I upgraded the original antenna in my Turnigy 9x transmitter. I raplaced it with a 2.4 Ghz Biquad Antenna.
Antenna’s semi rigid coax cable is soldered directly to the radio’s module which introduces less losses in the connector. The cable is fitted through the drilled hole and additionally secured with a pertinax plate glued to the enclousure.
To construct the antenna itself you can find the instructions here.
Because the semi rigid coax cable is quite fragile I designed a mount that connects the transmitter and the antenna.
The antenna itself also neded to be protected so I designed an antenna cover aswell.
3D printed parts are avalible here.