All,
Well, I have setup as close as I can, the scenario David has indicated might have caused his crash. Using two JR 10 channel transmitters, one older straight 10 channel, and the newer 10X. Those are the only JR 10 channel transmitters I have access to at this time.

In my setup the newer 10X transmitter & S-mode 950 receiver are matched to the airplane. In this case a Dave Patrick Ultimate biplane. Four servos one for each aileron, two servos for the elevators / elevator drives Aux 3, one rudder, one throttle... An older relatively simple setup! I use two channels for aileron control, aileron and flap with a simple mix. Each servo top & bottom left wing is connected to a Y-harness, which then is plugged into the receiver aileron channel. Each right wing servo top & bottom is connected to a Y-harness and the receiver flap channel.

In my basement I setup essentially the old swamp test with each transmitter on the same channel. The older 10 channel being the interfering transmitter. With the interfering transmitters antenna collapsed and the newer 10X transmitter antenna fully extended both transmitters ON... the interfering transmitter will not cause a lockout condition until it is closer to the receiver antenna by more than half the distance of the operative transmitter. With both antennas’ extended lockout occurs with almost any relative positions of either transmitter.

I can NOT EXACTLY duplicate David’s findings of elevator movement with this setup. The operative / controlling R/F link always goes to HOLD or pre-set fail-safes if selected, when the interfering transmitter gets relatively close enough to activate the fail-safe.

Anyway what I did find and can duplicate time and time again.. Is that when both transmitter antennas are extended, I can continually create a strange situation by positioning the interfering transmitters antenna slightly closer to the airplane.

One of servos...the flap / left wing servo...one only... drives completely full travel to the down position. Yep, one servo only out of 8 servos in the airplane! It looks to me like that servo is actually getting an R/F signal directly not through the receiver (later I find this might not be the case! The strange movement / signal is getting to the servo through the receiver I believe.) Remember the interfering transmitter in this scenario is closer than the operative transmitter to cause this servo action. The servo will drive full throw that same direction only when two JR transmitters are ON. One transmitter alone will not cause a full throw movement of the servo! If I put the operative transmitters antenna within inches of this servo it will jitter a little but will not travel full throw?? Fact is other servos will jitter very slightly with close transmitter antenna proximity… something I consider almost normal and no flight risk.

Now for the really interesting finding…. Same scenario as described above.. But now the interfering transmitter is my Futaba 14MZ. What do you think happens to the servos now? Well, the same flap servo now moves full travel UP not down! And now my elevator servos in some cases will both drive full down also, and in other relative transmitter positions will split.. Yep one UP one DOWN... and the aileron / flap UP.

Keep in mind this test and these observations were made within my concrete rebar enforced basement walls. For me to cause the operative system to do anything but lockup / HOLD the interfering transmitter had to be closer than the operative transmitter. But the reactions of the 10X / S-mode JR receiver # 950 to JR interference was different than Futaba interference. My Futaba transmitter seemed to cause more strange servo reactions from a relatively father distance away than the JR 10 channel transmitter??

Who knows? what a turn on shoot down situation might cause in an open field? In my basement I could not cause the strange servo action unless the interfering transmitter was in a closer proximity than the operative / controlling transmitter. Until I witnessed this strange servo reaction for the first time today…. I would have said this would have been impossible at a flying field or in my basement…. But now I’m not so sure about the open field situation.

I can tell you I am ready to jump head long into the 2.4 world…if for no other reason than eliminating possibility of this type of shoot down. Shoot downs have always been my greatest fear when flying R/C aircraft. With a little luck maybe those shoot down days will be behind us forever once SS gets fully debugged and up to speed.
Lee H. DeMary
AMA 36099