This product is no longer available and has been replaced by: CS506-L.
CS505-L Fuel Moisture Sensor
Services Available
Repair No
Calibration No
Free Support No


The CS505 Fuel Moisture Sensor was retired on September 22, 2009. It consists of an epoxy-encapsulated electronics package. It uses Time Domain Reflectometry Technology to measure the moisture content of the 10824 10-hour Fuel Moisture Stick. The 10824 is a USFS-specified, 10-hour, ponderosa-pine dowel that is purchased as a Common Accessory (see Ordering Info).



Operating Range 0 to 70% moisture content
Power Supply 9 to 18 Vdc
  • ±1% rms @ 0 to 10% moisture content
  • ±2.4% rms @ 30 to 40% moisture content
Current Use
  • 70 mA (active)
  • 10 µA (quiescent)
Output Signal ±2.5 Vdc square wave (with an output frequency of 600 to 1500 Hz)


Note: The following shows notable compatibility information. It is not a comprehensive list of all compatible or incompatible products.

Data Loggers

Product Compatible Note
21X (retired)
CR10 (retired)
CR1000 (retired)
CR10X (retired)
CR200X (retired)
CR206X (retired)
CR211X (retired)
CR216X (retired)
CR23X (retired)
CR295X (retired)
CR3000 (retired)
CR500 (retired)
CR5000 (retired)
CR510 (retired)
CR800 (retired)
CR850 (retired)
CR9000 (retired)
CR9000X (retired)

Additional Compatibility Information

Fuel Temperature

The CS506 is typically measured alongside the CS205/107, which measures the fuel temperature.


The 10974 Mounting Stake is often used to mount the CS505/10824 with the CS205/107. This stake places the probes twelve inches above the forest floor. Because the probes are mounted parallel to each other, shadowing is minimized. Cable ties are included for securing the cables to the side of the stake.

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