I'm new to this forum, so I hope I post this in a useful place..... I just got a CM15A and was also VERY disappointed in the wireless range of the device the I started looking at various mods on this forum and had an idea to take the antenna off my old TM751 module and adapt it to the CM15A. The antenna on the TM751 is a simple telescoping antenna an i reasoned that it's supposed to receive the same frequencies so it's extended length must be correct.
When I disassembled the TM, i got a suprise; the antenna has no physical connection to the electronics, it's coupled inductively with a solid piece of plastic between the wire from the module and the antenna. This gave me the idea of removing the TM751 antenna and simply attaching it to the outside of the CM15S antenna, I chose to wire tie it there but i think three are many ways to accomplish this, but i wanted something that wouldn't affect my warranty.
The results were ASTOUNDING.... using the mini keychain remote before the mod, i could only go through the outside wall and about 10 ft on the other side and no at all from inside the car. With my simple mod, I was able to increase the range to about 200 ft outside and about 60 ft from in the car. I suppose that any metal piece with the same length (12 inches) would work as well.
I simply can't understand why X10 has chosen to neuter this device the way they have. The TM751 is PROOF that they USED to know how to do this!