How I almost lost my Quadcopter

hubsan-X4-unboxingAfter having flown a little Hubsan quadcopter around for nearly a month, and all but destroying the first one, my second Hubsan X4 Quad lost control over some trees.  Depending on where it fell, the area was possibly heavily wooded and on someone else’s property.  Fortunately, after driving around the neighborhood, my wife was able to pick out the quadcopter’s bright blue lights shining in a small drainage ditch.

So what went wrong?

The controller I normally use was acting strange when turning (which I haven’t resolved yet), so I picked up the controller previously used on the smashed quad.  Everything was working well until I dipped fairly low 50 feet away or so and lost communication.

Looking at the controller battery indicator, everything seemed to be as it should.  Given the loss of control and the fact that I was using the older controller, I decided to check the batteries with a voltmeter…



Your contact info – a great way to get things returned!

If possible, print* your phone number on this little quad.  If you loose it, there’s a good chance of return, especially since your neighbor or whoever happens upon it will probably want to know what it is.

The other thing I did was change the batteries in the transmitter.  Although the display on the controller showed no problems, after testing one with a voltmeter, it displayed at 1.239 volts.  The same type of battery read at 1.6 volts out of the box, so I went ahead and changed them out.

More Transmission Problems

After this ordeal, my quadcopter started losing communication in nearly the same place in my yard.  After posing the question of what this might be on Reddit, someone suggested that it was a factor of RF reflection.  My truck was somewhat in the same direction as the quadcopter where I was flying it from, although not directly line of sight.  I know very little about radio frequency science, but maybe this was a factor.

Whether or not it was actually RF reflection causing this disconnect, I moved the transmitter as suggested, and the problem went away.  I still see a glitch from time to time, but no “dead birds” in the exact same spot anymore.

*I marked my propellers with a Staedtler permanent marker.  These “F” models are available in a four-color package from Amazon.  Although they’re not cheap, from my experience the ink seems to NEVER come off.  Alcohol supposedly can be used for removal, but after marking up a beautifully anodized machine at my job as an engineer, it seemed to be unnaturally resiliant to my best efforts of removal.  This subjected me to a fair amount of harassment from my coworkers, but on the bright side, the machine did work…

I’m fairly certain the marks still exist there 3+ years later.

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