Nec2 Antenna

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What is mcp-nec2-antenna?

mcp-nec2-antenna is an MCP server that wraps NEC2 (Numerical Electromagnetics Code, version 2). The classic method-of-moments wire-antenna solver, so an LLM agent can design, sweep, and analyze HF / VHF / UHF antennas through plain-English tool calls.

Drive it from any MCP client (Claude Desktop, Claude Code, Codex CLI) or call the NEC2C binary directly via the same card-deck export. Five parameterized antenna geometries (dipole, Yagi-Uda, ground-plane vertical, full-wave loop, inverted-V) compile to NEC2 GW/EX/FR/RP cards, solve with the nec2c reference engine, and return impedance, VSWR, gain, and front-to-back from a single tool call.

What mcp-nec2-antenna does well:

• AI-native via MCP. First-class Model Context Protocol server with 9 tools. Any Claude / LLM agent can drive it.
• Reference engine. Uses the canonical NEC2C C implementation. The same solver behind 4nec2, xnec2c, and antenna textbooks.
• Parameterized geometries. Five built-in wire antennas with closed-form initial sizing; the agent fills in band + height + element count and gets a ready-to-solve deck.
• Three ground models. free-space, perfect ground, real (Sommerfeld) ground: picked per geometry.
• AGPL-3.0-or-later. Modifications shared back if served over a network.

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Quick start

Install

NEC2C must be on PATH first:

# Ubuntu/Debian
sudo apt install nec2c

# macOS
brew install nec2c

# Arch Linux
yay -S nec2c

Then:

git clone https://github.com/RFingAdam/mcp-nec2-antenna.git
cd mcp-nec2-antenna
uv pip install -e .

Wire it into your MCP client

Claude Code:

claude mcp add nec2-antenna -- uv run --directory /path/to/mcp-nec2-antenna mcp-nec2-antenna

Codex CLI:

codex mcp add nec2-antenna -- uv run --directory /path/to/mcp-nec2-antenna mcp-nec2-antenna

Raw config (Claude Desktop):

{
  "mcpServers": {
    "nec2-antenna": {
      "command": "uv",
      "args": ["run", "--directory", "/path/to/mcp-nec2-antenna", "mcp-nec2-antenna"]
    }
  }
}

Then ask your assistant in plain English:

"Design a 5-element Yagi for 435 MHz at 10 m height, simulate it, and tell me the gain and front-to-back."

The agent calls nec2_create_yagi followed by nec2_simulate, and reports impedance, VSWR, and radiation pattern.

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Tools

Tool	Purpose	Key arguments
nec2_create_dipole	Half-wave horizontal dipole	name, frequency_mhz, height_m
nec2_create_yagi	Yagi-Uda directional beam	name, frequency_mhz, num_elements, boom_height_m
nec2_create_vertical	Quarter-wave vertical w/ radials	name, frequency_mhz, num_radials
nec2_create_loop	Full-wave quad loop	name, frequency_mhz, height_m
nec2_create_inverted_v	Inverted-V dipole from a single mast	name, frequency_mhz, apex_height_m, droop_deg
nec2_simulate	Run NEC2 sweep: Z, VSWR, gain, pattern	antenna_id, frequency_start/stop_mhz, steps
nec2_get_nec_cards	Export raw NEC2 card deck (for 4nec2/xnec2c)	antenna_id
nec2_list_antennas	List antennas in the current session	none
nec2_list_antenna_types	Show built-in antenna types + characteristics	none

Full tool reference in docs/tools.md.

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What it solves

Antenna	Typical gain	Pattern	Best for
Dipole	2.15 dBi	Omnidirectional	General purpose, portable
Yagi-Uda	7–15 dBi	Directional	DX, satellites, weak-signal work
Vertical	0–2 dBi	Omnidirectional	Mobile, limited real estate
Loop	3–4 dBi	Bidirectional	Low-noise receive, DX
Inverted-V	2 dBi	Omnidirectional	Single-mast portable

Ground models: free-space, perfect (PEC), and real (Sommerfeld two-medium). Pattern step is configurable; default is 5° azimuth/elevation.

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Workflows

mcp-nec2-antenna fits in the following eng-mcp-suite workflow bundles:

• rf-design: closed-form trans-line synthesis (lineforge) + wire-antenna MoM (this server) + circuit/filter sim (mcp-ltspice-qucs).
• antenna-bench: antenna design + EMC limit lookup (mcp-emc-regulations) before lab measurement.

See the suite manifest for the full list of sibling MCPs and bundle definitions.

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Documentation

• Quick Start: install through first call.
• Tool reference. Every MCP tool, every argument.
• Usage examples: practical end-to-end walkthroughs.
• Architecture: how this MCP fits in eng-mcp-suite.

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Part of eng-mcp-suite

_{This MCP server is part of}

eng-mcp-suite

_{An open umbrella for engineering MCP servers across RF, EMC, PCB, signal integrity, EM simulation, and lab test. Same brand, same docs structure, designed to compose. See the full catalog or jump to a sibling:}

Domain	Sibling MCPs
RF / Transmission lines	lineforge
Circuit + filter sim	mcp-ltspice-qucs
PCB / SI	mcp-pcb-emcopilot
EMC regulatory	mcp-emc-regulations
EM simulation (3D)	mcp-openems
Diagrams	drawio-engineering-mcp
Lab gear	copper-mountain-vna-mcp

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Contributing

Contributions are welcome.

1. Pick a GitHub issue.
2. Fork + branch (feature/your-thing or fix/your-bug).
3. Run the local check suite:

   uv run pytest
   

4. Open a PR: link the issue, request review.

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License

AGPL-3.0-or-later. Relicensed from Apache-2.0 in v0.2.0 to align with the eng-mcp-suite toolkit-wide AGPL move. The underlying NEC2 engine is public-domain US-government code; this wrapper is AGPL-3.0-or-later and is independent of NEC2's public-domain status.

Trademarks and brand assets

This project is not affiliated with, endorsed by, or sponsored by Lawrence Livermore National Laboratory or any distributor of NEC2. "NEC2" is used here only to identify the electromagnetics code this project interoperates with.

The project name and the logo files in this repository are not part of the licensed work. The licence above grants no permission to use them, except as needed to describe the origin of the work.

Acknowledgments

• Gerald J. Burke (LLNL): original NEC2 Fortran (1981, public domain).
• Neoklis Kyriazis (5B4AZ): NEC2C C port, the reference engine this server invokes.
• The MCP working group: for the Model Context Protocol specification.