This is the ultimate upgrade for your FrSky or Spektrum radio. For Spektrum, you will need a u.fl to RPSMA pigtail (found on EBay for $3). For FrSky, this attaches to the RPSMA port directly.
Where to buy:
Readymade RC: https://www.readymaderc.com/products/details/vas-shapshifter-selectable-gain-2.4ghz-antenna
Stone Blue: https://stoneblueairlines.com/vas-2-4ghz-shapeshifter-antenna.html
