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SXceiver SDR Transceiver — Optimized for the 70 cm Amateur Radio Band

· 3 min read
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SXceiver is a software-defined radio transceiver optimized for the 70 cm (430–440 MHz) amateur radio band.

Sold as a kit, SXceiver includes a printed circuit board with all SMD components pre‑mounted, and a through‑hole pin header for Raspberry Pi connection.

Key Features​

  • Optimized for the 70 cm amateur radio band (430–440 MHz)
  • Full‑duplex transmit and receive
  • Sampling rate: 25 kHz to 600 kHz
  • 0.5 ppm TCXO for excellent frequency stability
  • SoapySDR support — works with a wide range of SDR applications
  • Timestamping for synchronized RX and TX data streams

Specifications​

SXceiver is built around the Semtech SX1255 I/Q transceiver chip and connects to Raspberry Pi via I2S and SPI interfaces.

Frequency Range​

ParameterValue
Guaranteed tuning range400–510 MHz
Typical extended range~360–550 MHz (most units)
RF matching networkOptimized for 430–440 MHz

Sampling Rate, Bandwidth and Bit Depth​

  • Supported sampling rates via SoapySX driver: 25 kHz, 50 kHz, 75 kHz, 150 kHz, 300 kHz, 600 kHz
  • The SX1255 uses 1‑bit sigma‑delta ADCs for I and Q signals, running at a fixed 38.4 MHz clock
  • High‑rate 1‑bit signals feed digital decimation filters to output lower‑rate, higher‑bit‑depth data
  • Effective number of bits (ENOB) depends on sampling rate and gain settings
  • Transmit signals pass through interpolation filters and sigma‑delta modulators before I/Q DACs
  • Slow filter rolloff limits usable bandwidth to roughly half the sampling rate

Other RF Specifications​

ParameterValue
Transmit powerUp to 4 dBm PEP (can be boosted with external PA)
Frequency reference0.5 ppm TCXO

Additional Functions​

  • Full‑duplex operation with precise timestamp synchronization for time‑critical digital modes (TDD, FDD, TDMA)
  • Controls external RX/TX switching synchronized with transmit streams, ideal for fast‑switching TDD modes

Supported Raspberry Pi Models​

Tested on:

  • Raspberry Pi Zero 2 W
  • Raspberry Pi 4
  • Raspberry Pi 2

Most other models should work but are untested. Requires a 40‑pin GPIO interface — not compatible with legacy 26‑pin Raspberry Pi 1 models. Older, slower boards may lack performance for some applications.

Compatible Software​

Tested applications:

SoftwareUsage
SDR++, GqrxGeneral reception
QuiskAM/FM/SSB/CW transceiver (minor patch required)
MMDVM (experimental fork)FM/DMR/M17 repeater/hotspot
HamTetra DMO (highly experimental)TETRA DMO repeater
analog_linear_repeater.pyAnalog linear repeater

This is not a complete list. Thanks to the SoapySDR interface, SXceiver works with many existing applications.

Authored on 2026-05-15 · Document Version: 7a3f9c2 · Last Revision: 2026-05-15