Campgems

I got a shock this morning. I've got a Phoenix Fun star that I couldn't see, so I recovered in into some contrasting colors. Old eyes.

Anyway, this morning was going to be the first flight with new clothes. I had the receiver and servos out during the recovering and I did a quick range check. It failed miserably. I'm flying 72mhz. I found that if I pointed the stub of the antenna at the plane, it went bezerk at 25 ft. I've never had one of my planes even twitter a bit at 300 ft, so this was a shock. If I turned the TX so the antenna, as short as it was, was parallel to the plane I could get some more distance, I didn't test how far. The last time I flew the TX was a couple weeks back and my receiver battery opened up. Three of us had turns wiggeling the stick why the plane wenr around lazy circles for several minutes. Did one of the other set of hands screw up my TX. I went back to the car and got my backup TX (both Futaba 9C's. Same failure.

I had the antenna wire in a tube, with about an inch folded back on the end away from the RX. I just pushed it back into the fuselage for almost the full length. I had about 8" of excess wire that I routen in a big U and taped it to the fuslelage top. Well, when I pulled out the receiver and antenna wire and pulled the wire out straight, I could easlly get 100 ft with out failure. I have been flying not only this plane, but several others with the same setup after hearing that it was how one of the moderators flew for the reviewes he did.

I didn't try to fly today, I brought it home and checked things out again. In my back yard, about 25ft was the maximum. I pulled the Xtal from the receiver and found it was a GWS xtal. I replaced it with a futaba Xtal. No change. Just to make sure, I replaced the receiver with a new one. THe old was a Futaba R168df and the new is a R148df I didn't try looping the antenna again, but punched a hole nest to the rudder and fished it out the back of the plane.

I'm guessing, and that is all it is, that perhaps one of the ceramic filters has gone south in the 168 receiver. It wasn't very old, but it may have crashed once. Any other ideas about what may have been going on. By the way, this was with out the engine running, so it is not a viberation issue.

Don

majortom-RCU

My Feedback: (40)

Don, I've had a similar experience. I've set up maybe a couple dozen models with the antenna running forwards then backwards (or backwards then forwards) in the fuselage interior, making the U-turn as wide as space would permit, and never had a hint of a problem with it. One plane the instruction manual advised that method. My most recent installation was in a GP Reactor, and I had the same miserable results you describe with range check on the ground. With this Reactor, the antenna tube comes pre-installed in the ARF, and that's where I ran the antenna. Being obstinate, I put it in the air a couple times and got intermittent glitches, nothing plane-destroying, but easily might have been if I hadn't been alert for it. Switched to an exterior straight-line antenna set-up and problem went away. A set-up that 'always worked' all of a sudden doesn't work. The Reactor is a balsa frame with film covering, no CF, no metal parts. I will say it does have three tail-mounted servos with long extensions, so that would be my only guess: antenna too close to too much servo wiring.

Campgems

That servo setup is similuar to mine, only I only have two. I'm kind of wondering now if my white knuckle four flights with the plane had more to do with glitches rather than the lack of visibility. Hopefully, I have cured both now.

I've got two receivers that I'm going to send in for a checkout. One was crashed and a couple of the servo lead housings broke at the receiver case. The other is the one I just pulled out of this plane. I'll probably save enough on shipping that it will be worth while.

Don