The 4x1 Quad-Band Module is an auxiliary RF front-end designed to extend the capabilities of the GNSS-SRP FOUR platform, while maintaining compatibility with other 4×4 MIMO SDR systems such as the FMCOMMS5.

This module enables single-antenna, simultaneous multi-band GNSS reception, supporting both upper (L1/E1) and lower (L2/L5/E5/E6) frequency bands through an integrated frequency conversion architecture.

1-channel quad-band GNSS module diagram

The design incorporates dual RF mixers that, combined with the multi-transmitter capability of the GNSS-SRP FOUR, allow the generation of configurable local oscillator (LO) tones directly from the SDR. This enables flexible frequency translation, allowing reception of up to four concurrent GNSS bands, each with bandwidths of up to 56 MHz.

System configuration and control are fully supported via WaveMasters open-source host drivers, with integration available for both GNSS-SDR and GNU Radio environments.

When paired with the GNSS-SRP FOUR, the module operates in a plug-and-play configuration, powered directly through the integrated bias-T. When used with third-party SDR platforms, an external power supply may be required depending on the system configuration.

RF Frequency Mapping

Connector Type Frequency Range GNSS Bands Conversion
ANT1 Input 1164–1300 / 1520–1615 All bands —
RX1 Output 1520–1615 Upper band Direct
RX2 Output 1520–1615 Lower band Mix1: (1164–1300) + LO1 → 1520–1615
RX3 Output 1164–1300 Lower band Direct
RX4 Output 1164–1300 Lower band Mix2: (1164–1300) + LO2 → 1164–1300
LO1 Input 315–356 — External LO
LO2 Input 70–136 — External LO

Key Features

  • Single-antenna quad-band GNSS reception,
  • Simultaneous reception of up to 4 GNSS bands,
  • Integrated dual-mixer architecture,
  • LO generation using SDR transmit channels (no external synthesizer required),
    • Up to 56 MHz bandwidth per band.
  • Compatible with:
  • Bias-T powered (plug-and-play with GNSS-SRP FOUR),
  • Open-source software support:

Expected availability: Q4-2026

Updated: