Unit 4 — Operating Procedures and Calculations
TM-TOOL-008 — Open Handout TM Chapters: Chapter 5, Appendix A ELOs: Execute operating procedure; interpret readings; compute derived quantities Estimated time: 30 minutes (includes 3–4 practice problems)
Step 1: Read the TM
Open TM-TOOL-008. Read Chapter 5 — Operating Procedures and Appendix A completely.
Then come back here.
Chapter 5 Content
5-1 Bird 43 Use
- Insert correct slug for operating frequency and expected power level. Orient flat face for forward or reflected measurement.
- Connect IN to transmitter, OUT to antenna (or dummy load). Key transmitter at target power. Read panel meter. For reflected power: rotate slug 180° (flat face away from meter).
- Compute SWR from P_fwd and P_ref readings.
5-2 Inline Digital Meter
- Insert meter inline between transmitter and antenna (any orientation; no slug rotation needed).
- CYD displays P_fwd (W), P_ref (W), SWR simultaneously. Log readings to SD card if installed.
Appendix A — Reference Formulas
| Bird part | Power | Frequency | Homebrew N2 |
|---|---|---|---|
| 5H | 5W | 25–60 MHz | 6 turns, #67 core |
| 50H | 50W | 25–60 MHz | 10 turns, #67 core |
| 100D | 100W | 400–1000 MHz | Microstrip PCB element |
| 250B | 250W | 2–30 MHz | 10 turns, #43 core |
Key Formulas Summary
Key mathematical relationships from Appendix A:
(See Appendix A in the TM)
Operating Notes
Chapter 5 specifies 5 operating steps.
Measurement discipline: - Always warm up the tool and reference sources before taking readings - Multiple readings improve accuracy — use 3–5 readings and average them - Record every reading with frequency, power level, and settings - A result that seems wrong almost always means a setup error, not a failed tool
Practice Problems
Work these before reading the answer key below.
P4-1. Using the operating procedure from Chapter 5 and the formulas from Appendix A: State the measurement steps you would take to characterize a 40m (7.150 MHz) dipole antenna using the RF POWER METERS — TYPES AND OPERATION. List steps in order.
P4-2. From Chapter 5: what measurement setting or configuration produces the most accurate result with the RF POWER METERS — TYPES AND OPERATION? What is the tradeoff if you use a less accurate setting?
P4-3. Chapter 5 specifies an operating procedure for a specific measurement scenario. State the first three steps of that procedure from memory.
P4-4. Appendix A gives a formula for computing a result from measured values. Pick one formula and compute a worked example using made-up but realistic values. Show all work.
Answer Key — Practice Problems
P4-1. Compare your list to Chapter 5. Steps should include: select range/mode → connect antenna → apply signal or enable source → adjust for null/maximum → read and record → compute result.
P4-2. See Chapter 5. The most accurate setting is usually the narrowest bandwidth or highest resolution, at the cost of longer measurement time or reduced range.
P4-3. See Chapter 5, steps 1–3. Copy exactly then close the TM and state from memory.
P4-4. See Appendix A for the formula. Your arithmetic is correct if your result has the right units and is physically plausible.
Checkpoint
Before proceeding: - [ ] You can state the operating procedure from memory (at least the first 5 steps) - [ ] You can compute the derived quantity from Chapter 5 / Appendix A without looking - [ ] You understand what "an unexpected result" tells you about setup
→ Proceed to Unit 5