rig will be slung under a picavet with a servo and bearing and am using an OSD to indicate which way the yagi is facing).  I'm expecting that the wind will rotate the rig and make the slow directional searching for VHF tones more complicated so thinking about methods to mitigate this. The simple answer might be to simply use a wind vane.

Alternatively, could I use my APM2/ublox and task it to fly north? The tracking rig would then be fitted under the 'APM layer'.  Perhaps use ArduPlane mode and just connect the rudder channel / servo to rotate the rig so it orients to north.

Any ideas as to whether this concept may work?



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  • Hey didn't see your reply Mark until now.  There are actually two transmitters on the animal collar.  The VHF component (150-153 MHz) is just a carrier tone pulsing at 30 ppm or 60 ppm depending on whether animal is alive or dead.

    Additionally there is a UHF (420 MHz I think) used for remotely downloading GPS data from the collar.  This requires a computer and a proprietary download box that calls every 30 sec and seeks to handshake with a collar prior to data transfer. I won't provide a link to the supplier as they cause me considerable frustration.


  • Michael - what information is contained within the tracking pulse? is it a simple RF carrier-wave pulse, or is there some useful positioning information in there?


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