Geistware

My Feedback: (16)

I just installed a R138DP PCM receiver in my PW Extra. This is my problem. With the engine off, I get 65 paces (180ft) of range along the latitudinal axis of the plane but only 35 paces along the longitudinal axis. With the engine on, I get 60 paces and 30 paces respectively. I have never experienced this before in any other plane.

I normally get 40-50 paces with my other planes and a R148DF PPM receiver. I want to know should I be concerned with the difference?

My transmitter is a Futaba 9C

Lynx

It's a little unusual to have quiet that much difference, there's probably something in the plane helping to block the RF. Any long bit of wire will help block the signal, try playing around with wireing configuration if you can to see what helps.

LarryC

Another thing to consider. Is the antenna wire running in a fairly straight line down the length of the fuselage?
A quarter wave antenna, such as we have on our receiver, will exhibit somewhat of a null straight off the end of the wire. Usually there is enough pattern distortion of the antenna from other wiring and turns in the internal portion of the the antenna on the planes to make this not show up. It could be that that is all it is.
As Lynx suggests, a simple change in the wiring might change the situation.
30 paces is probably enough, but it's kinda scary thinking that your radio is at its worst when it's going straight away from you!
I might add that the only time I've had a range check problem was with a plane with servo extensions running down the length of the fuse. The antenna was in a tube in the corner
of the fuse. I had to reroute the antenna out the top and to the fin to cure it.

Good luck. I'm sure you will sort it out.

Larry

Geistware

My Feedback: (16)

What I have come to discover is that my wing tub (aluminum) may be effecting the signal! What I don't understand is why would the signal be weak there if the antennae is running down the length of the fuselage and my weakest signal is broadside to the fuselage.

Lynx

Any piece of metal reflects, and refracts RF radiation. Depends entirely on the shape, but depending on orientation and geometry, it can actually absorb and retransmit the RF energy at a slightly different frequency. Just adds to interference. You add all these things together along with your wiring and any other inherent problems and you'll get range problems eventually. Less metal, less complex wiring setups are the only solution. Do whatever you can to reduce the complexity.