Radio Frequency Information

Similar to the city's existing meter reading system, the new transmitter radios (not the new meters) use radio frequencies (RF) to transmit data to the Fitchburg Utility. The RF exposures from this transmitter radio are much lower than many common household devices such as cell phones, wireless routers, and microwaves. One common misconception about these radios is that they are always "on" or transmitting, when in fact they are transmitting less than 1 second per day.

Comparison of Typical Radio Frequency (RF) Exposures

Device Relative Power Density in microwatts per square centimeter (µW/cm2)
FM radio or TV broadcast station signal 0.005
Fitchburg water meter radio at 10 feet
0.54*
Cyber cafe (Wi-Fi) 10-20
Laptop computer 10-20
Cell phone held up to head 30-10,000
Walkie-talkie at head
500-42,000
Microwave Oven (2' from door) 5,000
Source: Richard Tell Associates, Inc.
*Source: Sensus

Radio Frequency Output Information for the Water Meter Radios
  • The AMI system transmits on a primary use (unshared) licensed band in the 890-960 MHz spectrum.
  • The transmission time is extremely short, less than 0.12 milliseconds.
  • The transmitter transmits once every 4 to 5 hours. Total transmission time is less than 1 second per day.
  • When not transmitting data, the transmitter radio remains off.
  • The transmitter's power output is 0.63W (the average light bulb is 60W).
  • The transmitter's power density is 0.126 mW/cm2 at 20 cm. The FCC guideline for Maximum Permissible Exposure (MPE) is 0.610 mW/cm2 at 20 cm.
Resources
  • Public Health Madison and Dane County's Smart Meters Report
  • Radio Frequency and Safety Compliance
  • Links to Regulatory and Other Agency Reports on Radio Frequency
  • Electric Power Research Institute Smart Meter Study
  • Sensus