Universal FT240 Balun / Unun Box

Box for a balun or unun of your desired configuration wound on a FT240 toroid.

Features:

• M5 bind terminals with winged nuts used to quickly connect or disconnect antenna radials.
• The ring with 8 holes in the middle of the bottom part is used to secure the toroid in place with zip ties. Pass the zip ties through the holes.

Print in PETG, PLA or ABS. Rectilinear infill. Archimedean chords for bottom layer. The loop might require supports.  The screw holes use sacrificial layers that will have to be drilled out with a 4 mm drill.

BOM: 

• For securing the lid:
  • 4x M4x30 screws
  • 4x M4 nuts
• Socket connection:
  • Type N socket, or any other socket you prefer, with 4 mounting holes and 25.4 mm mounting hole pitch
  • 4x M3x10 screws
  • 4x M3 nuts
  • 1x M3 O-type of fork type crimp terminal (OT 1-3 used in the photos) 
• Bind terminals:
  • 2x M5x20 screws
  • 4x M5 washers
  • 2x M5 nuts
  • 2x M5 winged nuts
  • 2x M5 O-type or fork type crimp terminal (SC 1.5-5 used in the photos)
    • The same crimp terminals can be used on the antenna radials
• Zip ties to secure the toroid
  • pass them through the holes in the central printed ring

As per request I have also added a version that fits two cores scacked on top of each other. This version will require M4x50 screws for the lid.