GoNavy

My Feedback: (15)

Here's a report and my present thinking:

Upon further investigation, both servos on the rudder channel glitched; tho the jitters in the servo in the nose could not be heard, they could be felt by placing a finger on the arm. I eliminated the power board, but that did not change anything. I connected the two elevator servos to the receiver, and they glitched big time.

Ralph at RAM opined that the receiver "needed to be tuned" because it was "reading voltage variation" in the beacon circuit. He said that in the many years they produced the beacon this problem was reported only once before.
I substituted two other receivers with no change in the glitching. Leaving the antenna "coiled" at the receiver instead of laid out its length made no difference.

I tried relocating electronic items that could be relocated, 21 variations in total. In most cases this made no difference, but there were a few notable exceptions. 1 Moving the antenna from the rear fuselage and running it forward resulting in greater glitching. 2. Running the antenna at a right angle to the fuselage seemed to virtually eliminate the problem. 3. Disconnecting the battery from the nose, and connecting it to the gadget at mid fuselage resulted in increased glitching.

Perhaps the strangest was this: Adding two 12 inch extensions, one from the battery to the gadget, and one from the gadget to the existing leads to the beacon in the tail, eliminated the glitching. With this extra wiring I could put components back into the fuselage and there was no glitching unless I put my hand close to the gadget, within a half inch or less, whereupon slight glitching would start. Remove my hand and the glitching stopped.

I called Airtronics and learned they no longer service their 72 MHZ equipment. They referred me to the fine folks at Radio South in Georgia who gave me of their time and advice. They opined that the receivers did not need to be tuned. They felt that the EMI radiating from the beacon wiring had a harmonic that was being read by the receiver; that I might try, as an experiment, a Hitec receiver that synthesized frequencies, and alternately said that swaping the 72 MHZ system for 2.4 GHZ would solve the problem. They felt the twisted wire pairs I had used for the beacon system wires were insufficient to reduce the EMI and suggested shielded cabling would probably do the trick.

If I eliminate the dimming feature, run a flat 9 volts to the beacon, there is no glitching. That is what I probably will do; Replacing the twisted two wires with shielded wire, or adding shielding around the twisted pair, at this late stage, would be difficult, probably not possible in places (i.e., the 18 inch long vertical run in the leading edge of the fin).