Quadrifilar Helix Antenna

I followed Andrew McNeil’s design for a 5.8GHz Quadrifilar Helix Antenna. This was to replace a crappy omni whip antenna that came with an RC852 video rx.

I ordered some semi rigid coax from ChinaRF on eBay and I used some earth wire from some scrap 2C+E i had laying around. I tried to straighten it as best i could!

Bending the shape of the lobes was harder than expected. I posted on reddit and someone suggested using a 3D Printer to create a jig. One for the future i think!

It works better than expected. I hooked it up to my HackRF and compared the received signal from my FPV racing quad. With the original omni i was seeing peaks at -65dbm but with this i reliably get to -55dbm in the same test conditions and subjectively much better signal when the quad is moved around.