Calibration and Backup

Calibration and Backup

Caution

This is the most important page on the wiki. If you skip everything else, read this. Calibration data is per-unit — your radio's factory tuning is unique. Lose it without backup, and you have a radio that transmits off-frequency, mis-reports signal strength, and may exceed power limits.

• What is calibration?
• Why back up calibration first
• Making a backup
• Restoring calibration
• Diffing two calibration dumps
• Best-practice habits

What is calibration?

The calibration region of EEPROM is a small (~512 bytes) area near the top of memory that contains values measured at the factory for this specific unit:

• Frequency calibration — the exact crystal offset that makes 145.000 MHz be 145.000 MHz
• TX power calibration — DAC values for each band/power-level combination so output power matches the label
• RX gain / S-meter calibration — analog gain and S-meter thresholds
• Squelch calibration — RSSI thresholds per band

These values are measured once at the Quansheng factory using lab equipment (signal generator, RF power meter). They cannot be re-derived without the same equipment. If you lose them and don't have a backup, the radio still works — but it transmits a few kHz off, the S-meter is wrong, and TX power can be significantly higher or lower than displayed (potentially out-of-spec).

Why back up calibration first

Three scenarios where calibration can be lost or corrupted:

1. Firmware flash — the calibration region is normally preserved across a flash, but a bad/interrupted flash, or a firmware that overwrites the wrong sectors, can destroy it.
2. Bad EEPROM write — if you're scripting and accidentally write zeros to the calibration region.
3. Hardware failure — rare, but the EEPROM cell can degrade.

Important

Habit to internalise: before any write or flash operation, dump the calibration to disk and store it somewhere durable (cloud, second machine, USB stick). It's a 5-second operation that has saved many radios.

Making a backup

GUI

1. Open the Calibration tab.
2. Click Read calibration. The region is fetched from the radio and shown as a hex view.
3. Click Save calibration to file…. Default filename includes a timestamp: calibration_<radio>_<timestamp>.bin.
4. Save it somewhere durable. Do this for every radio you own — calibration is per-unit, not per-model.

You should also save the full EEPROM image while you're at it (Dashboard → Read EEPROM → Save image). It contains the calibration plus everything else (channels, settings, etc.), giving you a complete restore point.

CLI

# Calibration only
python -m quansheng_toolkit dump-calibration -o calibration_$(date +%Y%m%d_%H%M%S).bin

# Full EEPROM (recommended)
python -m quansheng_toolkit read -o eeprom_$(date +%Y%m%d_%H%M%S).bin

Tip

Name your backups with the radio's serial number (printed on the sticker under the battery): calibration_K5V3_SN12345_20260507.bin. If you have multiple radios of the same model, this is the only way to keep them straight after a year.

Restoring calibration

Warning

Restore only a calibration that came from this exact radio. No two radios share the same calibration — restoring another unit's calibration produces a radio that's worse than no calibration at all (you've replaced its factory tuning with one that was correct for a different physical unit). The toolkit's restore performs a byte-count and target-metadata check, but it cannot detect "wrong unit, same model".

GUI

1. Open the Calibration tab.
2. Click Load calibration from file…. The toolkit opens the file and shows a confirmation dialog with:
   • File path
   • Byte count
   • Target model encoded in the file (e.g. k5_v3)
   • Comparison against the live radio's target
3. Confirm. The calibration is written and read back for verification.

CLI

python -m quansheng_toolkit restore-calibration --file calibration_K5V3_SN12345_20260507.bin --yes-i-understand

The --yes-i-understand flag is mandatory.

Diffing two calibration dumps

Useful for confirming a flash didn't touch calibration:

1. Dump calibration before the flash → cal_before.bin
2. Flash firmware
3. Dump calibration after the flash → cal_after.bin
4. In the toolkit: Calibration → Diff two files… → pick the two files

The toolkit shows a byte-by-byte diff. If anything changed, the affected regions are highlighted.

CLI equivalent:

python -m quansheng_toolkit diff-calibration --a cal_before.bin --b cal_after.bin

Best-practice habits

Tip

The toolkit is fully offline — every operation works without an internet connection. Take advantage of that for backup hygiene: keep a USB stick with quansheng-toolkit.exe plus a folder of per-radio backups, and you have a complete portable maintenance kit you can carry to a hamfest or a remote site.

A short checklist that prevents most disasters:

• ✅ First-day ritual on a new radio: read full EEPROM + read calibration, save both with the serial number in the filename.
• ✅ Before any firmware flash: repeat the above. Every time. No exceptions.
• ✅ Before any "experimental" CSV import: save a full EEPROM backup. CSV imports are reversible but it's quicker to restore than to debug.
• ✅ After any firmware flash: dump calibration again and diff against the pre-flash dump. Should be byte-identical. If not, the flash damaged calibration — restore from backup immediately before doing anything else.
• ✅ Annually: re-export your channel CSV. If the radio dies, you need that file to set up a replacement.

Caution

If you restore a calibration backup and the radio still misbehaves, do not flash again trying to fix it. You've already exhausted the easy options. Open an issue with the diff between your pre-flash and post-flash calibration dumps; we may be able to identify what was corrupted.

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Next: CLI Reference for headless and scripted workflows.