The Town of Ponoka is in the initial deployment of the Neptune R900 radio frequency water meter interface units. In an effort to help further the understanding of radio frequencies the goal of this letter is to provide some facts regarding the operation of the R900 system.
It should be noted that nearly 120 million radio frequency (RF) devices have been installed in the past 5 years in North America to gather usage data from water, gas and electric meters. Utilities of all sizes and types have realized the operational and customer service benefits of automating their data collection processes.
What are Radio Frequencies?
Radio frequencies are part of a broad range of energy phenomena called the electromagnetic spectrum. Everything in the electromagnetic spectrum consists of waves of energy that are measured in terms of their frequency and magnitude. The electromagnetic spectrum is often subdivided into two categories: ionizing radiation and non-ionizing radiation.
Radiation that has enough energy to move atoms in a molecule around or cause them to vibrate, but not enough to remove electrons, is referred to as non-ionizing radiation. Examples of this kind of radiation are sound waves, visible light, and microwaves.
Radiation that falls within the ionizing radiation range has enough energy to remove tightly bound electrons from atoms, thus creating ions. This is the type of radiation that people usually think of as “radiation”. Properties of ionizing radiation are used to generate electric power, to kill cancer cells, and in many manufacturing processes.
What kind of radio frequencies are used in meter reading?
Automatic Meter Reading (AMR) and Advanced Metering Infrastructure (AMI) systems typically operate in the 450MHz to 2.4GHz frequency range. RF systems that are used for AMR and AMI systems fall into the category of non-ionizing radiation, as they do not have sufficient energy to change the structure of molecules with which they come in contact.
The Neptune R900 device is a one-way battery operated device that operates in the 902-928 MHz band. That range of frequencies is referred to as an unlicensed band. The R900 uses frequency hopping spread spectrum to avoid harmful interference or collisions with radio waves emanating from other types of equipment. The Neptune R900 AMR system transmits every 14 seconds, with each transmission lasting only a fraction of a second. This equates to an R900 RF device transmitting for a total of less than 45 seconds per day.
All manufacturers, including Neptune, must follow government regulations when producing an RF transmitter. Neptune’s R900 RF transmitter is certified under Part 15.247 of the FCC regulations and has Industry Canada certification. This certification is required by law of any RF device.
The FCC regulations also provide limits to RF exposure and as such the R900 RF transmitter complies with the FCC RF radiation requirements for uncontrolled environments. FCC regulation states that in order to maintain compliance with these requirements, the antenna and any radiating elements should be installed to ensure that a minimum separation distance of 20cm is maintained from the general population.
Additionally, the R900 RF transmitter’s field strength is approximately 10 times less than what Health Canada has set out as the maximum allowable field strength of an RF device transmitting in the 3 kHz to 300 GHz range.
Neptune’s products are manufactured to meet established government regulations with the necessary certifications and approvals. There are over 4 million R900 radio frequency transmitters installed throughout North America with no reported issues of interference or health issues related to the transmission of the R900 RF device. We trust that this letter helps in providing a more clear understanding of radio frequencies as well as how the R900 operates.
Raymond Cheung, B.A.Sc.
NEPTUNE TECHNOLOGY GROUP