Saturday, April 26, 2014

1.4 km away, FPV Touch-and-Go behind Hill in Rain...


Flew in the rain 1.4 km away over a hill and did an FPV touch-and-go... followed by a 2-km SplineNav scenic flight back, and near electrocution of the copter (oops!)—and all of that in one single epic flight!

It's very hard to get good FPV range flying near the city: even with 1.3GHz and a high-gain (directional) antenna on the receiver, we only get about 1 km range hugging the terrain (much longer range is available flying high, but that doesn't make for as interesting videos).

So we headed out to the countryside to find radio quiet, and left the bulky high-gain antenna at home. With just a Circular Wireless SPW12 on both tx and rx, we were able to fly 1.4 km away, duck behind a hill, make a touch-and-go, and still get perfect video back the whole time.

Unfortunately the video still doesn't work well flying behind broad-leaf trees, even at much shorter ranges. Evergreen needle trees don't seem to be a problem though, perhaps due to their lower moisture content. We're now using a Lawmate 1000mA 1.3 GHz transmitter, which seems to work a lot better than the ReadyMadeRC tx, and is much lighter. We use RangeLink UHF for radio control, which seems to be pretty much invincible at any distance.

After doing the the touch-and-go on the grassy hill 1.4 km away, we engaged SplineNav and did a 2-km scenic flight back on autopilot. The rain was really picking up, and moisture got into the gimbal electronics, which made the GoPro twitch wildly from time to time, but otherwise the water didn't cause any harm.

Note the temple with the four characters 周氏宗祠 we fly over at 5:18. That's where my wife attended elementary school, long since abandoned and with trees growing up inside it.

The change in weather on the flight back seems to have affected the barometer, because where SplineNav was supposed to have gone under that last power line, it went straight through inside. Really amazing that it made it through that narrow gap with no damage other than a split prop tip. These high-voltage wires are bare of insulation and carrying the power for the whole village. Fortunately the electricity didn't arc across right through the aluminum arms of the copter!

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