Building a 137 Mhz QFH antenna

Making a Quadri Filar Helix antenna
 

Original concept
 

F4BPP's improvements

• Use 6 mm diameter raw aluminium full pipe.
• Remove 8 elbows to make the junction with the antenna elements by bending the pipes.
• Only 4 junctions with 8 mm diameter raw aluminium hollow pipe to avoid impedance loss.
• Coaxial cable protected inside the 32 mm PVC pipe.
• Use electric dominoes to connect the cable to the antenna to avoid drilling pipes and ensure better contact between the cable and them.