Dipole Antenna for R9M etc 900MHz FrSky R9

thingiverse

Antenna T piece for Dipole Antenna. My antenna was designed specifically for an R9M, as the stock FrSky antenna falls far short of the excellent performance offered by the TBS dipole. My antenna is based on https://youtu.be/cJIFynAfG2I, with active and GND elements positioned at 77mm for 868MHz. I used RG402 coax to ensure my 1/2 wave length in the coax, including its velocity factor of 69.5%, is precisely (C/868MHz) x 0.5 x 0.695 = 116mm. The YouTube video utilized a print featuring item 2948004; mine is largely inspired by that design, so I've classified it as a remix. I made mine significantly more rounded for aesthetic appeal and added arrows to indicate the active element – some individuals appreciate knowing which end is active. The creator of the original video used a Sharpie to denote the active end; I figured it should be incorporated into the print instead, but note that this means you'll need to print a mirrored version so they point in the same direction when placed back-to-back. I employed semi-rigid RG402 coax, similar to what's used on Pagoda FPV antennas, which has a larger diameter. However, I've included files for both this and RG316/ RG174 as per the original design. Here's a link to the source files if anyone wants to remix it: https://cad.onshape.com/documents/e18ef6254b0ae8af3ad3ad60/w/2219b0fc65ec5d5b5f56955a/e/22faf53cfb3ce74e4ed653e4