Flyable, but VTX antenna is too short and PID tune needs to improvement

Martian IV (3 inch, Walksnail)

Specifications
Frame Realacc Martian IV (3 inch)
FC+ESC HGLRC F4 Zeus AIO 15A
Motors RCX H1304 5000KV
Props Emax Avan 3x2.4x3
GemFan 3x1.6x3
Receiver HappyModel EP1 TCXO (ELRS)
Camera Walksnail Avatar HD Pro Camera
VTX Walksnail Avatar HD Pro
Antenna TrueRC CORE - 45 mm, U.FL, LHCP
Battery Tattu 3S 450 mAh 75C
Turnigy nano-tech 3S 850 mAh 45C
Weight 137 g
180 g (with 3S 450 mAh battery)
M2M 14 cm
Flight time 5+ minutes

Notes

  1. See Martian IV (3 inch) for previous notes regarding the frame and FC
  2. At least Betaflight 4.4.0 is required for Walksnail OSD, 4.5.1 has been used as initially installed version
  3. While the receiver would fit between the FC and VTX, the VTX gets hot enough during normal operations that it would be a bad place for the receiver which has been placed behind the camera instead
  4. Walksnail Avatar VTX doesn't have passthrough holes for 20x20 mm stack (or any other for that matter) but long screws from the bottom of the frame have been used instead for mounting leaving decent space below and plenty about the VTX
  5. Walksnail Avatar HD Pro Kit doesn't come with a camera mount and the hole pattern isn't the same as in RunCam cameras
  6. VTX is rated for 6V-25.2V (2-6S) while FC is 3S and doesn't have a 9V regulator, that's why VTX is directly connected to battery as there's enough headroom for that to not cause problems
  7. The FC doesn't have pads for the beeper resulting in the connector needing to be used for it
  8. Emax Avan 3x2.4x3 feels to be the better prop compared to GemFan 3x1.6x3 and HQProp T3x3x3 which was also tested but concluded to have a too high pitch, Gemfan Hurricane 3020-3 hasn't been tested

Wiring