A 30m loading coil for the MC-750 or MA-12 antenna

This design is for a loading coil to get the MC-750 or MA-12 antenna on to 30m / 10 MHz amateur band more efficiently than with the 40m coil supplied.

See https://www.george-smart.co.uk/2026/01/homebrew-30m-coil-for-the-mc-750-ma-12-antenna/ for more information

TLDR:

• Print 2 end caps, 1 loading coil ideally in ASA (lowest dielectric loss, but I used PETG).
• Use a brass M10 nut and bolt for the end caps.
• Wind 7.5 turns on the coil with 1mm diameter wire (about 1.2 metres long).
• Carefully solder to nut and bolt, avoiding melting the former.
• Pull main antenna whip out all but the bottom section & adjust for minimum SWR.

Build images courtesy of Rob M0VFC.

George M1GEO