Salut, merci pour ta réponse...

En fait je suis l'élève avec une Futaba 6exp 2.4Ghz,
mon avion a un récepteur 2.4Ghz
et l'instructeur à une Futaba "je n'sais pas quoi" qui n'est pas en 2.4Ghz.

Dans ce cas, est-ce la radio élève qui émet ?

Ok merci pour ta réponse !
Qu'appelles-tu 'limite' ?
Je joins le paragraphe du manuel (si ça peut t'aider à m'aider)...

Trainer switch (ACRO mode)
To utilize the trainer function, the appropriate trainer cord (available separately) and a second Futaba transmitter (usually
provided by your flight instructor or R/C club) will be required. When two radios are connected with the trainer cord, they are
both capable of operating the model, but it's usually best for the instructor to hold the radio that has been setup for the plane
to be flown (as it is already programmed to fly the model). When the instructor holds the trainer switch on his radio, the student
will have control. When the instructor wishes to regain control he simply releases the switch. Then he will have immediate, full
control.
If connecting the 6EX-2.4GHz to another 6EX-2.4GHz with the small, square “micro” trainer jack, use the “Micro to Micro”
(MM-TC) trainer cord (FUTM4415). Never connect the T6EX-2.4GHz trainer system with Futaba radios that have the
large round "DIN" connector type as it will cause your T6EX-2.4GHz to malfunction. The T6EX-2.4GHz transmitter may be
connected to another T6EX-2.4GHz, or any T4EX, T6EXA, T7C, T9C, T12Z, T14MZ, FX-40 series transmitter.

To use the trainer function:
1. It is best for the instructor to use the transmitter that is already set up for the model to be flown.
2. If the student's radio has PCM/PPM capability, set it to PPM.
3. If the student's radio has a plug-in RF module, remove the module.
4. Collapse the student's antenna when the student’s transmitter is conventional type.
(29-72MHz)
5. With the transmitters off, connect the trainer cord to both radios. (On the 6EX-2.4GHz the trainer jack is in the center of the
rear of the case.) Do not force the plug into the transmitter and note that the plug is “keyed” so it can go in only one way.
6. Turn on the instructor's transmitter. DO NOT turn on the student’s transmitter. It will automatically “power up,” but will not
transmit a signal. Set the servo reversing and trims of the student's radio to match that of the instructor's. If both the
instructor and the student use T6EX2.4G, the F/S function's set-up must be the same in both transmitters.
7. Turn on the receiver switch in the model. Depress the trainer switch on the instructor's radio. Use the student’s radio to
operate the controls (ailerons, elevator, rudder, etc.) and observe how they respond. Make any adjustments necessary to
the student's transmitter to get the controls to respond correctly.
8. Check to see that the trims are in “sync” by toggling the trainer switch back and forth a few times. The controls on the
model should remain stationary. If the controls do not remain stationary, this indicates that the trim settings on the
student's radio do not match those on the instructor's radio. Adjust the student's trims as necessary.
Note: When the instructor initially depresses the trainer switch on his transmitter, there will be approximately one-second delay
before the student takes control. In most situations this momentary delay will go unnoticed. The trainer switch does not work in
heli mode.

Et bien ok, je note !
Un grand merci à tous d'avoir fait avancer le shmilblik !
Le sujet est clos, je le renomme 'résolu'
Encore merci