Unit 5 — Verification and Logging

TM-CAL-001 — Open Handout TM Chapters: Chapter 6, Chapter 7 ELOs: Apply adjustments; perform independent verification; produce calibration log Estimated time: 45 minutes (hands-on lab)

Step 1: Read the TM

Open TM-CAL-001. Read Chapter 6 and Chapter 7 completely.

Then come back here.

Chapter 6 — Tuning and Adjustment

6-1. ADJUSTING A FREQUENCY COUNTER REFERENCE

Identify the trimmer capacitor (TCXO) or voltage adjustment pin (VCTCXO/OCXO) in the frequency counter.
While monitoring the counter reading against WWV, adjust the trimmer in small increments until the displayed frequency matches expected value.
Allow 5 minutes after each adjustment for thermal stabilization before reading final value.
Do not over-adjust. Most TCXO trimmers have a range of ±10 ppm.

6-2. ADJUSTING A SIGNAL GENERATOR

Set the generator to 10.000 MHz and connect output to the frequency counter.
Compare counter reading against WWV-calibrated reference.
Adjust the generator's frequency calibration control (typically a front-panel vernier or internal trimmer) to match.
Lock the calibration control (if equipped) and record the setting.

Chapter 7 — Verification

7-1. INDEPENDENT VERIFICATION

After calibration, tune to a second WWV frequency (e.g., if calibrated on 10 MHz, verify on 5 MHz).
Repeat the frequency measurement. Error should be 5 ppm | | Crystal counter (no temp comp) | 50 ppm | | Signal generator | 20 ppm | | Receiver VFO | 500 Hz |

Calibration vs. Verification

These are two different things:

Calibration (Chapter 5): You apply reference inputs and record what the instrument reads. You may adjust the instrument during this process. The result is a set of measurements taken while you are actively tuning.

Verification (Chapter 7): After all adjustments are complete, you perform an independent confirmation measurement. You do not adjust during verification — you are testing whether the calibration held.

The TM states a verification criterion of: 5 ppm |. Confirm the exact wording in Chapter 7.

If verification fails, you do not re-adjust and re-verify in one step. You return to Chapter 5, re-calibrate, and then re-verify from scratch.

Lab Checklist

Work through this with equipment in hand. Check each box when complete.

[ ] Chapter 4 setup complete
[ ] Chapter 5 calibration procedure complete
[ ] Any adjustments applied per Chapter 6
[ ] Chapter 7 verification measurement performed
[ ] Verification criterion met
[ ] Calibration log entry completed:
[ ] Date
[ ] Instrument type and model
[ ] TM number and procedure
[ ] Reference standard used
[ ] Measured values
[ ] Errors (% or ppm)
[ ] Pass/Fail result
[ ] Operator name

Self-Check Questions

SC5-1. What is the verification acceptance criterion per Chapter 7? State it with units.

SC5-2. What is the difference between the Chapter 5 calibration and the Chapter 7 verification?

SC5-3. Your Chapter 7 verification fails. What is the correct next step per the TM?

SC5-4. List the required entries in the calibration log.

SC5-5. Why must the log be completed before the calibration is considered finished?

Answer Key

SC5-1. See TM Chapter 7. Copy the criterion exactly with units and section number.

SC5-2. Chapter 5 is the active calibration — you apply references and may adjust. Chapter 7 is an independent confirmation after all adjustments are locked in — no further adjustment during verification.

SC5-3. Return to Chapter 5 and re-calibrate. Do not re-adjust and re-verify without re-doing the full calibration procedure.

SC5-4. See TM Chapter 7. List every item the TM specifies.

SC5-5. A calibration with no record did not happen in any traceable sense. The log is the evidence that the procedure was followed, the results were within specification, and who performed it.

Checkpoint

TLO-1 is complete when: - [ ] Verification criterion met (Chapter 7) - [ ] Calibration log entry completed with all required fields - [ ] You can explain the difference between calibration and verification

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