This product is no longer available and has been replaced by: RF401A. Some accessories, replacement parts, or services may still be available.
RF401 900 MHz Spread-Spectrum Radio


The RF401 has a 910 to 918 MHz operating frequency range, which is used in the US and Canada. This 100 mW spread-spectrum radio can transmit data to another RF401 radio, an RF430 radio, a CR206(X) datalogger, or an AVW206 vibrating-wire interface.

The RF401 supports point-to-point and point-to-multipoint communications. It can serve as a field modem/radio while connected to the datalogger or as a base station modem/radio while connected to a computer. The radio can also serve as a stand-alone RF router/repeater.

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Benefits and Features

  • Rugged, low-cost transceivers
  • Can be used in the field as a transceiver or in the office as the base station
  • Individual FCC license not required
  • Transmits up to one mile with omnidirectional antenna; up to 10 miles with higher gain directional antennas at ideal conditions
  • Settings stored in non-volatile memory
  • Frequency-hops over 25 channels avoids interference from other spread spectrum radios
  • Optional extended temperature testing
  • Faster communication due to elimination of some small "link state packets"
  • Ability to have stand-alone RF router/repeaters (up to 8 repeaters)
  • Greater immunity to interference and RF collisions by using RF retries
  • Reduced power consumption by the datalogger, as the radios perform "packet address filtering"
  • Designed for use in PakBus networks
  • Built-in setup menus allow access to advanced functionality

The RF401-series and RF430-series spread-spectrum radios are similar. The models in these two series differ in their ports used for connecting to computers/dataloggers, in their frequencies, and in their transmitting power. Refer to the following table for specifics.

RF401A RF430
RF411 (retired) RF411A RF431 (retired) RF416 RF432 (retired)
Frequency 910 to 918 MHz
US & Canada
920 to 928 MHz
Australia & New Zealand
2.450 to 2.482 GHz
USB Ports
CS I/O Ports
RS-232 Ports
Transmitting Power 100 mW 250 mW 100 mW 100 mW 250 mW 100 mW 50 mW 50 mW


Detailed Description

The RF401 reduces susceptibility to RF interference from other spread spectrum devices by providing user-selectable frequency hopping patterns. Spread spectrum radios spread the normally narrowband information signal over a relatively wide band of frequencies. This process allows communications to be more immune to noise and interference from RF sources such as pagers and cellular phones.


Operating Frequency 910 to 918 MHz
Type Frequency Hopping Spread Spectrum (FHSS) Transceiver
RS-232 Baud Rate 38.4K, 19.2K, 9600, 4800, or 1200 bps
Channel Capacity 65,000 Network Identifiers share 25 hop channels.
Frequency Hopping Patterns Six different selectable patterns
Frequency Control Direct FM
Receiver Sensitivity -110 dBm at 10-4 bit error rate (Campbell Scientific protocols will issue retries wherever a bit error occurs.)
Interference Rejection 70 dB at pager and cellular phone frequencies
Transmitter Power Output 100 mW (nominal)
Antenna Connector Reverse polarity SMA
Power 9 to 16 Vdc
LEDs Power on, TX, RX, diagnostics
RS-232 Connector 9-pin “D” female (4 wire: Tx, Rx, CTS, GND)
CS I/O Connector 9-pin “D” male

Newer dataloggers supply power to the RF401 radio on this connector. Dataloggers purchased before December 1997 require the pn 14291 Field Power Cable.
Power Connector Barrel plug, center positive 12 V (used to connect the 14291 Field Power Cable)
Standard Operating Temperature Range -25° to +50°C
Extended Operating Temperature Range -55° to +85°C

The push button that allows you to check/edit programmable settings while the radio is connected to a computer may not operate at temperatures colder than -25°C.
Dimensions 11.4 x 7.0 x 2.9 cm (4.9 x 2.8 x 1.2 in.)
Weight 227 g (8 oz)

Average Current Drain

Standby < 1 mA (power-saving options used)
Receiving 24 mA
Transmitting < 75 mA



Internal Radio of CR206(X) Dataloggers

The RF401 spread spectrum radio can communicate with the internal spread spectrum radio of our CR206(X) dataloggers. Certain RF401 settings must match the CR206(X) settings for communications between the radio and datalogger to be successful. The factory default settings of these devices may not match; therefore, they may need to be reconfigured before communications can take place. For more information, refer to the Quick Reference Guide for Setting Up RF401-to-CR206 Communication application note

Other Spread Spectrum Radios

The RF401 can be used in networks containing RF430 and RF400 radios. When RF401 radios are used in networks containing RF400 radios, the Protocol must be set to Transparent. Also, if RF400 and RF401 radios will be in the same RF proximity, do not use 28, 44, 52, 56, or 60 for the RF400 Net Address. RF400 radios with Net Addresses of 28, 44, 52, and 56 interfere with RF401 radios with Net Addresses of 0, 1, 2, and 3, respectively. The RF400 Net Address of 60 interferes with all RF401 Net Addresses.

Campbell Scientific does not recommend using the RF401 in networks containing FGR-115 or RF450 radios.

Transparent and PakBus Protocols

Do not mix RF401 radios set to the Transparent protocol with RF401 or RF430 radios set to either of the PakBus protocols, since this will produce RF traffic without any RF communications. However radios with the PakBus Aware and PakBus Node settings can coexist in the same network (i.e., some radios set to PakBus Aware and some radios set to PakBus Node).

Datalogger Considerations

Compatible Contemporary Dataloggers

CR200(X) Series CR800/CR850 CR1000 CR3000 CR6 CR9000X

Compatible Retired Dataloggers

CR500 CR510 CR10 CR10X 21X CR23X CR9000 CR5000 CR7X

*Although the CR9000 and CR9000X are compatible, the RF401 radios do not support their fastest communication rates, and are therefore not practical for many CR9000(X) applications.

Enclosure Considerations

A desiccated, non-condensing environment is required. The 14162 Mounting Kit includes hardware for securing the RF401 to an enclosure backplate (see Ordering Info).

Compatible Enclosures

ENC10/12 ENC10/12R ENC12/14 ENC14/16 ENC16/18


RF401 Series OS v.04 (646 KB) 08-14-2008

Current RF401, RF411, RF416 firmware. Requires the Device Configuration Utility.

View Update History

Frequently Asked Questions

Number of FAQs related to RF401: 12

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  1. For the RF401, there is not a Status table similar to that for a datalogger, but some statistical information can be retrieved via terminal mode.

  2. No. The RF401 only transmits at the 100 mW level. If additional power is needed, a directional antenna or a high-gain omnidirectional antenna can be used to increase the effective output of the system.

  3. Campbell Scientific continues to provide the RF400 to RF401 upgrade as a service. There is a minor upgrade (pn 18206) and a major upgrade (pn 18207). As the RF401 is now retired, however, it may be a better investment to forego the upgrade and purchase a new, higher output, 250 mW RF401A radio instead. No upgrade service is available to convert an RF400 or RF401 to an RF401A. 

  4. The functions of the RF401-series and RF400-series are essentially the same when using the transparent protocol with mixed-array datalogger operating systems. The biggest change is the addition of two new protocol options in the RF401: PB Aware and PB Node. These new protocol options make the radio easier to use in a PakBus network.

  5. No. For high-frequency data applications, Campbell Scientific recommends using the RF450.

  6. To achieve the same characteristics and performance of an original RF401, order the major RF400 to RF401 upgrade service (pn 18207). 

  7. No. They do not use the same over-the-air communications protocol. In fact, unless extra steps are taken, the two models will cause interference with each other.

  8. Yes. The LoggerNet software provides RTMC, an HMI software. The CR10X can be provided with a Modbus communications protocol or PakBus. Both will work very well and are commonly used in SCADA systems. With the Modbus protocol, the CR10X can interface with existing software, and/or existing PLCs.

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