I understand this is an old request. However, the problem continues to plague those of us that use these type modules.

So here's my remedy/solution to the problem:

I recently had a similar issue happen to my SM1001 TX Module. The pivot point on the antenna cracked and needed attention. I searched for the replacement antenna and actually found the correct Spektrum p/n:SPM75001. However, no LHS shops had it in stock. Bummer.

I then took the approach to modify my SM1001 TX Module to accept a standard 2.4Ghz RP-SMA Screw on type antenna. Minor milling of the Spektrum case was required, but worth it to prevent this from holding up the show down the road. Plus, it allows me to test/use various gain antennas moving forward.

Required:

Dremmel/Rotary Tool
4" RP-SMA -to-> IPEX (similar to: http://www.adafruit.com/products/852)
2ea. Flat Washers

Once the case is opened, you will find the iPEX end of the coax antenna wire is pretty easy to remove by lifting upward on it to release it from being snapped into position. Then remove the swivel portion of the damaged antenna post. Mill away the tube portion where the original antenna was mounted on both the top and Inside areas do the top cover. Place one washer over the threaded RP-SMA termination. Slip the threaded portion of the Reverse-Polarity SMA (RPSMA) connection from the inside of the top cover. Install the 2nd flat washer over the threads of connector, then install the supplied nut. You may want to add loc-tite or RTV to the shaft of the threaded connector before the nut is secured. Gently tighten the nut while using a second wrench on the bottom side. Carefully install the smaller right angle IPEX end of the coax cable by pressing it onto the PCB and carefully reassemble the case while watching the routing of the cable around the stacked/layered PCBs - don't forget the plastic riser for the bind button.

Completed setup with spare 2.4ghz 5dBi Gain antenna installed (as a test)...

So far so good. I tested range and I have no complaints with either a 3dbi or 5dBi Gain antenna installed. No glitches and as far as I could see, I had control without boundaries/limitations.

I hope this helps.