There are 3 options that I know of :

1. Send it to Spektrum and have it repaired. Their Tech's are Good folks. Fairly rapid turn around and typically little, if any, charge.

2. The exact replacement antenna is available from a place called "Din ball" (I believe they are out of Hong Kong). I have dealt with them with good results before, however, it takes a while for shipping.

3. Carolinas R/C! - They call this an antenna for "air models", but 2.4GHz is 2.4GHz. There are 2 differences between the original and this replacement. First, the antenna is foldable, meaning that it pivots at 90 degrees. And second, the Coax lead that connects to the circuit board in your Spektrum TX is about 4" longer.

I recently replaced the broken antenna on my Spektrum module-Airtronics M11 with the antenna from Carolinas R/C! ...though the Coax lead is longer. What we are dealing with is a small routing problem... It's NOT a 27 or 75MHz antenna that is tuned to the wire length, and does not pose a signal attenuation concern.

Jim