RF422 868 MHz SRD860 Radio


The RF422 is an 868 MHz SRD860 radio designed to provide license-free operation for wireless serial communications in Europe. The RF422 transmits data at 10 kbps with a maximum power of 25 mW, and it employs listen-before-talk (LBT) and adaptive-frequency-agility (AFA) to provide a robust link of up to 5 km (line-of-sight). The RF422 supports point-to-point and point-to-multipoint datalogger communications and PakBus repeater operation.

The RF422 is part of the RF407-series of radios that includes:

  • RF407: North America (FCC & IC), 902 to 928 MHz
  • RF412: Australia (ACMA RCM), 915 to 928 MHz
  • RF422: Most of Europe and some of Asia (ETSI), 863 to 870 MHz

Benefits and Features

  • Does not require individual operational license in Europe
  • Robust serial communication, optimized for PakBus networks
  • Low power (< 2 mA idle) during periods of inactivity
  • Supports point-to-point with RF retries and point-to-multipoint operations
  • Remote diagnostics using PakBus node operations
  • Operational power can be supplied over USB when attached to PC

Campbell Scientific recommends installing the RF422 868 MHz radio at least 200 m (656.2 ft) from any 4G LTE cellular transmitter, including towers and cellular modems/gateways.


Front tilt view
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Radio Type SRD860, LBT+AFA
Restrictions See REC70-03E, CEPT recommendation on the use of SRD.
Compliance Listen before talk (LBT) and automatic frequency agility (AFA) to comply with ETSI duty cycle requirements. Radio communication effective duty cycle = (number of channels * 100) / 3600.
Channel Capacity 30 channels (default), software configurable for the purpose of meeting local regulations; 10 sequences for reducing interference through channel hop.
Frequency 863 to 870 MHz
Power Output 2 to 25 mW (software-selectable; assuming 2 Bi antenna gain)
Receiver Sensitivity -106 dBm
Data Rate 10 kbps
Link Throughput 8 kbps
Antenna Connector Reverse Polarity SMA (RPSMA) jack
LEDs Red TX/PWR and green RX
RS-232 Baud Rate 1200 to 115200 bps
CS I/O Modes SDC 7, 8, 10, 11, and ME master
Power 9 to 16 Vdc
Power Connector 2.5 mm dc power jack
Operating Temperature Range -40° to +70°C
  • CE
  • ETSI EN 300 220-2 V2.3.1
Current Required
  • Transmit: 25 mA (25 mW TX Power)
  • Receive: 15 mA
  • Sleep: 0.5 mA (depending on power saving mode)
Communication Ports
  • RS-232 9-pin D female
  • CS I/O 9-pin D male
  • USB Type B jack
Dimensions 11.1 x 6.9 x 2.7 cm (4.4 x 2.7 x 1.1 in.)
Dimensions are from the tip of the antenna connector to the other side of the case, and from the bottom of the case to the top of the DB9 connector jack screw. The width includes the thickness of the screw heads on the screws that hold the case together.
  • 136 g (4.8 oz) without "Ships With" items
  • 283.5 g (10 oz) with "Ships With items

LBT+AFA Performance

Channel Spacing 100 kHz
Receiver Bandwidth 150 kHz
Modulation Bandwidth < 300 kHz
LBT Threshold < -88 dBm
TX on Time < 1 s


The RF422 is over-the-air compatible with other RF422-based products. The RF422 can only communicate wirelessly with other RF422 radios and other Campbell Scientific products that have the "-RF422" option. 

Datalogger Considerations

Datalogger RS-232 CS I/O
CR300 *
Mixed-array dataloggers **

*Use a 18663 null modem cable.
**It is possible to connect a mixed-array datalogger (e.g., CR10, CR10X, CR23X, 21X, CR7) by using an SC932A or SC105 between the datalogger's CS I/O port and the RF422's RS-232 port.

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