• SDR
  • Intermediate
  • 10 min
  • Web ESP SDR

Recipe · Intermediate · SDR

How to reduce noise and calibrate ESP SDR

Reduce the background with the antenna connected, or collect an optional noise-only receiver reference.

Signal diagnostics and troubleshooting illustration.
Compare the original and corrected views to check what the reference removes.
Step 1

Start and connect the SDR adapter

Switch to USB mode and open Adapters:

mode usb
adapters

Select ESP-SDR Raw 2.4GHz. The board reboots into SDR mode.

Close the terminal, open Web ESP SDR and click Connect. Select the board’s USB port.

Set the frequency or scan range and manual gain, then start a stream or scan.

Step 2

Reduce background noise

Keep the antenna connected and click Reduce noise, preferably while the wanted signal is inactive. Wait for learning to finish, then click again to compare. Signals present during learning may also be reduced.

Step 3

Calibrate the receiver — optional

Open Advanced settings → Calibration → Calibrate…. Disconnect the removable antenna or terminate the RF input, then click Input ready · calibrate. Keep the input noise-only throughout the measurement.

When prompted, reconnect the antenna and click Antenna reconnected. In Live SDR, choose Display → Signal view: Corrected. Use Remove calibration to compare.

Result

What success looks like

The corrected view can make activity easier to see. Levels remain relative, not calibrated received power in dBm.

Troubleshooting

  • Wanted signal disappears: Disable Reduce noise or remove calibration, then learn a reference without that signal.
  • Receiver overloaded: Lower manual gain and collect a new reference.
  • Fixed PCB antenna: Use Reduce noise unless you can provide a noise-only input for receiver calibration.

ESP SDR FAQ

When should I repeat the reference?

After restarting the stream or scan, or changing frequency, range, receiver settings, FFT window or Tune diversity.

Does Reset history remove calibration?

No. It clears accumulated traces and keeps the receiver reference.

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