Unit 5 — Calibration and Verification

TM-TOOL-004 — Open Handout TM Chapters: Chapter 6, Chapter 7 ELOs: Calibrate the RF DUMMY LOADS — CONSTRUCTION AND USE; verify performance against acceptance criteria; complete calibration log Estimated time: 45 minutes (actual lab work required)

Step 1: Read the TM

Open TM-TOOL-004. Read Chapter 6 — Calibration and Chapter 7 — Verification and Acceptance completely.

Then come back here.

Chapter 6 — Calibration Content

1. Calibrate NanoVNA with SOLT at the measurement connector (not at the NanoVNA port).
2. Sweep 1.8 MHz to 450 MHz. Record SWR at 1.8, 3.5, 7, 14, 21, 28, 50, 144, 222, 432 MHz.
3. Acceptance criterion: SWR <1.1:1 at 1.8–50 MHz; SWR <1.3:1 at 50–150 MHz; SWR <1.5:1 at 150–450 MHz.
4. Record DC resistance: must be 49.0–51.0Ω.

Chapter 7 — Verification Content

1. Thermal test (100W load): apply 100W (from dummy transmitter or keyed transceiver) for 60 seconds. Heatsink must not exceed 80°C (use contact thermometer or thermal camera).
2. Thermal test (oil loads): apply rated power for 10 minutes. Oil must not bubble or emit smoke. If oil reaches 80°C, reduce power or duty cycle in future use.
3. Post-thermal SWR check: repeat SWR sweep immediately after thermal test. SWR must not have increased by more than 0.1 compared to cold measurement.
4. Log: date, resistors used, DC resistance, SWR at key bands, thermal test result, operator.

Calibration vs. Verification — Distinction

Calibration (Chapter 6): active adjustments to bring the tool within specification. You are permitted to adjust, tweak, and repeat until the criterion is met.

Verification (Chapter 7): independent confirmation that the calibration succeeded. No adjustments are permitted during verification. If a verification check fails, you return to Chapter 6, not to Chapter 7.

Acceptance Criterion

A criterion found in Chapter 6: 51.0Ω. Confirm the exact criterion in the TM.

Write the exact criterion from the TM here before you start the lab:

Lab Checklist

Work through each item in sequence. Do not skip steps.

• [ ] All required equipment gathered and ready
• [ ] Equipment warmed up per TM requirements
• [ ] All Chapter 4 setup steps verified complete
• [ ] Chapter 6 calibration performed (all steps)
• [ ] Calibration criterion met (recorded below)
• [ ] Chapter 7 verification performed (all steps, no adjustments)
• [ ] All verification criteria passed
• [ ] Calibration log entry completed

Calibration Log Entry

• [ ] Date
• [ ] Equipment used
• [ ] Measurements taken
• [ ] Results vs. criteria
• [ ] Operator name

Record your results:

Self-Check Questions

SC5-1. What is the acceptance criterion for this calibration (from Chapter 7)?

SC5-2. During verification, one reading fails. What is the correct action per the TM?

SC5-3. List the items required in a calibration log entry per Chapter 7.

SC5-4. What is the difference between calibration and verification in this context?

SC5-5. If the tool passes all Chapter 7 checks, what does that tell you about its current state?

Answer Key

SC5-1. See Chapter 7. The criterion is stated as a specific value with units.

SC5-2. Stop verification. Return to Chapter 6 and re-calibrate. Diagnose the cause before re-adjusting.

SC5-3. See Chapter 7, last numbered step. The log items are listed there.

SC5-4. Calibration allows adjustments; verification does not. Verification is independent confirmation.

SC5-5. It tells you the tool is performing within its specified accuracy at this time. It does not tell you how long it will remain in calibration — periodic re-calibration is required.

Checkpoint

You are ready for the final assessment when you can: - [ ] State the acceptance criterion from memory - [ ] State the difference between calibration and verification - [ ] State the required log items from memory

→ Proceed to Final Assessment