Build your own 900MhZ antenna.

thingiverse

Why spend money on "immortal T" 900MhZ antenna and wait for it to arrive from China for a month "on a slow boat" when you can build your own? After all, famous "Imortal-T" by TBS is not that immortal. Mine broke down before my first flight. I had massive fail safes at 50 feet. Imortal-T if you grab it by the top and try to spin it, you will break it immediately. (weak design) The joint of the two radiating elements should be covered with epoxy before encasing it in antenna housing, which they failed to do. All you need is one of the rubber ducky antennas or FPV video antenna which you no longer need and two pieces 83.3mm of copper wire to make a dipole. Solder one part of radiating element to the positive (center wire of the coax and another to ground of coax) Also, use some antenna tubing to protect the wire from bending. With RF Vector Analyzer N1201SA I was able to tune it exactly to 900MhZ with SWR 1.2. by clipping the ends of it. Then I designed this housing to make it trully indestructible. SWR and tuned frequency will change with housing, tubes and rubber end-caps, so adjustment is needed by clipping the ends after final assembly. Very small increments need to be clipped as you can go from lower to higher frequency but not the other way around. If you past the desired frequency, than antenna is no good. STL file.. print two of them with opening facing down. no supports needed. Good luck!