Unit 2 — Construction and Materials

TM-TOOL-003 — Open Handout TM Chapter: Chapter 3 ELOs: Identify required components and materials; understand component selection criteria Estimated time: 20 minutes

Step 1: Read the TM

Open TM-TOOL-003. Read Chapter 3 — Equipment and Materials completely.

Then come back here.

Chapter 3 Content

3-1 Python Environment

Python 3.10 or later is required. Install dependencies:

pip install -r requirements.txt Core packages: numpy, scipy, pandas, matplotlib, fastapi, uvicorn, pydantic, httpx, tqdm, requests. Optional: scikit-rf (Smith chart), plotly (interactive 3D patterns).

3-2 NEC2 Engine Installation (Debian/Ubuntu)

sudo apt install nec2c Verify: nec2c --version should return without error. The runner (nec_runner.py) auto-detects available engines in the order: nec2c, nec4, necpp, 4nec2.

Component Selection

Review the equipment and materials list in Chapter 3 carefully.

Before building, verify every item on the materials list. Key considerations: - Use the specified component types — substitutions may affect performance or frequency coverage - Non-inductive components are required in RF circuits; standard wirewound resistors are unsuitable - Toroids and ferrite cores are frequency-specific; use the specified core material (#43, #61, #67, etc.) - Connector types affect impedance — match the specified connector to avoid SWR errors

The quality of your materials sets the ceiling on the tool's performance.

Self-Check Questions

SC2-1. List the three most critical components or materials specified in Chapter 3. Why are they critical?

SC2-2. Does Chapter 3 specify non-inductive resistors? If so, where are they used and why does it matter?

SC2-3. What connector type(s) does Chapter 3 specify, and what is the frequency/power justification?

SC2-4. Does Chapter 3 specify a particular ferrite core material or type? What is its significance?

SC2-5. What would be the consequence of substituting a standard wirewound resistor for a non-inductive type in an RF application?

Answer Key

SC2-1. See Chapter 3. Identify items with specific part numbers, special materials, or critical tolerances — these are the ones that most affect performance.

SC2-2. See Chapter 3. Non-inductive types are used wherever standard inductive wirewound resistors would add series inductance that degrades high-frequency performance.

SC2-3. See Chapter 3. SO-239, N-type, BNC, and SMA each have different frequency and power ratings.

SC2-4. See Chapter 3. Ferrite #43 is for 1–100 MHz; #61 for 10–200 MHz; #67 for 50–500 MHz. Wrong material = wrong permeability = wrong coupling.

SC2-5. A wirewound resistor has several microhenries of series inductance. At HF and VHF, this adds inductive reactance proportional to frequency, destroying the resistor's value as a termination or load.

Checkpoint

Before proceeding: - [ ] You have read Chapter 3 completely - [ ] You can name the critical components from memory - [ ] You understand why non-inductive and correct ferrite materials are required

→ Proceed to Unit 3