Expansion RFEM4G PLUS


RF Explorer RFEM4G PLUS is an expansion module to convert a RF Explorer WSUB1G PLUS into a powerful 4G Combo PLUS Spectrum Analyzer, covering the full range starting at 50KHz up to 4GHz with no gaps or limitations. A future firmware licence will allow to expand the range up to 5.1GHz with no need of additional hardware.

Note: RF Explorer RFEM4G PLUS is an expansion board compatible with RF Explorer WSUB1G PLUS models. It can be assembled in PLUS and PLUS SLIM models only.

For assembly instructions please visit these links:


  • Can be installed in WSUB1G PLUS and WSUB1G PLUS SLIM models
  • Internal LNA amplifier and selectable attenuator for additional power range handling.
  • Low frequency support from 50KHz covering LF, MF, HF, VHF and UHF
  • High frequency support covering all range up to 4GHz with no gaps.
  • Ideal choice for all usable HAM bands.
  • Spectrum Analyzer mode with Peak Max and Hold, Normal, Overwrite and Averaging modes
  • Multi-platform Windows/Linux/MacOS Open Source software and API libraries


  • Frequency band: Right connector: 240 – 4000MHz
  • It can be expanded up to 5.1GHz with additional firmware licence
  • Frequency span in single sweep: 2 – 960MHz
  • Internal selectable LNA 25dB gain
  • Internal selectable Attenuators 30dB and 60dB
  • Wifi Analyzer for the 2.4GHz band
  • Standard SMA 50 ohms connectors
  • Amplitude resolution: 0.5dBm
  • Dynamic range: -125dBm to 10dBm
  • Absolute Max input power: +30dBm
  • Average noise level (typical LNA): -125dBm
  • Frequency stability and accuracy (typical): +-1.0ppm
  • Amplitude stability and accuracy (typical): +-3dBm
  • Frequency resolution: 1Khz
  • Resolution bandwidth (RBW): automatic 2.6Khz to 600Khz
  • Support included for Windows, Linux and MacOS X


  • RF Spectrum Analysis for FM, TV and DTV, ISM, RFID, GSM, 4G/5G, IoT, GPS, Bluetooth
  • WiFi analysis and fine tuning
  • Interference hunting
  • EMC pre-testing
  • RF device tuning (with Signal Generator working as Tracking SNA): See this link for more details

Part List

  • 1 x RF Explorer RFEM4G PLUS Expansion
  • 1 x SMA nut
  • 1 x SMA washer