Originally Posted by d_wheel

Originally Posted by d_wheel
So far I have not had any success with aerial photography with my Spektrum radio. I have been doing some testing with an EasyStar with nothing but bad results. When I tried a 2.4 ghz down link (as mentioned in an earlier message), it decreased the range check by about 50%. Also, when the DX7 transmitter was near the video receiver, it completely blanked the signal. I decided not to try a flight test. Monday I tried it with a 900mhz video link (250 mw output power). The range check was decreased slightly (still more than the stated minimum) ,but the servos on the airplane would buzz when the video transmitter was turned on. I decided to go ahead and do a flight test which ended in very bad results. Everything was normal until the airplane was about 400' up and 200' out. At that point, the receiver went into failsafe. The motor shut off and the airplane started a slow right circle. There was a 7 mph wind blowing and each time it made a circle it was further and further away until none of us were able to see it. Not once during this time, about 3 or 4 minutes in failsafe, did it give any indication that it had regained link.

The video transmitters in both cases were about 2 inches from the AR7000 receiver. If I do any more testing, I will locate the transmitter further away from the r/c receiver, and also add a relay to the system to turn the video transmitter off if it looses link. This should be possible by connecting the throttle output to a “Y� cable and using it to control a relay controlling the video transmitter power. Another choice might be adding a mix from throttle to the gear channel to control the relay.

By the way the video systems worked with very few problems using a Futaba tx/rx. I have had it so high that it was just barely a dot in the sky, and at least ½ mile out. It would go into failsafe at times, but always came back almost instantly.

Later;

D.W.

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After finding the airplane (about 48 hours after it was lost) I have come to the conclusion that the fly away was definitely not related to the receiver losing binding with the transmitter as it worked perfectly the first time power was applied. I am about 80% sure that the problem was not related to the proximity of the video transmitter to the ar7000 receiver. When found, the plane was hanging from a tree limb about 15 feet from the ground. The canopy, which contained the video transmitter, was hanging by the associated wiring. After removal from the tree, I noticed that the wiring harness running from the main LiPo pack was actually melted into the plastic canopy latch, and looked as if it had been burned. When I pulled it loose, the wires started glowing and then burned in two (I had added an extension made from smaller gauge wiring which acted like a fuse in this case). My conclusion is that when I locked the canopy on just before launch the wires were caught in the latch. Several minutes later while in flight the insulation failed allowing the wires to come into contact. The high current burned the wire in two which in turn removed power from the motor and radio. When this happened, the radio appeared to go into failsafe, making me believe that the video transmitter had desensitized the radio receiver causing it to lose link. The short circuit could of course been caused by the crash, but I am sure enough of my conclusion that I will give it another try. I will, however, this time add the video transmitter cut off as mentioned in the earlier message just in case I am wrong. Walking around it the bush was fun when I was a youngster, but that era has long passed.

I will try to keep everyone updated when the test results are in.;

D.W.