Detailed Radio Frequency - CoServ.com

CoServ Electric’s RF Mesh
Advanced Metering Infrastructure
RF/EMF Investigation
Date Analysis Performed: 05/03/2012

Introduction
CoServ Electric is a not-for-profit electric distribution cooperative and, as such, is regulated and directed
by its Board of Directors (elected representatives who oversee the operations of the cooperative). These
Directors hold a fiduciary responsibility to represent the interests of the Member - our consumers.
Surveys show that these Member consumers (made up of residents and business owners across Collin,
Denton, Tarrant, Grayson, Wise, and Cooke counties) are “tech savvy,” and look to CoServ to provide
them with resources to save energy and money. In order to meet our Members’ expectations, our
company must innovate and empower our Members with advanced technology to manage energy use.
After significant research and an extensive application process, CoServ Electric’s Board approved a $17.2
million Department of Energy Smart Grid Investment Grant in March 2010 to support the installation of
the AMI project – an electric distribution technology initiative called the CoServ eCoGrid. In September
2010, CoServ announced its selection of Landis+Gyr’s Gridstream RF technology to provide the advanced
metering and distribution technology supporting the initiative. The system consists of a robust two-way
communications network (a wireless system supported by collectors and routers), advanced metering,
distribution automation and personal energy management applications. Once fully deployed, the system
will provide operational efficiencies that will reduce costs, streamline operations, improve system
reliability, and offer Members new technology to monitor and reduce energy usage in their homes and
businesses.
CoServ has begun work on full system deployment, with project completion scheduled for April 2013. In
that timeframe, all CoServ Members will have an advanced meter installed on, or at, their premise.
Radio Frequencies
Radio Frequency (RF) is produced by all transmitting devices which are common and in widespread use
today. Examples of RF producers include radio broadcast stations, television stations, satellites
transmitting services to earth, and even our sun. A normal consequence of RF is the production of an
electromagnetic field or EMF.
There are three factors for consideration of human exposure to RF 1 :
1. Signal Strength
2. Distance from the transmitting device
3. How often the device transmits
1 An Investigation of Radiofrequency Fields Associated with the Itron Smart Meter, EPRI Technical Report 1021126, December
2010, www.epri.com page 3.

Establishment of Safe Exposure Levels
The Federal Communications Commission (FCC) provides the regulatory standards associated with
exposure to RF/EMF. IEEE standard C95.1-1191 (ANSI/IEEE C95.1-1992) specifies safe levels of human
exposure to radio frequency electromagnetic fields. The FCC has adopted the IEEE standard as the
foundation for regulations related to human exposure limits and has been presented as a regulation in
47CFR1.1310. The source document for human EMF exposure limits is now known as Office of
Engineering & Technology (OET) Bulletin 65. There have been no changes to the exposure limits.
OET Bulletin 65 refers to two safety limits which are Occupational/controlled limits and General
population/uncontrolled limits. General population/uncontrolled limits will apply to situations which
the general public may be exposed, but not fully aware of, their potential exposure or cannot exercise
any control over their exposure. An example of this is a radio transmission tower which is exposing
people to EMFs. This definition is the basis for comparisons of regulatory exposure limits to actual field
readings taken by CoServ personnel. This is the category CoServ’s AMI RF Mesh network, including the
AMI meter, falls under.
OET Bulletin 65 defines the limits for Maximum Permissible Exposure as values of electric and magnetic
field strength and power density for transmitters. For equipment that operates intermittently or in a
“burst” mode – such as the AMI meter- OET Bulletin 65 defines the period over which exposure can be
averaged and will represent a similar level of exposure as a maximum continuous exposure. This data
produces a minimum safe distance to the source.
The devices on a Member’s residence or business that uses the RF Mesh network are the radio module
inside of the meter and the devices used for a Home Area Network (HAN). Table 1 2 below provides the
equivalent minimum safe distance in an uncontrolled environment for the mentioned RF sources.
RF Mesh Device
Residential and C&I modules
Home Area Network Radio
Home Area Network Device
Table 1
Equivalent MSD – Uncontrolled Environment
0.63 inches
0.05 inches
0.05 inches
As a worse case, this table indicates a person will need to remain 0.63 inches from the radio device in an
AMI meter for an exposure limit to be greater than allowed. The distance between the radio and the
glass covering the meter is greater than this; so a hazardous exposure is not possible if the normal mode
and construction of the system and meter remain intact.
Another measurement to be considered with a RF/EMF investigation is the power density of the
transmitting device. For this investigation, the RF Mesh devices remain the same. Table 2 3 provides
information related to power density in milliwatts per square centimeter (mW/cm 2 ).
2 Landis + Gyr, “Acceptable Exposure Limits to Gridstream RF Devices”, page 6.
3 Ibid.

RF Mesh Device
Max FCC
Permissible
Exposure
F[MHz]/1500
Exposure @ 1
foot from
source
(Continuous
Transmission)
Percent of
FCC
Exposure
Limit
Exposure at 1
meter (3.28
feet) from
source
Continuous
Transmission)
Percent of
FCC
Exposure
Limit
Residential and C&I Endpoints 0.6 0.3707 61.78% 0.03 5.6%
HAN – Endpoint HAN Radio 1.6 0.2852 17.83% 0.03 1.6%
Table 2
Review of this information shows that, under normal exposure conditions, the exposure level for the RF
Mesh equipment, including the meter, will be below FCC requirements.

Field Analysis
Date Analysis Performed: 05/03/2012
Readings Performed by: Kevin Maynard – Communications Foreman, CoServ Electric
Device Used: NARDA SRM-3006
Serial Number: H-0024
Calibration Date: 03/27/2012
The device used to test EMF is a NARDA SRM-3006 Selective Radiation Meter. It is used to measure RF
and EMF levels and is equipped with a spectrum analyzer. The device allows for the determination of
EMF and RF strength levels by providing ambient and specific frequencies down to individual
components for detailed analysis. The device allows for ability to calculate the maximum permissible
exposure for a given frequency. It is equipped with a three –axis (iso-tropic) E-field antenna which is a
non-directional electrical field measurement antenna.
The SRM-3006 captures the signal(s) from the AMI meter and will display in real time the actual pulse of
the transmitter and the maximum peak of the transmit packet from the AMI meter. The SRM-3006
samples RF signals in the 902-928 MHz spectrum for approximately 5000 to 6000 cycles with a sweep
time of 39 milliseconds at each distance. This cycle duration is adequate to capture transmissions from
the AMI meter as it communicates to the RF Mesh network. The SRM-3006 is programmed to show the
‘FCC General Public Access’ regulatory limit which is displayed as mW/cm 2 , mW/m 2 , and as a
percentage of the FCC limit. Additional programming of the SRM-3006 includes the limits of several
other standards and regulatory rules.
The frequencies used by the radio module and the HAN device were not investigated as separate
frequencies. Therefore, captured power densities will be accumulative of the devices and conclusions
will be based on a worst case scenario.
Actions
Using the SRM-3006, outdoor readings were taken at one (1) foot and three (3) feet distances from the
meter for 5 minutes at each distance. Readings were also taken inside of residence at approximately
two (2) feet directly behind the meter.
Once all of the readings had been completed inside of residence, another reading was taken inside the
residence to capture all ambient frequencies which existed in the residence.
Readings
Location: Outside, 1 foot from meter

Figure 1 - Power Density
Findings: Reading is at 274.6 mW/m 2 . Conversion to mW/cm 2 – divide by 10,000 = .02746 mW/cm 2 .
Figure 2 - FCC Exposure Percentage
Findings: Reading is 4.497% of FCC Exposure percentage.
Location: Outside, 3 foot from meter

Figure 3 - Power Density
Findings: Reading is at 1.065 µW/cm 2 . Conversion to mW/cm 2 – divide by 10 = 0.1065 mW/cm 2 .
Figure 4 - FCC Exposure Percentage
Findings: Reading is .202% of FCC Exposure percentage.
Location: Inside, 2 feet from meter

Figure 5 - Power Density
Findings: Reading is at 2.211 mW/m 2 . Conversion to mW/cm 2 – divide by 10,000 = .0002211 mW/cm 2 .
Figure 6 - FCC Exposure Percentage
Findings: Reading is .035% of FCC Exposure percentage.
Location: Inside – Ambient frequencies

Findings: No remarkable findings
Comments
Members may be able to find a relatively inexpensive meter that claims it provides EMF readings.
These meters are typically a wide band product which covers a frequency range of 1MHz to 8GHz and
are equipped with a simple omni-directional antenna. It should be noted, these devices are not
designed to be frequency specific or a true EMF measurement. These meters will measure fields from
all sources that transmit from 1MHz to 8GHz and typically do not measure using E-Field or H-Field. E-

Field is the electrical component and the H-Field is the magnetic component of an EMF field.
Conclusions
Comparison of FCC Guidelines to the manufacturer’s meter specification and the field investigation is
shown in the table below.
Location/Distance
FCC Permissible
Power Density
(mW/cm 2 )
Manufacturer
Spec Power
Density
(mW/cm 2 )
Calculated
Percentage
Power Density
Measured
(mW/cm 2 )
Calculated
Percentage to
FCC
Recorded
Percentage to
FCC
Outside/1 foot 0.6000 0.3707 61.7833% 0.2746 4.5800% 4.4970%
Outside/3 foot 0.6000 0.3707 61.7833% 0.1065 0.1775% 0.2020%
Inside/2 foot 0.6000 0.3707 61.7833% 0.0002211 0.0369% 0.0350%
The RF/EMF emissions from the installed AMI meter at this residence falls well under the requirements
of the FCC as defined in OET Bulletin 65. Additionally, the values recorded were under the specifications
provided by the vendor of the equipment.
An examination of the ambient frequencies in the residence show there are exposures which are
naturally occurring and greater in power density than what is contributed by the AMI meter.
For more information on AMI and the RF impacts, please refer to
EPRI Radio-Frequency Exposure Levels from Smart Meters: A Case Study of One Model
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