The Calsense Spread Spectrum Radio communication option, model CS3-SR, enables two or more controllers to communicate using spread spectrum radios. A spread spectrum radio is a 1-watt radio modem that uses the 902-928 MHz ISM band. 

  • Blanket your entire campus with wireless communication so your Calsense controllers can share a single central communication option
  • Does not require any trenching or wires
  • Does not require FCC licensing

Can be used as a communication path for FLOWSENSE® technology to share a single internet-connected central communication option, programming information, and flow

Spread Spectrum Radio Communications Details

This option also enables the Calsense Command Center Online web application to communicate with a controller through a spread spectrum radio system. A spread spectrum radio system consists of one or more spread spectrum radio hubs and one or more controllers in the field with the CS3-SR option. The hub manages data flow between the cloud and surrounding controllers.

Spread Spectrum Radio Communications Accessories


An antenna, purchased separately, is required to use the CS3-SR option for communication. Calsense offers three antennas, each designed to accommodate specific situations.

  • The Calsense Stubby Antenna, model SR-STUBBY, is a 3-dBi omnidirectional surface mount antenna designed for all environments and applications.
  • The Calsense Stick Antenna, model SR-STICK-X, is a fiberglass omnidirectional antenna used to extend the range of a spread spectrum radio and is often recommended for use with spread spectrum hubs and repeaters. This antenna is available in 0-, 3-, and 6-dBi, represented by X in the part number.
  • The Calsense Yagi Antenna, model SR-YAGI-X, is an aluminum directional antenna typically used to extend the communications range of a specific controller location. This antenna is 6- and 9-dBi, represented by X in the part number.

Note: LMR-400-DB or LMR-600-DB cable is required if mounting a stick or yagi antenna.

Optional Equipment

Calsense also offers other equipment, including a frequency filter, surge protection and external mounting options for spread spectrum radio antennas.

  • The Calsense Spread Spectrum Frequency Filter, model SR-FILTER, is a bandpass filter used to help prevent interference from unwanted frequencies by filtering them out.

Note: An SR-FILTER is recommended when using an SR-STICK or SR-YAGI antenna.

  • The Calsense Antenna Cable Surge Protector, model ANT-PROT, helps protect the RF filter, if installed, and the radio equipment from lightning strikes.

Note: An ANT-PROT is required when using an SR-STICK antenna and recommended when using an SR-YAGI.

  • The Calsense Antenna Standoff Mount, model ANT-SOM, is a three-foot standoff mount used for installing an antenna on a lattice tower, up to 3″ in diameter.
  • The Calsense Antenna Tripod, model ANT-TRIP5, is a non-penetrating five-foot high tripod mount which is ideally suited for roof mount applications. and can be bolted down or weighed down with standard cinder blocks.

Spread Spectrum Radio Communications Specifications

Wireless Interface

  • Frequency Range: 902 – 928 MHz
  • Output Power: up to 1-watt
  • Data Range: up to 2-miles, clear line of sight


  • Operating Temperature: -40° to 75°C (-40° to 167°F)
  • Relative Humidity: 0 to 95%, non-condensing


  • Emissions: FCC, IC
  • Safety: UL® Class 1, Div 2, EN 60079-0:2012 + A11:2013, EN 60079-15:2010


  • 3-year limited warranty

FLOWSENSE is a registered trademark of California Sensor Corporation dba Calsense.
UL is registered certification mark of UL LLC.