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antennas:qfh

QFH Antenna Build

From Scott - 2M0VSR:

Credits

Inspired by this build: https://tf1ez.com/qfh-antenna-build/

Summary Instructions

The above link has a better guide but the TLDR version is:

  • Generate and print the paper templates based on the type of PVC pipe you have. Use: https://jcoppens.com/ant/qfh/calc.en.php
  • Tape the cut-outs onto the PVC pipe, making due they are aligned down the pipe.
  • Drill out the holes. The centre ones are not strictly needed but you may find it useful to use some wooden dowel rods to support the banding.
  • Cut the threaded rods down to size based on the calculator. Leaving them a little long won't do any harm.
  • Put the threaded rods though and use a washer/nut against the PVC pipe to hold in place.
  • Cut the Banding so that it stretches to the opposite bottom rod. I'd leave a bit extra and trim.
  • Use 2 nuts/washers to lock in place the banding on each end.
  • Attach the Coax ends to the top of the antenna and run it down the tube. Tie it off to the bottom with some zip ties for strain relief.

Notes:

  • You can use low gauge wire as an alternative to banding but it's much more difficult to work with and get aligned well. I used 10mm earth wire for an earlier build and it worked ok.

Parts List

  • - PVC Pipe (55mm, 1meter or similar)
  • - Galvanised Steel Banding - Screwfix
  • - M4 Threaded Rods (x4) Amazon
  • - M4 Nuts (x24) Amazon
  • - M4 Washers (x24) Amazon
  • - Good Quality Coax. (Messi Hyperflex 5 / Ultraflex 7) ML&S

Whole thing can be built for less than ~£25. Less if you shop around / scavenge a bit more.

antennas/qfh.txt · Last modified: 2024/04/24 19:15 by 2m0vsr