Is it possible to run dual antenna's off of the 2.4 controller such as running the stock Rubber Ducky and a half sphere helix? What would be the loss of power?
It won't work very well.. and may even damage the controller due to the impedance mismatch.
The antennas would be out of phase and interfere with each other at the receiver causing drop outs and other weird issues.
Dual antennas are really for the receive side.. with diversity switching.
Same goes for your home router.. only one antenna usually transmits (per radio transmitter). and the receive side is via diversity.