Spektrum SPMMSJR9 - Manual (Page 10)

Spektrum Air Module 10
4. Connect the antenna’s fitting to the module, screwing it securely in place.
Important: Never operate the module without the antenna
connected. Doing so could overload the internal electronics and
could cause a failure.
5. Turn on your transmitter. The LED on the back of the module should come
on after a few seconds. If not check to be sure the transmitter is in PPM
modulation mode (Step 3 in preparing the transmitter above).
Installation