• FM
  • Beginner
  • 5 min
  • Serial CLI

Recipe · Beginner · FM

How to trace one FM frequency

Use FM trace to observe signal strength at one frequency with a Si4713 module.

FM transmitter module with radio waves.
A practical ESP32 Bit Pirate workflow based on the documented firmware commands.
Step 1

Commands

Run the workflow from the CLI after selecting the matching mode.

Result

What it means

The output confirms that the protocol path is working and gives you a baseline for deeper experiments.

Troubleshooting

  • Run config first to set I2C and reset pin.
  • Use sweep if the frequency is unknown.
  • Keep antenna and wiring stable while comparing readings.

Next steps

  • Run waterfall across the band.
  • Use sweep to find active stations.
  • Only enter broadcast operations under legal low-power lab conditions.

single FM frequency trace FAQ

When should I use trace instead of sweep?

Use sweep to find active parts of the FM band, then trace one frequency when you want to watch signal strength changes over time.

What is trace useful for during FM setup?

Trace lets you watch one selected frequency over time while changing antenna placement, module setup or nearby RF conditions. It is a focused view after a broader sweep.

Can trace help choose a broadcast test frequency?

It can help identify busy local frequencies, but any transmit test must still follow local FM regulations and use only legal low-power lab conditions.

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