Ramblin,

May as well add my $.02 so keep in mind I'm just specultain' but,

As I'm sure you've already found out or heard, one of the problems with high frequencies is multipath. The frequency waves are very small(short) and fast and do not penetrate well. What can happen is the signals end up bouncing back and forth off of surrounding metal objects. One of the fears early on when 2.4g was first introduced was degraded signal from multipath so I'm sure thats why all the different multiple antennas/receivers schemes we see on the various radios out there.

What I see in your pic is one antenna not only doubled back along itself but also in between the receiver(full of metal objects and an rf producing microprocessor...though not much) and a big honking metal tube. I would have turned the receiver around 180deg and routed the antennas out and away from the tube. The other antenna is mostly away from everything so you would think the Rx should have had at least one good signal source but...... who knows.

Also, and I'm sure I'm gonna catch some flame scorching for this but I don't see any foam on top of the receiver. The zip tye is not a bad way to mount the rx and I have done it myself. However, you could still transmit some vibration as its directly contacting the airframe. I would have used foam all the way around the receiver.

Which brings up a good point. How is your battery mounted???? Batteries can be subject to vibration problems as well. It might have read fine on the ground but once the engine was started you MIGHT have had a problem. Also keep in mind that it's a known fact that once the engine is running the battery will see increased voltage draw. The vibration getting into the servos causes them to use more holding voltage. Vern Hyde, Chip Hyde's dad proved this back in the pattern days and is a major reason why engine soft mounts were developed. It allowed them to use smaller batteries (because of the lower amperage draw while the engine was running, so lower aircraft weight) and increase both airframe and electrical reliability. the reason I say this is because 4.5v is getting a little low with the engine off. With it on, I can reasonably see an even greater voltage drop.

Mike