Shack Book Antenna Calculator: a free Claude skill

A small skill that works out starting lengths for dipoles and verticals in feet and meters, explains how to trim for low SWR, and checks the frequency against your license.

• Dipoles, verticals and radials
• Trim-for-SWR steps
• Privilege and safety check

Made by Shack Book, part of What If Labs.

Install it

1. Download shack-book-antenna-calc.zip (don’t unzip it).
2. In Claude on the web or desktop, open Customize, then Skills, click +, choose Upload a skill and pick the ZIP.
3. Make sure code execution is on in Settings, Capabilities. It works on any Claude plan, including the free one.
4. Ask Claude something in plain words. It picks the skill up on its own.

Using Claude Code instead? Copy this folder into ~/.claude/skills/.

Try a free tool first

No Claude needed: the Dipole Antenna Length Calculator runs in your browser and shows its working.

Want the whole thing?

The Shack Book Ham Companion is $19, one time, with a 14-day refund. Study, set up, operate and log.

• Exam study and practice drills
• Privileges and band plans
• Antenna, SWR and feedline math
• Station planning
• FT8 and digital mode setup
• UTC logs with ADIF fields
• POTA, SOTA, contests and nets
• Updates for a year

License

MIT. Use it, change it, share it. Please keep the credit to Shack Book.