MramfqHflpQgflCTnH"|g

/ W \

\

J&&

*"*CAU 0* *

in a* NBS TECHNICAL NOTE 1014

U.S. DEPARTMENT OF COMMERCE / National Bureau of Standards

Electromagnetic Interference (EMIj

Radiative Measurements for

Automotive Applications
NATIONAL BUREAU OF STANDARDS

The National Bureau of Standards' was established by an act of Congress March 3, 1901. The

Bureau's overall goal is to strengthen and advance the Nation's science and technology and

facilitate their effective application for public benefit. To this end, the Bureau conducts

research and provides: (1) a basis for the Nation's physical measurement system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau's technical work is performed by the National Measurement Laboratory, the National Engineering Laboratory,

and the Institute for Computer Sciences and Technology.

THE NATIONAL MEASUREMENT LABORATORY provides the national system of

physical and chemical and materials measurement; coordinates the system with measurement

systems of other nations and furnishes essential services leading to accurate and uniform

physical and chemical measurement throughout the Nation's scientific community, industry,

and commerce; conducts materials research leading to improved methods of measurement,

standards, and data on the properties of materials needed by industry, commerce, educational

institutions, and Government; provides advisory and research services to other Government

Agencies; develops, produces, and distributes Standard Reference Materials; and provides

calibration services. The Laboratory consists of the following centers:

Absolute Physical Quantities2 — Radiation Research — Thermodynamics and

Molecular Science — Analytical Chemistry — Materials Science. THE NATIONAL ENGINEERING LABORATORY provides technology and technical

services to users in the public and private sectors to address national needs and to solve national problems in the public interest; conducts research in engineering and applied science

in support of objectives in these efforts; builds and maintains competence in the necessary

disciplines required to carry out this research and technical service; develops engineering data and measurement capabilities; provides engineering measurement traceability services; develops test methods and proposes engineering standards and code changes; develops and

proposes new engineering practices; and develops and improves mechanisms to transfer

results of its research to the utlimate user. The Laboratory consists of the following centers:

Applied Mathematics — Electronics and Electrical Engineering2 — Mechanical

Engineering and Process Technology2 — Building Technology — Fire Research —

Consumer Product Technology — Field Methods.

THE INSTITUTE FOR COMPUTER SCIENCES AND TECHNOLOGY conducts

research and provides scientific and technical services to aid Federal Agencies in the selection, acquisition, application, and use of computer technology to improve effectiveness and

economy in Government operations in accordance with Public Law 89-306 (40 U.S.C. 759), relevant Executive Orders, and other directives; carries out this mission by managing the Federal Information Processing Standards Program, developing Federal ADP standards

guidelines, and managing Federal participation in ADP voluntary standardization activities; provides scientific and technological advisory services and assistance to Federal Agencies; and

provides the technical foundation for computer-related policies of the Federal Government.

The Institute consists of the following divisions:

Systems and Software — Computer Systems Engineering — Information Technology.

'Headquarters and Laboratories at Gaithersburg, Maryland, unless otherwise noted; mailing address Washington, D.C. 20234.

2 Some divisions within the center are located at Boulder, Colorado, 80303.

The National Bureau of Standards was reorganized, effective April 9, 1978.
Electromagnetic Interference (EMIJ

gtgVftO of S&S&B*

AUG 17 1979

fsCC

Radiative Measurements for u

^

Automotive Applications* ^

i

J. W. Adams

H. E. Taggart

M. Kanda

J. Shafer

Electromagnetic Technology Division

National Engineering Laboratory

National Bureau of Standards

Boulder, Colorado 80303

*This work was carried out at the National Bureau of Standards under the

sponsorship of the Department of Transportation, National Highway Traffic

Safety Administration.

U.S. DEPARTMENT OF COMMERCE, Juanita M. Kreps, Secretary

Sidney Harman, Under Secretary

Jordan J. Baruch, Assistant Secretary for Science and Technology

NATIONAL BUREAU OF STANDARDS, Ernest Ambler, Director

Issued June 1979
NATIONAL BUREAU OF STANDARDS TECHNICAL NOTE 1014

Nat. Bur. Stand. (U.S.), Tech. Note 1014, 48 pages (June 1979)

CODEN: NBTNAE

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1979

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402

Stock No. 003-003-02086-9 Price $1.80 (Add 25 percent additional for other than U.S. mailing)
Table of Contents

Page

1.0 Introduction 1

2.0 Measurement Factors 1 2.1 Field Strength Levels Around Passenger Cars 2 2.2 Field Strength Levels Around a Tractor-Trailer 2 2.3 Factors that Influence Field Strength Levels 2 2.4 Effects of Multiple Electromagnetic Sources 3 2.5 Uncertainties in the Reported Field Strength Levels 4 2.5.1 Electric Field Probes 4 2.5.2 Magnetic Field Probes 5

3.0 Presentation of Measured Data 5 3.1 Magnetic Field Measurements 5 3.2 Summary of Measurement Results 6

4.0 Susceptibility Measurement Factors 7 4.1 Protective Measurement Suggestions 7 4.2 Susceptibil ity Evaluation 7 4.3 Electromagnetic Radiation Hazard to People 8

5.0 Test Limits for Field Strength Levels 9

6.0 Summary and Conclusions 10

7 .0 Acknowl edgments 10

8 .0 References 10

ill

iMJmmmmimiMKmimiaai
List of Figures

Page

Fig. 1. Photo of NBS probe being used to make near-field electrical field

strength measurements 16

Fig. 2. Electric field strength levels (V/m) at various locations around a full -si zed passenger vehicle on dry ground with an onboard

110 watt transmitter, 40.27 MHz, with a base-loaded antenna

located at the center of the roof top 17

Fig. 3. Electric field strength levels (V/m) at various locations around a compact vehicle on dry ground with an onboard 100 watt transmitter, 27.610 MHz, with a base-loaded antenna located at the center of the roof top 18

Fig. 4. Electric field strength levels (V/m) at various locations around a compact vehicle on a metal ground plane with an onboard 100 watt transmitter, 27.610 MHz, with a base-loaded antenna located at the center of the roof top 19

Fig. 5. Electric field strength levels (V/m) at various locations around a tractor-trailer vehicle on dry ground with an onboard 100 watt transmitter, 27.610 MHz, with a base-loaded antenna located at the

center of the roof top 20

Fig. 6. Electric field strength levels (V/m) at various near-field

locations, 110 watt transmitter, 40.27 MHz, base-loaded antenna

located at the center of the roof top of the passenger vehicle, on dry ground 21

E, full-sized car, metal ground 22

E, full-sized car, dry ground 22

E, car beside transmitting car 23

E, full -si zed car near metal wall 23

E, compact car, dry ground 24

E, compact car, metal ground 24

E, tractor-trailer, dry ground 25

E, tractor-trailer, metal ground 25

E, tractor-trailer, beside transmitting car, dry ground 26

E, tractor-trailer beside transmitting tractor-trailer,

dry ground 26

H, full-sized car, metal ground 27

H, full-sized car, dry ground 27

H, compact car, metal ground 28

Fig. 7.

Fig. 3.

Fig. 9.

Fig. 10

Fig. 11

Fig. 12

Fig. 13

Fig. 14

Fig. 15

Fig. 16

Fig. 17

Fig. 18

Fig. 19

iv
List of Figures (Continued)

Page

Fig. 20. H, compact car, dry ground 28s

Fig. 21. H, tractor-trailer, metal ground 29

Fig. 22. H, tractor trailer, dry ground . 29

Fig. 23. E, fixed AM transmitters, different powers, distances, and frequencies 30

Fig. 24. E, fixed AM transmitters, different powers, distances, and frequencies 30

Fig. 25. E, fixed AM transmitters, different powers, distances, and frequencies 31

Fig. 26. E, fixed AM transmitters, different powers, distances, and frequencies 31

Fig. 27. E, fixed FM and TV transmitters, different powers, distances, and frequencies 32

Fig. 28. E, fixed FM and TV transmitters, different powers, distances, and frequencies 32

Fig. 29. E, fixed FM and TV transmitters, different powers, distances, and frequencies 33

Fig. 30. E, worst case, 100 percent 33

Fig. 31. E, worst case, normalized, 100 percent 34

Fig. 32. E, worst case, 95 percent 34

Fig. 33. E, worst case, normalized, 95 percent 35

Fig. 34. E, worst case, 90 percent 35

Fig. 35. E, worst case, normalized, 90 percent 36

Fig. 36. E, worst case, 75 percent 36

Fig. 37. E, worst case, normalized, 75 percent 37

Fig. 38. E, worst case, 50 percent 37

Fig. 39. E, worst case, normalized, 50 percent 38

Fig. 40. E and H, percentile-based test limits 39

Electromagnetic Interference (EMI) Radiative Measurements for Automotive Applications

J. W. Adams, H. E. Taggart, M. Kanda, and J. Shafer

This report describes the measured results of the electromagnetic (EM) environment

encountered by three different-sized vehicles exposed to a selection of CB and mobile radio

transmitters and broadcast stations. The vehicle in these situations is immersed in the near field of the radiating signals and the measured data is near-field data. This report gives

measured data of electric and magnetic fields measured independently. The purpose of the report is to identify the EM environmental conditions under different circumstances in order

to estimate EMC testing criteria for vehicles and their electronic systems.

Key words: Mobile-radio; near-field strength levels; vehicular electromaqnetic environment;

vehicular near-zone electric fields; vehicular near-zone magnetic fields;worst-case EM fields.

1.0 Introduction

As the automotive industry moves from mechanical and hydraulic control systems to electronic

control systems, the reliability of these electronic systems becomes paramount from a safety standpoint.

Although these electronic systems can provide economical fuel use and low pollution, they increase the need to plan for electromagnetic compatibility (EMC) with the environment in which they operate.

Shielding and filtering are well-known ways of achieving EMC, but they cost money. Reliable measurements are the key to knowing the electromagnetic environment and to determining when one has achieved sufficient compatibility with the environment at a minimum cost.

To help achieve a reliable data base, the National Bureau of Standards (NBS), with the support of

the National Highway Traffic Safety Administration, has made measurements of both electric and magnetic

field strength levels around different types of vehicles in a variety of situations. NBS has also developed methods to measure susceptibility of electronic components to these fields.

The electromagnetic environment in which a vehicle must operate is extremely variable as to range of frequency, range of magnitude, type of field, and direction of source. It is extremely difficult to make sufficient measurements to completely describe this diverse environment. Therefore, an attempt has been made to identify the worst (highest) field strength levels that exist and measure them. The

relative effect (energy content) of field increases as the square of field strength level, and this

coupled energy is what has the potential for disrupting or degrading electronic systems. Another factor

which was influential in determining which environments should have priority in measuring the levels in

a measurement program is the distance from the source. A relatively weak transmitter that is nearby

produces much stronger fields than a relatively powerful transmitter at a distance. For these reasons,

the field strength levels measured were mostly around vehicles with onboard transmitters or close to transmitters.

The data base provided should give some guidance to manufacturers as to what field strength levels their products may encounter, and thus establish susceptibility test bounds.

2.0 Measurement Factors

There are a number of factors that influence not only the levels of field strength around vehicles

but also the measurement strategy. Some of these factors are: size and shape of vehicle; number,

power, frequency, and proximity of sources; transmitter and antenna characteristics; ground

effects; and interactive effects. Changes in vehicle design such as increasing use of plastics,

fiberglass, and electronic systems will alter the type of data base needed.

The need to make vehicles more fuel efficient forces weight reductions. One way this is achieved

is through the increased use of fiberglass and plastics. This will impact the electromagnetic shielding

effectiveness of body structures, usually negatively.

Increased use of microelectronics increase both electromagnetic environmental data needs and design

requirements. These microelectronic systems are increasingly vulnerable to EMI as their power requirements decrease -- it takes approximately the same amount of energy to disrupt a system as it does

to operate it. Some microprocessors require milliwatts or less for operation.

—"""'"Hwrfli
2.1 Field Strength Levels Around Passenger Cars

Field strength levels were measured around both a full-sized and a compact passenger car under a number of conditions. Three frequencies in the land mobile bands were used: 40.27 MHz in the 30 to

50 MHz band, 162.475 MHz in the 150 to 170 MHz band, and 416.975 MHz in the 400 to 520 MHz band. Different types of antennas, different antenna locations, different types of ground planes, and different types of metallic structures adjacent to the vehicle were used. Fields were measured around a vehicle adjacent to another with an on-board transmitter. Measurements were also made in the high

frequency band, e.g., at nominal frequencies of 4, 7, 14, 21, and 27 MHz. These measurements were made

with a nominal 100 watts of transmit power. Figure 1 is a photograph showing how the measurements were made. Limited measurements were made around a vehicle parked near fixed, high-power transmitters such

as FAA radars, AM and FM radio stations, and VHF and UHF TV stations. Figures 2, 3, and 4 show samples

of these field strength levels for the case where the transmitter is located in the car.

Several important points were observed: field strength levels vary greatly with location around the vehicle; the location of hot spots varies greatly depending on many different parameters; fields

encountered when a vehicle is on a metallic ground plane are usually higher than for one on a nonmetallic ground plane, especially at locations under the vehicle; the field strength levels usually

decrease with increasing frequency, approximately as the inverse of the square root of the frequency;

the field strength levels tend to vary inversely with the size of the vehicle.

Although the objective of these measurements was to determine the highest levels that could be expected, one region was excluded; the region within one-half meter of the antenna. In this region,

the field strengths are extremely high, over an order of magnitude higher than the highest fields

elsewhere. If any of the electronic systems, cables, or personnel are located within this region, many

more serious problems should be expected, and/or more expensive protection measures will have to be used.

A specific warning is appropriate for personnel to stay away from an antenna that is located on a fender or bumper of a car. Antennas located in the center of the roof are generally inaccessible to people, and also have better electrical characteristics due to the presence of a better ground plane.

2.2 Field Strength Levels Around a Tractor-Trailer

Federal Motor Vehicle Safety Standard (FMVSS) 121 requires strict stopping and controlling

requirements for trucks. Many manufacturers have opted to comply with FMVSS-121 by employing electronic

antiskid brake systems. These electronic systems then require EMC with the environment in which they must operate.

NBS has measured fields around a tractor-trailer under a variety of conditions. These are illustrated in figures 5 and 6. Field strength levels were measured when on-board mobile transmitters

were used as well as for adjacent vehicles with transmitters. In contrast to a passenger car, a metal ground plane does not significantly change field strength levels over those conditions that would exist

on asphalt or concrete for a truck. Figure 6 shows the effects of a mobile transmitter adjacent to a tractor-trailer.

2.3 Factors that Influence Field Strength Levels

Major factors that influence field strength levels include radiated power, type of antenna,

location of antenna, standing wave ratio (VSWR), location around vehicle, frequency, electrical

characteristics of ground on which vehicle rests, nearby metallic objects or walls, resonant structures,

shape of vehicle, size of vehicle, and size of apertures.

Most of these factors apply simultaneously, making exact analysis difficult. The field strength is proportional to the square root of radiated power. Antenna location and type cause variations, but not

in a predictable manner. The highest field strengths around a vehicle are usually near sharp corners, near resonant structures such as wheels, and on the underside of a vehicle located on a metal ground

plane. Fields decrease generally with increasing frequency, approximately as the inverse of the square

root of frequency. A full-sized car on a metal ground plane usually has higher field strength levels than it does on dry asphalt. Other nearby metallic objects tend to increase field strength levels. Sharp corners give higher electric field strength levels than smooth surfaces or more rounded corners.

At higher frequencies, an aperture such as a window allows stronger fields inside the vehicle than it will at lower frequencies. Vehicle dimensions are such that the vehicle itself becomes a resonant
structure between 20 and 40 MHz, depending on the size of the vehicle. This may be a very troublesome

portion of the frequency spectrum.

Magnetic field strength levels are highest near corners of large apertures such as windshields.

A mismatched antenna causes a high standing wave ratio, resulting in less radiated power than for

matched conditions, and hence lower external field strength levels. However, the antenna, cables,

microphones, etc., then have higher field strength levels in their immediate vicinity than would exist

under matched conditions.

2.4 Effects of Multiple Electromagnetic Sources

The existence of multiple sources at different frequencies and different power levels is a common occurrence in highly populated areas. Two examples are, first, the multitude of CB radios in an area

and, second, broadcast towers with man> transmitting antennas colocated on the same tower.

How these multiple sources must b; treated depend on the answers to several questions:

1. Will a device respond to energy at more than one frequency? An example of a device that

responds to energy over a wide range of frequency is a neon bulb. An example of a device that responds

only to energy at one frequency (narrow band of frequencies) is a radio with ideal selectivity.

2. Is the energy from several sources related, i.e., are the signals coherent? An example of two related sources is a radio relay station which receives on one frequency and transmits the same signal

on another frequency. In this case, two transmitters are transmitting the same information on two different frequencies, one with a slight time delay from the other. An example of two unrelated signals

are those radiated from two different radio stations. Unless special efforts are made to phase-lock or otherwise relate two sources, each is controlled by its own crystal, tank circuit, and modulation. It

is physically "unaware" of the existence of any other transmitters.

3. What are the magnitudes of the different signals relative to each other? Different

transmitters may use different power levels, may have different gain antennas (the energy may be more concentrated in one direction), may be at different distances, and may be at different frequencies.

4. How are the receiving-device, energy transducers aligned? Electric and magnetic field

strengths are vector quantities, and hence have directional as well as magnitude qualities. An alignment that couples maximum energy from one source may couple no energy (or any amount from zero to maximum) from a different source.

The four factors brought out by these questions complicate analyses for multiple sources to an overwhelming degree if some simplifications are not possible. The following simplifications are often

justified:

1. Devices will respond to energy at more than one frequency. If not, only one source will cause

a response, and single-source analysis is appropriate.

2. Different sources are incoherent. It is technically possible to relate sources, but there are few cases where this is desirable; therefore, it is seldom done. Sixty hertz power systems are an important, low-frequency exception.

3. Nothing should be assumed about the relative magnitudes of different-frequency signals at some

point.

4. Worst-case alignment (or orientation) should be assumed. This gives maximum coupling of energy, and although seldom achieved, may be achieved at some time or other, unless all sources and receiving devices are immobile.

With these simplifying assumptions, a relatively direct mathematical analysis can be used. Power

(energy per unit time) is proportional to E x H where the E and H vectors are related by the intrinsic

impedance of the medium, 1 = E/H; in an idealized free-space, far-field condition,

n = i = 376.7 ohms. Therefore, power is proportional to |E f/n; for three unrelated signals,

Ei sin co^t, E2 sin cogt, and E3 sin a^t, each brings power proportional to E^/t; , E6/i, and £yn. That is, Pj = Pi + P2 + P3. The effective resultant Ey

lmu» iLMOTffarnntnirt^iiiTtTiiirinriiinriraTrrffii'flffwiiflttft
that would have brought an equivalent amount of power as the total of the three uncorrel ated signals

is:

/

r 2 r 2 r 2

Table 1 shows- how different relative magnitudes would combine:

Table 1

(V/m)

L 2 (V/m)L 3 (V/m)

h-m

(V/m)

El (dB) above 1 V/m

E T

= 20 lo9iO

(E T/l^

.8

.5

.5.3

.3

.1

1 .8.5

.1.3

.1.1

1.732 +4.771

1.510 +3.579

1.225 +1.761

1.122 +1.004

1.086 +0.719

1.049 +0.414

1.010 +0.086

1.000 0.000

Unless two signals are of approximately equal amplitude, the magnitude of the combined signals is less than 2 dB greater than for a single signal. If there is a factor of two (or more) difference, the magnitude of the combined signals shrinks to less than 1 dB greater than for a single signal.

If there should be 10 equal signals of unity amplitude, E-p would equal 3.162, which is 10 dB higher than any for a single signal. Fortunately, this seldom occurs, as it is difficult to colocate 10 transmitters to achieve 10 equally strong signals. At a long distance this can be done, but then all the signals are weak, and singly or collectively cannot cause much effect.

The measurement of multiple signals is complicated by these same factors, but the same simplifying

assumptions cannot be made. The degree of coupling at particular orientations has a large effect on the uncertainties that must be attached to measured data.

2.5 Uncertainties in the Reported Field Strength Levels

Electric and magnetic fields around vehicles

because the vehicle is an antenna itself and pert

related in unknown ways and must be measured sepa perturbed conditions, no prior knowledge is avail devices have to respond to each parameter (E or H in unknown ways, and should measure the magnitude

the vector — the probe should have an isotropic

the field. Variations in frequency, temperature,

in may affect the probe uncertainty. The followi

of these conditions.

are not related as they are in the far field

urbs fields from any source, near or far. E rately. E and H are vector quantities, and u able as to their direction or magnitude. The

) independently, must not themselves perturb

of the vector quantity, regardless of the di response. The person handling the probe may

and the field strength levels the probes are

ng discussion gives a total uncertainty as a

This is and H are nder these

measuring

the fields

recti on of perturb

immersed

function

2.5.1 Electric Field Probes

The probe used for electric field measurements was designed to minimize the uncertainties one encounters when making near-field measurements [1]. The probe has an isotropic response, and the lead wires do not significantly perturb the fields being measured.

The uncertainty in the field strength levels reported are determined as follows:

1. The probe was calibrated to an uncertainty of +_ 1 dB [2].

4
2. The probe response is not perfectly isotropic, with variations of + 0.5 dB under normal use. Sometimes it was necessary for the person doing the measurement to be between the source and the probe.

The resulting field perturbation was estimated to cause an uncertainty no greater than + 3 dB. In any case, the basic probe uncertainty is unchanged.

3. A temperature instability causes a total probe/instrumentation total zero drift uncertainty of + 0.40 volts per meter for field strength levels above 10 volts per meter. At field strength levels below 10 volts per meter, the probe has an increasing uncertainty, increasing to + 3.5 dB at one volt

per meter.

4. At frequencies below 10 MHz, a frequency-dependent bias correction has been added. The correction is zero dB at 10 MHz, -3 dB at 3 MHz, and zero dB again at 850 kHz.

For field strength levels above 10 volts per meter for single vehicle measurements, the total uncertainty is _+ 1.5 dB over the entire frequency range over which they were used. If there are two vehicles involved, this uncertainty should be increased to + 4.5 dB for the values shown between the vehicles.

2.5.2 Magnetic Field Probes

The probes used to measure the magnetic fields were also developed at the National Bureau of Standards [3]. The probes do not have an isotropic response as the electric field probes do, since only

a single loop is used. Otherwise, they are constructed in a similar manner as the electric field probes

and have nonperturbing lead wires. Because the magnetic probes must be oriented for maximum field

strength, their overall measurement uncertainty is greater than the measurement uncertainty of the

electric field probes. The magnetic probes consist basically of a loop with a detector built into the center of the loop and nonperturbing, high-resistance line connecting the loop to the meter. Three

different probes were used to make the measurements in three frequency bands from 7 to 160 MHz.

The overall measurement uncertainty using the magnetic field probe is estimated to be + 5 dB.

3.0 Presentation of Measured Data

Figures 2 through 6 are illustrative of hundreds of pages of data that could be presented of measurement results under many different conditions. A worst-case, specific set of conditions was selected at each frequency. Usually this was when a vehicle was on a metal ground screen with an onboard transmitter. For each set of data for such a specific set of conditions there are a wide range

of values of field strength around the vehicle.

A first attempt at compiling all these data involved use of statistical descriptors such as the average, standard deviation, and upper tolerance limit. However, the way the values were measured

introduced serious (and deliberate) bias toward selection of the higher values during measurements.

This also made some of the measured distributions not normal, even though the total population of values

is probably normally distributed.

The use of a real-time probe allowed us to locate and measure the "hottest" spots, those where

field strength levels were highest. This gave a more accurate measure of the high levels than could be obtained with true random sampling and statistical prediction of upper tolerance limits.

Figure 7 is illustrative of the method finally selected for presenting a condensed form of the measured data. All of the measured values were ordered and ranked according to percentiles for a particular set of conditions and at one frequency. Box and whisker graphs of percentiles were used. The percentile key is given in the upper right region of each figure. Several frequencies were used for similar conditions. Six percentiles were used: 100 for the highest value measured, and 95, 90, 75, 50,

and 25 values. Sometimes 90 and 95 were the same, since no interpolation was used and thus there is only one bar inside the box. The box was used to indicate the range of values for the highest

proportion of data. It also indicates the most carefully measured values. Although values were measured at many random spots, the probe sensitivity limited the lower levels that could be measured.

In some cases, particularly at low frequencies, there were few or no regions that had low field strength

levels. At the higher frequencies, there were a wide range of values and many "cold" spots. Therefore,

the lower percentiles have been included to provide this information, even though there is an unknown

uncertainty in those values.

Figures 8 through 16 summarize measured data for several specific conditions and size of vehicle.

5

mimwaiwwmx
Two other factors, power and distance from source, have to be considered in calculating worst-case

values that may occur anywhere. The values in the HF frequency range (3-30 MHz) should be increased by

a factor of two, since higher power levels than NBS used are both legal and available. In the case of AM broadcast stations, a distance correction is needed, since service vehicles may be driven within

3 meters of some AM broadcast stations. Since near-field conditions exist, the field strength may not vary linearly with distance (1/d), but may vary as (l/d) x where x may be as high as 3. This means that for these very close distances, measurements are more accurate than predictions from calculations.

3.1 Magnetic Field Measurements

The magnetic field strength levels (H) measured in the near field are summarized in figures 17 through 22.

The maximum levels of H do not occur at the same spatial locations as the maximum E-field levels.

The maximum H-field levels tend to occur near edges of large apertures, e.g., corners of front and rear windshields. The larger the aperture, the higher the level of H. At higher frequencies, the smaller

(side) windows become resonant and have higher field strength levels. The H-field strength variations

with frequency show a pattern similar to E-field strength variations, i.e., decreasing levels with

increasing frequency, resonances excepted. The H-field values were not measured above 162 MHz, so comparisons cannot be made at 417 MHz.

The H-field strength levels are comparable to E-field strength levels on an energy density basis of comparison. (A free-space, far-field H-to-E conversion is used for simplicity.) If anything, the H-field levels are slightly lower than the E-field levels.

Inside a vehicle H-field strength levels are significantly lower than comparable E-field strength

levels.

3.2 Summary of Measurement Results

All measurement results are summarized in table 2. Table 2 lists the type of vehicle, type of ground surface, frequency, type of field, number of measurements, and five percentile values: 100, 95,

90, 75, and 50, and a comment column. The 25 percentile values were shown on the figures merely to indicate the ranges of levels measured. However, due to the poor probe sensitivity at the lower field

strength levels and due to the emphasis on measuring worst-case levels, the 25 percentile values are not used on the summary curves. The units of measure for the electric fields are volts per meter; the units of measure for the magnetic fields are amperes per meter, with the far-field volts-per-meter

equivalent in parenthesis. It is recognized that converting amperes per meter to volts per meter is not valid under near-field conditions, but this permits the reader to easily compare the magnitudes of the magnetic field results with the electric field results on an energy density basis. The magnetic field

strength levels reported were measured with a magnetic field probe — they were not obtained by

converting from E-field results.

Several methods of treating the measured data for each vehicle- frequency-antenna situation were tried. Levels inside a vehicle, levels under a vehicle, and other groupings of data from various

spatial regions around the vehicle were tried. No one grouping seemed to give consistently lower or higher results; therefore, the total number of measurements for a given condition was used to describe

the levels around the vehicle.

For instance, the average of levels measured under a vehicle was usually lower than the average of the total if the vehicle was on a nonmetallic surface; if the vehicle was on a metallic surface, this same group of levels measured under the vehicle was higher than the total. Similarly, other regions

varied due to other effects.

The measurement results listed in table 2 have been consolidated further to show the results for given sets of conditions.

Results of E-field measurements for a full-sized car, a compact car, and a tractor-trailer are summarized in figures 7 through 16. Similar results of H-field measurements are summarized in figures 17 through 22. Results of E-field measurements around vehicles in the vicinity of commercial

broadcast stations are summarized in figures 23 through 29; "D" on the figures is the distance from the vehicle to the base of the antenna in meters.

The worst-case (highest) levels for each of the three types of vehicles is summarized by percentile

in figures 30, 32, 34, 36, and 38. These curves are then "normalized" by increasing the actual field

6
strength levels measured with 100 watt sources to those levels representative of a higher legal power

level radiating source. This normalization is only in the HF frequency band, 3 to 30 MHz. At other

frequencies, the maximum legal power levels were used for the measurements. These normalized results

are shown in figures 31, 33, 35, 37, and 39.

Suggested levels for testing automotive electronics are given in figure 40. These are based on figues 31, 33, 35, 37, and 39. There are a few resonant conditions that exceed the values suggested in figure 40. The resonances measured generally occurred between 20 MHz and 50 MHz; this frequency range

will undoubtedly be a troublesome portion of the spectrum since vehicle dimensions are such that the vehicle itself becomes resonant.

From our observations, we conclude that there are three phenomena present, each supported by a thread of technical logic.

1. Each curve shows a resonant peak in the 20 to 40 MHz frequency range. Vehicle dimensions

(approximately 5 meters) are such that a half-wavelength resonance can be expected. There may be other

resonances at higher frequencies that were not observed due to the wide frequency separation in the higher test frequencies (above 40 MHz).

2. The field strength levels decrease inversely with the square root of frequency except for the resonant peaks. This follows a skin-effect loss. The metallic vehicle body structure has losses that

increase proportionally to the square root of frequency. The more energy that is dissipated in skin-effect losses, the less is available for nondissipative electromagnetic fields.

3. The larger the vehicle, the lower the field strength levels in and around it, for equal levels

of excitation power. The vehicle is an antenna, but the larger the volume for constant excitation

power, the lower the energy density (and hence field strength levels) for this larger volume.

4.0 Susceptibility Measurement Factors

Once a data base is established that tells what field strength levels can be expected (under worst-case conditions), designing and building equipment that is compatible with this environment

depends on test methods that indicate to what degree this compatibility has been achieved -- or predict

what will happen in this diverse environment.

4.1 Protective Measurement Suggestions

A designer must select the levels to which he wishes to "harden" his electrical components or

systems. In this context, harden means to shield and filter systems so as to provide immunity to electromagnetic fields. If he wishes a minimum of reliability that will get his product through a certain proportion of the time, he may choose to harden his system to withstand field strength levels indicated by the 50 percentile levels during susceptibility testing. One who builds a product that will

be used regularly under worst-case conditions (e.g., a highway patrol car or other vehicle with an onboard, high-power transmitter) may wish to harden to levels indicated by the 100 percentile curve.

These values may be changed as additional data are acquired, but the curves presented do have a substantial basis.

4.2 Susceptibil ity Eval uation

The levels measured around specific systems and the levels suggested for general use as guidelines

provide a basis for tests by manufacturers who wish to harden their electronic systems so as to avoid

future problems.

This hardening costs money, and overdesign adds unneeded cost. NBS is developing reliable measurement techniques and instrumentation so that manufacturers will be able to determine when they

have achieved the needed degree of hardening. We have worked with some users to develop measurement

guidelines for making the necessary measurements. At present, these measurements involve use of a TEM

cell for component testing, as suggested in the Society of Automotive Engineers Standard J1113 [4].

There are several specific factors that apply to testing anti-skid brake systems. These same factors

may or may not apply to testing other electronic systems.

The important factors in susceptibility evaluations concern uniformity of test field, increments

between test frequencies used, and time duration of the test field. Since thermal time constants of electronic braking systems are relatively lonq. one- to two-second duration test fields are needed at
each frequency. Other components and electronic circuits will have other time constants. Swept

frequency techniques are best. If they are not available, frequency increments must be carefully

chosen. Test frequencies should be incrementally changed by no more than 18 percent between 0.5 and

10 MHz, 4.8 percent between 10 and 20 MHz, 2.4 percent between 20 and 50 MHz, 1.6 percent between 50 and

150 MHz, and 1.2 percent between 150 and 1000 MHz. This calls for 310 measurements, not an excessive

number for prototype evaluation, but too many for a production unit. This frequency spacing will catch resonant circuits with a Q less than 40 at frequencies above 20 MHz. Below 20 MHz, vehicle dimensions

are small enough with respect to wavelength to reduce the probability of having resonant circuits, at least in vehicle wiring and metal work. If digital circuits are being tested, special attention should

be given to any clock frequencies.

A metallic test object causes distortions when placed in test fields. These distortions are to be expected, regardless of the test chamber. The two questions this raises in EM susceptibility testing

are:

1. Do the fields distort the same way in a test chamber as they do in their operational

environment?

2. How should the spatial variations in these perturbed fields be reported?

The answer to the first question is not known yet for TEM cells (or other enclosures). The second

question must be answered in some statistical method; which particular way is best is not clear as yet.

Present TEM cell size and frequency limitations are such that only component-sized systems may be effectively tested. No practical, reliable whole-system (vehicle) test facility is available with

present technology. Shielded rooms, anechoic chambers, and open space testing all have major

shortcomings. Until vehicle test chambers are developed, special care must be taken in testing

susceptibility of electronic components to compensate for the lack of whole-system test facilities.

Use of TEM cells at frequencies high enough to allow modes of higher order than the fundamental TEM mode is suggested. Even though measurement uncertainties become extremely large, susceptibility defects

will usually show up and often can be cured. Such misuse of a measurement system to achieve reliable,

safe vehicle operation is insignificant compared to brake failure.

A future part of this measurement program will address the interactive aspects of different sources

and modulated signals, as nonlinear effects may cause significantly different effects from a single

frequency, continuous-wave source.

A warning is necessary concerning biological hazard to personnel performing susceptibility tests. Presently accepted U.S. hazard levels are 194 volts per meter (10 milliwatts per square centimeter) as measured in the far field. Test levels from the previously suggested limits will be higher than this.

According to the ANSI Standard, the average power (proportional to E^) is averaged over a 0.1 hour

(6 minute) time interval in biological hazard calculations. Most electronic systems respond more

quickly than this. Although a TEM cell is a closed system, lead wires and cables can bring out high

level fields if they are not filtered. These fields may be dangerous to personnel or disruptive to instrumentation.

4.3 Electromagnetic Radiation Hazard to People

Many of the field strength levels measured are much higher than allowed by current ANSI Standards [5] (194 volts per meter) for personnel exposure. This could have serious implications for those who use, manufacture, and regulate these systems.

Only a few of the factors that determine these field strength levels can be controlled; the rest cause unpredictable variations in field strength levels. The most obvious factor to control is the radiated power. In some situations where maximum range or reliability of communication is required,

reduction of radiated power may not be an acceptable choice. Considerable additional work might be done

to determine whether some of these other factors may be used to reduce the field strength levels in a predictable and repeatable way, but except for reducing power levels, the other parameter variations

caused unpredictable changes.

An antenna located at the center of the roof is less hazardous to people than one located TM a fender or bumper; the presentation of data does not show this clearly.
A further consideration is that in the future the field strength levels allowed by ANSI standards

for personnel exposure may be lowered, and other mandatory standards by OSHA or EPA could be imposed.

5.0 Test Limits for Field Strength Levels

The tremendous amount of measured data was treated statistically to provide a perspective of field

strength levels that exist around vehicles.

Emphasis must be placed on the fact that these are worst-case levels. Most vehicles, most of the time, will be in environments which have field strength levels two or more orders of magntiude lower

than these covered in this report. However, many, if not most, vehicles, at some time or other, will be close to a transmitter and will be exposed to field strength levels comparable to those reported.

The judgment used in determining composite, worst-case levels as a function of frequency is not infallible. A no-risk situation may be unachievable; the objective is to achieve an acceptable,

low-risk condition. The use of a set of levels allows the designer to share in the risk-level

determination. Figure 40 shows four curves. The 100 percentile curve is high enough that all measured

values reported are equal to or less than values given by this line. Similarly, 95 percentile,

90 percentile, and 50 percentile curve brackets the corresponding measured levels.

There are two distinct susceptibility measurement problems; one is the test level; and the other is the comparability of component vs. whole-system testing. The component may be resonant at relatively high frequencies; a whole vehicle may be resonant at relatively low frequencies. The

levels either encountered or required may be the same, just at different frequencies. The higher levels

will be due to resonances, and will be "Q" times the incident, unperturbed level of field strength,

where Q is a resonance factor that relates stored energy to dissipated energy. Q's of up to 15 have

been observed in these tests. An incident, nonperturbed level of 150 volts per meter would be boosted

to 2250 volts per meter by a resonant structure with a Q of 15. If the structure is not at a resonant frequency, it will perturb the field by a 1/3 to 3 factor (e.g., an unperturbed, 150 V/m field may vary from 50 V/m to 450 V/m) at various locations, but the extreme increase in level occurs only at a resonant frequency.

One exception occurs near the base of an AM transmitter (550 kHz to 1.6 MHz) that uses a 5/8

wavelength tower. Unperturbed fields of over 800 volts per meter have been measured 3 meters from the

base of a 50 kilowatt, 5/8 wavelength transmitting tower (K0A, Parker, Colorado). Service vehicles may come within 3 meters of a transmitter tower. At AM frequencies, there should be no resonances, since even a tractor-trailer is short compared to wavelengths in the AM frequency range.

The 90 percentile test level should be sufficient to cover most cases, even though the other limits

indicate that higher field strength levels have been measured.

Susceptibility testing can be done at a component level using a TEM cell or other transmission line

structure. There may be unknown shortcomings to component testing in TEM cells; a component mounted

on a vehicle becomes electrically connected to the rest of the vehicle through cables and mounts; there are different resonant frequencies due to different sizes and shapes of structures. At present,

whole vehicle testing is not possible with practical means.

Magnetic field strength test levels are shown on the right-hand side of figure 40. These numbers

are obtained from free-space, far-field conversion (i.e., i= 376.7 = E/H). The actual numbers

measured, shown in figures 17 through 22, are comparable or less than the limits of figure 40.

Values have not yet been measured above 420 MHz, but the limit lines were extrapolated to 1 GHz. The measured decrease in levels with frequency is expected but should be verified by measurements to

1 GHz.
6.0 Summary and Conclusions

As the number of electronic systems used on vehicles increases, the need to know the

electromagnetic environment in and around these vehicles increases. This information is needed by

system designers so they can design safe electronic systems that are compatible with this

electromagnetic environment. Measurements of electric and magnetic field strength levels are reported

for the near-field levels in and around full- and compact-sized passenger vehicles and tractor-trailer

vehicles. These measurements were made with all common combinations of mobile transmitters and antennas. The rf transmitting sources used the maximum legal output power (110 W) at nominal

frequencies of 40, 162, and 416 MHz, and nominal 100-watt power levels in the HF band (3 to 30 MHz).

Illegal power levels ( 100 watts) of CB transmissions at 27 MHz were used through a special

authorization by the Interagency Radio Advisory Committee (IRAC).

Fields in and around vehicles with on-board transmitters range mostly between 10 and 300 volts per meter, with some exceptions. Field strengths in and around vehicles adjacent to vehicles with

transmitters range mostly between 5 and 100 volts per meter. Data are reported for fields on vehicles

on normally conducting ground surfaces such as concrete and asphalt as well as for vehicles on metal ground screens.

The results of the electric field strength measurements in the near-field regions of fixed,

high-power transmitters are also reported. These sites include AM, FM, and TV broadcast stations and high-power military and FAA fixed transmitters. The electric field strengths in the near-field region

of the AM broadcast station in the frequency range between 550 kHz and 1.6 MHz are found to be much

higher than those at other fixed, high-power transmitters, particularly for AM transmitters with 5/8

wavelength towers.

The curves shown in figure 40 summarize the field strength levels measured or anticipated and are suggested for susceptibility test criteria.

Some factors needed for electromagnetic susceptibility testing of components are discussed. Either

continuously swept frequency testing or closely stepped frequency testing is suggested in order to detect resonant situations which greatly increase incident field strength levels. Other important

factors are device time constants, personnel and test equipment safety, and perturbations of test fields

caused by objects under test.

Finally, worst-case field strength levels for susceptibility testing are given. These are based on measured data around vehicles. Four different levels are given in order to allow designers and manufacturers some latitude in determining the degree of electromagnetic compatibility they desire to achieve.

7.0 Acknowledgments

The authors wish to express their appreciation to the technical contract monitor, Dr. Yung Wu, of Vehicle Research Division in the National Highway Traffic Safety Administration, for his considerable

help and advice. Others -who have shown interest and given help are N. Stahler, S. Williams,

R. Radlinski, R. Testerman, and R. Woodruff, all of NHTSA.

The authors wish to acknowledge the help and cooperation of Mr. James F. Egan of the White Motor Company and Mr. Philip R. Peterson of AC Spark Plug Division of General Motors Corporation for assistance and information concerning anti-skid brake systems. We hope this cooperative attitude will continue and will help us all to a reasonable solution of these difficult problems.

We wish to acknowledge the assistance of Tom Bremer, Nancy Tomoeda, John Workman, and Connie Haagenson for their help in making many of the measurements.

8.0 References

[1] Belsher, D. R., Development of near-field electric energy density meter model EMD-2, Interagency

Agreement NI0SH-I A-74-13 U.S. Dept. of Health, Education, and Welfare (March 1975).

[2] Crawford, M. L., Generation of standard EM fields using TEM transmission cells, IEEE Trans. Electromag. Compatibility EMC-16 , No. 4 (Nov. 1974).

10
[3] Greene, F. M., Development of electric and magnetic near-field probes, NBS Tech Note 658

(Jan. 1975).

[4] Society of Automotive Engineers, Inc., Electromagnetic susceptibility test procedures for vehicle

components (except aircraft) SAE J1113 (April 1975).

[5] An American National Standard Safety Level of Electromagnetic Radiation with Respect to Personnel,

Co-Secretariat, U.S. Department of the Navy (Navy Electronic Systems Command) Institute of Electrical and Electronics Engineers, American National Standards Institute, published by Institute

of Electrical and Electronics Engineers (November 15, 1974).

11
3 3 5 2 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 O o o O o CD o o O o o o O o o o o o o o o O o o

o o o O o

i- t- s_ J- L. s- S_ l_ 0) cu cu L. 1- S- <u <D OJ cu OI o ,^ -o c -^ -CU cu 0) "O "O "O -o "O 4- C c 4- 4- c: 4- 4- 4- c 4- c 14- i»- M- 4- -o o o c C C c c: O CU 13 o o 0) o O o cu o 3 o o o o c c c

<L> CD OJ OJ 01 o 4- 1- o o 4- o O o 4- o s_ o o o o cu cu cu 4- 4- 4- 4- 4- s_

5- -M S- S- S- s- s_ s_ iS- M I_ t. s_ i- s- 4- 4-

S_ S- s- S- S_ 4- is 4- 4- 4- TO 4- 4- 4- TO «t- 4- M- 4- <t- H- L. s_ tTO (B TO TO IO O OJ o o o OJ o o o cu o o o O o O TO ttj <n

01 CU OJ cu OJ S- S_ l_ CU cu cu S- i- !_ s_ S- S- i. i. S- t- s_ S_ s- L. l_ t_ s- L. i- I- u

CU »-> 01 01 OJ +J cu <D <U 4-> cu CU OJ 0) <u cu +J +J +J t-> 4-> 4-> _cr +-> 4J u -C +J 4-» +J .c 4-> •!-> 4-> 4J *J 4-> +J (-> 4-> 4- 4- 4- 4- 4- c Cn c: c c Cn cr c C cn c c c c c c 4- <4- M0) <D CU <u <U <u OJ 01 cu cu CU 01 cu cu a> a> cu cu cu cu O) u (. u o u I- u u o S- o u (J o o u 1- •—

+J 4-> +-> u U *-> +J (-> 4-> *-> 4-> !-> *-> 4-> +J 4-> +J +-> +-> J-> +J +J 4-> 4->

c: C c c: C c c; c c c C C c c c c c c c c c c •c C < < <t < «t «s «£ < <s <t < cC < < <t <: <c <: <c < cr < < <

OJ CO CO CO 00 o co tr> ^- h cm ro

CM CM «-(

CD O IT) n *J oj ro ai rn co

CM ^ CM r-H

*3" LO ^J- I

o r- uo co cm ^h r-. co

tj- r^. id lo

CM ,-n

"H CO <t ^> ^> CM *d- CO CM OJ O N CO CJl LO «t

IO co ^- ^ to s -h CM CM ^-l

M CO LO O M

«t *t m LO O C\J H h CMCVJ OLD N LO OOOCMCO

lO H CO lO OrOCOLO

^-t —i CO CM

I*-. O »^ *d" ^D co lo r-^ co oj

«d- lo 00 «J" r-. cm co cn lo n n cri

^-l CM OJ —

f-^OlLOCTiOJ «—i CO "O CO

LO lO CM -h o N N H LO N <H rH CO CSJ ^h,-,.^ o o LO LO O lo •—i r-. N O lO CO M

CO LO N ro <*

^- O LO LO O LO

oo o> en cn ^h o i— i-H cm ro oj

(\J «t LO CO r-(

*3- LO *tf- 00 LO ro »-i i—i co oj O LO «-h O cn cn o vo

«-l ^H CM

CO -H LO CM

IO N H CO co ro i-H

CO CO LO CO CM

*a- co r^ co *d- OJ O lO OJ OJ OJ

r-H cn cn cm cm co

CM *-< CO CO CM

lo «a- lo lo CM CO CO CO OlOOOCMCO CO^frOJLOLOCO M M H CMH OJ<-h^hCOO*)^-

lit l jJ til til iii LU LU UJ l_i_l til iii iii \i\ UJ

o o o o o r-H CO .-H O r-H cn cm co «=r lo

LO LO

r-- r- r^ r^- cm oj <- cnr— r-«. i— r»* OJ OJ ^f CTi r^ r— r-» p-^. r^. cm oj -^- ^ cn

LO LO N N H hCO

«tf- cn <r> cn oj o o cm lo

^- «d" LO ^-1 CM CM LO

LO LO rH

t-H ^-i **

OJ LO CO CO r*

LO ,—

r— tO

u cu

•r- Q_

(D TO TO a "O "O T3 T3 a "O T3 T3 X 3 3 o cc c c c: C c c C C c

13 =3 3 =i 3 o •o "D T3 3 3 3 3 a "CJ -o -o T3 -o 3 T3 o o O o O c c C C o O o O c e c c c TO TO TO c O C

%. I- L. t. s_ 3 3 3 3 t- 1- t- L. 3 13 3 3 3 4-> 4-> +-> 3 s- 3

cn D) cn cn O) o o O O cn cr> cn cn O o o o O CU CU <V o cn O

J- s- !_ L. i. S- s. s_ t- e E E i- L. cn CTi cn o> cn cn cn cn cn cn cn

fd TO TO TO 03 <o TO TO <o S- S- S- TO

+-> +J 4-1 +J 4-> >. >> >> >» 4-> M 4-> •4-> >. >i >> >^ >» <D TO TO >> •!-> >>

cu 01 a> cu CU i- S- !_ t? cu CU cu <L s- s_ S- s- s- CU CU CU (. CU u

e: e: 2: s: 2: o o O o Z£. e: s: 2: o

IDu

o

TOu

o

t-TO o

TOu

o

rou

z ^ z D 5T C3

j_ i- i- s_ t- !_ t- s_ t- t- s_ s- s- X X X X X s- t- 1-

to TO TO TO IO <o TO TO TO <o TO TO (D 4-> +J -M +J 4-> <o TO TO (J u u <J o o O U O o c-> o O

0J cu CU <1J 01 u O u

cu cu 01 CU cu cu a> 01 CU IV <U a' CU D D -o -o T3 ai CU cu

rsj NJ INI N M N fsl M ha N N rsi N IM N M

(/) l/> m (^ (/) 4-> 4-' 4-> VI 1/)

1 1 1 1

t/1

1 i

<S>

i

1/1

I 1

c/l

1 (A

1 ai

L.

cu cu cu ^3

CU 10 in

1 cn

1 O

TOQ.E

TOE

O

TOt

3 3 3 3 3 TO TO TO TO TO o o o <_> <~> 3 3 O O O

u- u. u- o o o

12
ooooooooooooooo o ooooocooocoooooococo o

4- 4- "O "O O o 4- 4- 4- 4_ cccrccooccoooooo cd<dcd(dcdoocd<l>s-j-.oooo

S- S- 4- 4~ S- S- 03 TO TO TO TO O O

a) qj a c <u s~ S- S- t- S~ S- s_

TO iTJ t (O QJ (U iT3 (O

oi aj s_ s_ a> oj

S^ S_ S- s_

4-J 4- M- 4- 4- C C 4- 4- Dl DV- f- C C QjQj{uaj(U(U(u(D{D -t— -r- cu a> cd cu r— ,— ,— ,— _ U U <— f— S- S_ r— ,— (J C_> <<<<<<<<<<<<<<<

O0000 OO O 4- 4-

QJ CU (1) S- J- -c _c _c x: oj oj +J +-> +J 4_> +-> +-> 0000

<<<<<< c c c c c c

QJ <U <D (U (D 1-1 "O -O "O T3 "O 4- c c c c c o

CD CD CD CD CD O 4-4-4-4-4- S^

S- S_ S- S- S- 4-

TO TO TO rt3 TO O

CD CD <D <D <D

s- S^ i- s- s- s^

000000

+-> 4J 4-> 4_> +J +j <<<<<< a c c c c c

irjc\jtDCOiou)io«ti£)N«trMco^m

«=J-<-HOCOOLOr-Hr^.CT>kDr^.C\JC\Jt—ti—

1

CO N C»J (\j O O ^t ^ CO CO fO h

cr^^cococ\jOcoLnu">i-r>vocr»«a-Lnr^

^H _| ,_, ,—t CM 1—It—I CM —

<

«3 CM CO CO co in

f-- CTi LO «^f- LT> f-*.

MfOrH^rOCO^on^iOCOCOCOOOJ o^^fr^ooroocri^-moro^LOi-nu-)

rHrH r-lP-l(NJ rH 1HrHCO<--l^

t—I LO CM CO <-0 LO co h co in cn s

h co co in mo O lo r-- vo r-. t—

1

rococooa^crtfo^csj tJf^N'-HCOlOcOCOCTi fOr-lHOJMHCMr-lfO

ro co o cm ^o CO CO CO CO LO CM ^) fO O ID N •—1 o cm cr> CM LO

,-H _, CM r-1 <-H

•—< <X> ^J* CO LO LO 10 m n in en s

1 1 1 UJ LU UJ 1 ' r

LO LO LO LO cOHHCftc^'-iHHHiv-r^r^si— p-. CNjnnronioioioiocMCvj^t^-aicn

LO LO

r-* r^. r-~ r--. ^o lo cm cm <d- o~i r^^"d-t-Ht-Hr^r^r-^r^oocMCM'£)'sD HHCMMCMCMMCM't^^lOHH r-i _ *a- ^

TO QJ ocococococococo 3 "O ZJ "O ZJ T3 13 "O ZJ "O ZJ "O Z3 "O ZJ

cd o cd o 01 o cno en o ai o cd o cd

L. s_ u s_ s- s- i- r— CD r— C7i t— CD r— CD r— CD r— CD ^— CD ^~

iXJ TO TO TO TO TO TO TO *J >-,4-> >,4-> =», 4-> >> -fc> >> -U >"> -M >><-• (ULQjLULaJLOjLlljLlULaj z:o2:a5:oz:oz:ai:os:os:

xj 3 "o 3 "O -o c o c o c c 3 S_ 3 i_ 3 3

O O O en O O

t. S- S- SC71 r— Cn f— Cn 01

>>-!-> >i +J >> >>

1- <u i. a> i- i- d 2: o s: O D

"O "O "O "O "O "O C c C c C c 3OOOOOO 3 3 3 3 3

!_ S_ S- S- S- S- cn eft Cn Ol CT> C> >>>,>,>,>,»,

I- V J- i- V s- Q O O O Q D

1- i. s- t. «- s-

<u oj at aj <u a;

f— »o

4->4-^4->4-»4->-4->'M4-> UUUUOUUUU +->+-> 4-> -(-> a a a a 0-0.0.0.0.0-0.0-0.

uuououououuoouu OOOOOOOOOOOOOOO

Q R] <Q Q Q fl] J- 1- S- S-. L. J» -M -t-J -M +J -t-J 4->

I I I I I I t- L_ S^ U U i_

4-> 000000 4-J 4-> 4-> *-* 4-J o u o o o o

TO TO TO TO TO TO

13
5 5 3 S 5 X o o o o o o

5 3 £ O O CD SSSSS335

4- 4- C 4- 4- 4- O O O) O O O O O 4- O O O

t- s- S- S_ s- 4-4- ftJ 4- 4- 4- O O CJ O O O

01 QJ 4-> (U iU O

c: c D) c c- c

01 <u 01 cl) O) O o s_ u o o

C C C c & c

«t < <: «=c <x <c

I- 5_ S_ S- QJ 0J cu qj <u a? ~o -o _ik: _*: "O -o ~o -o c c c c

i-S_i-S_03fo4-4- IQ(Qiai00)Q)OO

<LI (1) (U (U L L

s- S- s- s» I~ s»

.— »— .— <- s_ u o

+->4->+->4->-l-J4->4->+-> cccccccc

X 3 3 5 S 3

c c o o o o

cu oj o o o o

4- 4- *~ s- s- sS- S- 4- 4- 4- 4-

<U (T3 o o o o

CD <U

S- S- S- S- s- i.

4- cr c c

+->+-> 4-> -(->+-> +-> c c c c c c

SS3S333S

oooooooo

a; cu <u s- "O "O "O QJ

s- o o o o

i. o; ai a; o

i- -i- a; c c c c

s- s- i— o o o o

+-> +j +j +j -M +J

c: c c c c c c <tinNHl^MfOCD 00 00 ^ O >£) O OOO^J**X>OlOO^h" fOpj^icvjcOrHMH CO ^ cm «sj- co vr> ^rxiHMiDnJ-i^oo

o<x>cr><x>f>e\ju">co ^- <—

*d- vo "£> cr> r^*x>r^CMcoc^ ,--oir> cri^oNLncTifoco^t n co ^) o O1 in CMcon<jnrHCOH 00<—lOOOOO CSI H O H O H r—: .—I O O —I H H (\|

-—^ ^^. ^—•-—. .-—» .*—,

,—. ^-^ (X) ro *—* -—--—* *-*• <—* CM •—^ -—^ -—- --^ CM LT) CM«a-CON^-rHC0H O CM W CO H H tHrHON^nl-lNn ^lXlCTirOlOfOM«t .—

t-n CO ^ CO 00 CT> i—I CO CO CO CO «—<r—I c\ifoocoo(\i<*oi h n in h in m C\Jr-.ocofOoo«tco

-—i-=f^>cnr^cof^-o co c\j co co -^ m *3-cncocriCsjc\ic\JLn

.-Hi—i CM O r-iOO<—i CM CO O <—( CM CM CMCMOOCMCMCOCO

CM O *t CM ^ ID

CO Lf) M t CM CM

CO o r—

r~~ o cxi o O in IO ^-i ^r CM CO ,-H in co OT CSJ ^_, ^H

r~. Oo I-* <£> O0 >-) UJ r^ *—

*—

•-H CO r-

*—

r~* >—r^. CO »H rH CM CXI r- m _, OO oo oo oo lO "3" "* CO ro en CO r^ ^H r- «* o m _, ro CJ ro r*. ro LT) CO o <~) o r\i CM in Ol CJ n ^3- ro r^ oo

CM CM ro 1-1 cm co rH •-' •xr ^r ro cm ro CO CM ^3- C\J CJ ro ro uo UD

in CO O (D N tc ID NS criLn^-irj^co t-hcoco

it s h ro n ro r-t ro in

cti id >* in «t ro r^in«c-i-

-—- o in —- in in ^~* -—« omcMr—<iom oin >—^ in co co o cm OCsicoincocMr^-r^ 0">iomror^cT> NioHr-trvrjNco

CO^Hr—iCOr-trHlOCO ^HrHr-Hr—IrHrH HhOOHHHWW

CMoocoincocMCTiT-H ? ho co s a) Hcoiniiioirosoi

rH,—iincvjmcor^po o^rj-co^-j-iOr-H inmHomoiHrf CMCOCOCMCOCOrHCM in^-J-«H/CO<rJ-in rf CJ- N fO >* fO N I

—-oo —-inocrto oocdixoo cocoinomooo OlDlOro^NCl'J OOooCO«e-J-incO IxixWH/OlHlDlD

OOf—(•-HOOrHrHf-HrH rHr-H^Hr—ICMCM ^Ht-H^HcH^HCMCOCO ooininocOrHOCM •* «t CO o •* h cococMCMCOr^ooin cocMCMtnininr^rx o o rx oo m ,—i rxr^cor^rHLOCMin M>*rj-csjnrj-mn inin^-comvo <rj-^-cocoininoooo

CMOOCOcOi-HCOIDCO H ON o C0 ID OCONinCOOlCTlCO COCOCOCMCOCMLnin CMCMCOCOCMCM ,^-COCOooCMCMCNJCsJ

hit

in in in

p^ rx rx i— i— I

CM CM cm •«*• oo en O O O CM m ID Cf •* «t ID H H HrfJCM <i- oo

r^ i— rx. px. i r~-- CMCM«rf«3-'*OlOCMCM

(CJ <U t- a.

i- >>

"O T3 TO "O TD "O C C c C c C

3 = 3333 O O O O O O

S- i- S- S- S- t- Di oi o> ct fj rji o o o a o a

CJ) CJ> CD

>> >> f^

C-o 3C3C3C CXJ C TJ "D c 03030330= 3 S-OS-OS-OOSfo+jffj+jfo+jpnj +JS_+Ji_+Jt-S-+j

oj •,- <u (- a> !- .r- <u etosoeiode:

T3 3 "O 3 "D 3 c o = o c o

3 S_ 3 S. 3 i_ O cn O cn O cn t t t

Cjn ,— CD i— Cjj ,

>) 4H >) +J >) +J t cj t u t ai o s: o s: o s:

-03 cocococo -03-O3"03

3S.3S-3S-3S- OCDOCDOCDOCD

t t t t

CD,— CD,— CD,— CJ) ,

ro ro irj rT3 >>JJ >i*J >>*J >>+> tajtutnitm de:oe:d2:oe:

oj a; qj a»

+j i—

r— ID

I- Q. E >i O 4H •!— +J X *

+j o +J x

CD O "— C (D S

1 1 1 001

IrO

1 LO l/l

1 3 3 Z3 n 3 3 3 3

ro trj ID ID

I O O O U O (J <Q IQ IS Q IQ ITJ aa aa aa E E E E E E

o o o o o o

<_>(_> CJ O O CO oooooooo "OrafOnj+j+j+J+j 0.0.0.0.0 o o o EEEE'D<0'0<0 ooooi-s-s-s- CJOOOI—1— r-l—

14
— f— to

CO CO

--. \ LO

in in lh

O

<

lo 3 3 3c

3 A _i£ -^

C\J CO OJ ^ o 3

C\J c .V cr io CT LO c

to OJ «* to o TO o c JZ o _c o c ( > o (/> (0 (/I -C >

> o > X X X X

C uo C QJ C • C

c ro c o c

* > « -I-

^O I O I —i =c =c <: ^ ^ m ^

»-t < ro >. .-< : I— I— CXL CtL en

:*: :*: ^ ±£ ^

I C\J I O I—

_ ko z: o i 3 3 «-H C3 —I <C i-h

LO C i/) c LO PO ro 03 .e c- +-> C.J c > c

to c/> (/> <u > > x > r< 3 3 3 CO > -^ > ^ 1—

,

1— h- LO

C 3 < 1 1 c > ( ) < C J < CO

>- ? < ce ce o

c e e ro

ro o w c

in i+- TO GJ

>, >, -U

14- o o o ioo

ro .—i CO e e e

>1 l»- 4- ooo o o o o

>> +-> J-> CD O O O

CD .—I E E E E

CO CO CO CO

f^ i-H

CO .—

I

.—

I

C\J LO .—I

^-< CO ^H .-H

i-l LO M CVJ

«3- .-1

r-< .-I .-( CO

i— r-. r-oooom o i-1 r-t o

r-» .-4 C\J

-— *0

f- CL

-c >,

TO TO TO TO TO TO TO u <-J U (J (J (J u

at 0) <l> a> at a> at N N NJ NJ N N| N

i 1 1 T T 1 1

I D I (I

i- f— t- r- 4-> O •»- O -r- O

+j ro .*-> ro ro o t- o J- o.

ro •*-> ro +j E

15
St

01

01

13« • M COa

00 01

a)

d - 01 o S u

Pi ,C

4-1 CO 60

pa e z <u o <u

16
b T1 « CJ

w -n B X, CO

4-1 o 3 60 • O X P.

•H !* *j 1) M U H 4-4

CCI X) S > 4-4 c o

4-J

ON o w

0> s M

r-H 01

F (1 p^

X

H CNI 4-1 > ,c

*—

cu o M-4 > <r o

01 H

u *>M

01 01

M 01 > cu. 01 4-1 01 c 4-1 a

i—10) 4-1 01 0) •H CJ

X 01

h

(-1 01 «) 01 00 a. C * U 01 4-1 4-J H -a a) u C « C U 3 O 0)

0>

O X> 4-1 i-l M C C W CD O a)

17
Fig. 3 Electric field strength levels (V/m) at various locations

around a compact vehicle on dry ground with an onboard

100 watt transmitter, 27.610 MHz, with a base-loaded

antenna located at the center of the roof top.

18
116

Fig. 4 Electric field strength levels (V/m) at various locations

around a compact vehicle on a metal ground plane with an onboard 100 watt transmitter, 27.610 MHz, with a base-loaded

antenna located at the center of the roof top.

19
48 60

Fig. 5 Electric field strength levels (V/m) at various locations

around a tractor-trailer vehicle on dry ground with an onboard 100 watt transmitter, 27.610 MHz, with a baseloaded antenna located at the center of the roof top.

20
34 82

Fig. 6 Electric field strength levels (V/m) at various near-field

locations, 110 W transmitter, 40.27 MHz, base-loaded antenna

located at the center of the roof top of the passenger vehicle, on dry ground.

21
1 I S I >

FIE. 7 - E FIELD/ FULL SIZE <BR/ HETHL GROUND FHEH (HH2)

FIE. B - E FIELD/ FULL SIZE OW/ DRY GROUND FREB (MHZ)

22
FIE. 3 - E FIELD/ CHR BESIDE TRHNSHITTINE CHR FREH (MHZ)

FIG. IB - E FIELD, FULL SIZE CHR NERR HETHL MRU. FREH <HHZ)

23
FIE. II - E FIELD/ CDHPfKT <BR/ MY GROUND FREE (MHZ)

FHEH (MHZ)

24
'

| j

- |: i

j i

i

|

! ! i lilll BT

j

: i i yjiiip {if

j

; f 1 \m ECEiJTirP -m {: -au

j!!; Sp

jit! "iT :

:

."

: : : ! Tf

: :::

[j CI

H'i.j H U ::: 1!!! : :.:

. l : 1

f lit 1 jJ

H:

: .: jjjpl

:' i ': ;

! ii!l

'.':: .1'

« . 1 1-

. ;: Iff

.::: M::;: :r

ill

....

55

1 ! ....

... .... '''' 1

'

.... ;;

ffl * Iff

' "7 ": i

\'-.~ j.f .inr a jjtj

I : | j

:

: :

:

_ : jnfinrss ji ;.; '".

. ": :: :::: :::: ; Sf m

3*

1 ! T 1 :•::: r-rh- rrrr

'::

.:':

li

: I t~i

: ij'lij TTTT:is :::: ::::

: -i:

:-;;: jHj :: rrffi mj ....

' f

j ft

:. •_ g : :: " ; ' :.:

J

" : :;;: :••; .1. 1 ; i ifp

"

•_;it ;;:! ~:r ftTT JTTt !IB W [St

': ;

.

; ft :i:i

ll:i +Hj ~

r: tlCTO

f

:::" i:i: T—

T

Tftt if iw .... n ::

1 I+-

::.:

: :

:

- ;

...

:: II] :

: .:: ...

.- 'i:;

,...

.

...

. .

.

:::.

H;i

....

4-

. . . .

. . . , ;

; ....

r

; i i 1 I B

; i i ir•B

. '

'

' 1

i 1 —r-

?

ah'

FIB. 13 - E FIELD/ TRRCTDfl-THHILER/ DRY EROJND FREE (MHZ)

1 ' ' ' 1b

1 ' '

' ' ' ' 'ita'

FIE. jH - E FIELD/ TRfKTW-TRRILER/ ICTHL ERDUND

25

\tU

FHEB (MHZ)
FIE. IS - E FIELD/ TRRC-TRHIL. BESIDE TX-CHR/ MY EHOUND FREH (MHZ)

FIB. IB - E FIELD/ THRC-TRRIL. BE5IDE TX TRBC-TRRIL/ DRY ERDUND FREH (MHZ)

26
FIB. IB - H FIELD* FULL SIZE CHR/ WW HOMO FREB (MHZ)

27
FIB. 13 - H FIELD/ COHPFKT CHR/ METHL SROUND FREB (HHZ)

< ' l_L_'

FI6. 28 - H FIELD/ CDMPBCT CHR/ DRY GROUND FREB (MHZ)

28
*

>'>' a== ffi!' — jjttti HI

sejIwtifti r ITT 1L

m

J!L E 1- w .SL.

: : ! : -1

I

' i . 25

u.i 1-

:

!

; .

:

:

: : :

: : n'lrj:

-'"•

r

:

:

:: .:.;:: JSp

:':

.

... ...

ili;.

....

:''T

::.:':

1. r- •:: 1- : 1

i F

••! ; r

.

:

:

1 if-:;' i|M TtT£ '." '

! 9-

a 1 : : I t = :!;:.; •: :• :

•

-+-?

: .!

. .

.

":

: iijj

- -H-: :' -

| §1 ::.:

::

.

: '.*

: . : .: .

1

' : :

:

::- JS

: : 4- • .

:

- ':::':

'

:

! i y

ti-N FF :-.:: ;

: ':

:

i n

pi :::: .

: :: :

• : : i :

i

i

. :

: :

t-

. . ::

, JHj . \". :

:

: : : ::. a

: I: :.L

r. ::

:

: K

::

:

: :: :::: !]?! :

: .. : - '

i

: : : :

•

:

' ::::

. :

';;

: :::

. . . "

. ..

:

: f. . ..

; :

:: ii I : i 1 1 F ! 2 J t 5 i IS!f : i i

is SIS

TIE. 21 - H FIELD, TRRCTOR TRAILER/ KETHL SROJMD FRE8 (MHZ)

FIB. 22 -

I I I

I < B H FIELD/ TRRCTOR TRRILER/ DRY BROUMD FREB (MHZ)

29
FIB. 23 - E FIELD/ HH BRDRDCH5T FRES (HHZ)

FIE. 2M - E FIELD/ HH BHDHXBST FREE (HHZ)

30
u 1 1-i I

FIG. 25 - E FIELD/ HH MOflPCRST FREH (MHZ)

FIB. 26 - C HELD, RM BROHOCBST rREB CMHZ)

31
T U I U

FIE. 27 - E FIELD/ FM 1 TV BHHXBST FREB (HHZ)

FIB. 28 - E FIELD/ FH 4 TV BHHKBST

32

FREB (HHZ)
fib. 29 - e nao/ m i tv hhqbxbst FREE (HHZ>

I IB

FIE. 30 - E FIELD/ WORST CASE/ IBB PERCENTILE

33
:? : ; i- 1; d ':': 3

eS S

--

i :» A*:

- : s^

..:-IT:= :

; ^s; T^ts; .. ^5 ----- S^: .::: :::: - i±E

s- ::u\ — ; ,;.. ; ==^\~~ —

> Erii nt ::.. ::.- i~ 1 1 is 1". - ]-

. 4

: : ; : gj=f={= s, :;!: \5h :::. :. :.t:J::

III flS=3-:m:

: iS =b!gg Er P

-.

I-

, .. -- 4-i-f-j- ~-

- -- :\rr f V

rd _ \

£- ''-' r:: -

' E

" -rrz-H—f- — - 4

=-_; 1 IT : ; -r ." ': : ::

: 1 1 3 JF g Trl?^! !sp

it

F-F F 7 J i

- ::: : ::

: : : = i : t j m^^ FF5ifflJ«C' 2-

::; ; : ; :

: :: :•:: -: ; ::

:

; "£ ^r r:3-- 1 P i

: ii;^ :;::

' :lll -— rr t Trii- -

- ::":

; ~=g ;:: -

s- =!=Pt #= — — == -j-j-rt TT ~£fc —

T=

J _ Z - :::

: : : p=j

'-

:':: e-: ._:

::::

4- ==—3 2 ilk ....

:::; ; ; r — ^ ::::

r | -_i: #35 I:;::

7~

1-

;

1 :

-Lj-U ^_i

:-.:: : r- - __ 44-lf —~i ~

— L__ _u_o. iEE ^t§| H§ HH —

-

!- 1 i

i _i : 1

zrrr

.„ _

rffij: —

;

:

1 I -~ ~ .

i

1 1+ ffi£ —rE : ;

|

:

1 1

! — *iU _* __ __ LLLLLl JJ

) I Sill)

IB

1 I I S I J I ! 1 IBB1 I < S I 1 I ! IBBB

FREfl (MHZ)

riE. 31 - E FIELD, HORST CHSEs NORMALIZED IBB PERCENTILE

L|,,,I|BB

1 ! 1 1 1 IBBi lis

FREH (MHZ)

1 1 1 ! 1 IBBB

FIB. 32 - E FIELD/ HORST CASE/ BS PERCENTILE

34
1 1 S f I I ! I 1000 FREB (MHZ)

FIE. 33 - E FIELD/ HDR5T CH5E/ NORMALIZED/ 35 PERCENTILE ^t —: -

:

' .' .:- !

: :

'

'

:

g!- ; rli "^ ==^ ~s; ir~ ftllll ,

' ; M-4

: ilflfliliiit' tH'^TIff ^ * - ' -~ :=E^E~ =

TTT frft rFiijiii I I17TTT

T

-'

: ffrp|-|l t: 11 :': :;:: :: : z_: : : -H+ -H^i i I'll !

' 'ImrWfit ; : :

:

:; :r.: :::; : TOPTITTfl 1111111

: f{ !

i J!:|ii

l! r

i rl

: -—4 ;•

=

4-|bi ffH^s^B illigl :

: :: H3

; ;

: !_[I-Iji e|? fS §!§$$

ui Ml81111~T

' tTntl.inbB Essr-~"tr—

H: E :::: : : : ;

\if -4-t-j-t- Thf iti == : : ;-

.- :..: —1 1 -i:Mo£|k^^

ft ttif flit

4ffi ~^r

- fll~^ir

-_ " t ir

£jj :~n

'ZZ

M -

li|l 'I ifflfflK-. ' 1/

' is-|4- - ; .;. :::

I

' |

i ! ]

i !!n!!'1 i: "I !

!

! 'xHJ !

I- — 1 e

1 i I' Hi 1 Nth 1

'

1 ^ftiBTffl iJfflJlil l IM l , H ini w-TIT 11 11" TM=>^S<i III

.,.. ^t^

(===111 i^"TnJ t- ';|

''

i$— a^p |?ftS|#§1 ~~—

:;;;:: = E£l^r:z^

Jj ffiiS||Spffi i j i ======

tnttiliiiiftf'^ ^f

: T

E • : " s

1 = = rriz J I Pi ^ ^ <" 4- j_i_.;f/ _.ui Ixt1: -H r* """"TTf 1 " [' HHi #4|fe - 1 tfin lea

'" — "^f^"^ #4^^^

If!** irj'i't TflfH ^nIfTtftiit; #; !

! ! '; ! n

:-:

t- i i i i i i — ".- :; ;: :::: ——

':.:: —1. 1 r ri'—

.::-

i EEEEEE

, , , j^p|t'4||^^j : y W~~ z iMM ,|l ..

:'.;

fttt I

....

a\- t IT-:-::: ±----±5H

eee:=:1

H

, ;;;. mr

::: |

:

| M "-Ill n

iffl |

I I-EEEEEE ijr - .. fflj

HI 1 j

I ±L±r •Mt X— ... 4

J

'

1 Tt t

i T 1

i it 111 :::±: ffl

,. _. rt 1

1

: . rrTftrtmttirtr mi iiiiiiiiiii __.±t..lir , 1111 II 1 . 1 i-_i.i„ , Ill, .,

!|

1 I 111)111 I II

FIB. 3H - E FlEU/ N0R5T OGE/ 9i PEfKENTILE

I 4 I I I I I I int i i i i i i i i IBM

FREB (MHZ)

35
-: : .....

Efi -L: : . : a : T '.. A< :

... | — ~: F: r_r f,

: : r: ._.. :::. :: ::

= f

i -

' § S

jg ::: • "f-i : i~r. ; :.- : ; j

!.!:

- : a***7 : : : * - : - : ..

' :::;

j |H ~ r—1~|~ r H^ : %

rs

....

~ ;::; St eg " ~-~P" t- -4-—

f-r t[4+ . m^iu. — ri ' "T T 'TIT :j-—

..;. |Ui L|+|

r

':: :z_ i*t

. ,. L. ._.:

.... — .... - br HI! - ::

::

: "7~ —• 4j- "• X^ ::

. kj+^--:+j

K|* . : ""^^^L !

' :: : :

;

: .; M j= -ll:! E %~ V'\ 1

T3 « ; : -.^r^- -i

::;: -.;] } isam Hp! :::: i:s

iiii.

j J i

~i}:': fffj:$f :::: E

::: ::: ~~-H—--- ~t::' jffi 25 TM•r: Mimrcao

I- §s^e£ frll

33=gj - - K •-:*:• :i:; i:i: :::; ::.: :;::

::;; t::: J±l| s :::: i

- ^ m

4-fT i:: Fff-

" :ti^+ 4444; :;;:

::!:

:; :; :::: ^ l!t: !:-:• :

- ^btbb1 = bb= ==ff : ?tt |b. :i::

: :: ::r. ^=EP pp ::;:

.... !lr

JjSj

:::: TC 4-rk- ±3t trtUi

-Hi- mXf I

__...t: g: || IE ^;p

!- ' " T t ' -

!

T^" -^"—

<

•*- i£j•"3 $ =p=b= —

f— +—1-+- -p*J #e

lly. ft *1

^

1 —

tt^ .lul j|l}| --—+- Stt 1

"~*~!'

| "*~*" nil

\

', [[' :::: ::: „. : jjb. J~: t^ii --T-- ffl

'II

i t,t II N.

i _i_... 1

! !!

i J- i itt m

1 4(J

j !'| l|

! 111! ill 1 illi .11 ^J. 1 Ji II 1- ::::imi LUI ^illi -

—

1

! J I i I 1 I I I 1 IB

FIE. 3S - E FIELD, HOKST CRSE/ NORMALIZED/ 9 PERCENTILE

1 S 1 1 1 ! 1 IBB: lis

FREB (MHZ)

i i i i i

I IB

FIB. 3B - E FIELD/ HDR5T CASE/ 7S PERCENTILE

36
——, -i —"'["" * -I =j (j^^ ~

j/\< P

^N, ::.: :;::

1

. z

2:": -- : : : :

:

1 :;::!-:: : :::

: : -r <- si F ^ : :;-: :'- :----: * ;"

: ;

-

j

'-[z-. _'--:' : 5~^ c Lil. 1 :rE ;

. . :

; :: : :::: TTrh>Z rtz~

:;;: :r: r- :

:

; V£ ^

X ~-:

T /v ; - IT j iprit __4

""IT _Ui_ raF

E ; ;

i:

.. ... ... 1 ... — 1*1. i: ^\ ::: -- .._ -- N

SJ .... --• .... lUi£ ...- ——

.... ^ sr —

Z

.... -Ui-*- -l-i+j- ~:~ "T" *Ht r. —

J ~ \- -7 = l =— ;

"

: gg

& s.

si a i

i N si : :X :. .

'=

: 1 :-

|

"* N

-

- : :{ : ::: 3 "n

s

-.::;: i- - —

... ! £3 ¥

\. m

^juv^aLZEir

i- is r ,'i ,

- _ :

.

:

- - 33 = —i-f — lip

"• yfr

i- -r ::

',''.'

; — Sf4f HS :-:.? ;.;.

; , —

TTTJ

: : - ^^

*^??S e» • s

:,.

i-

. . .

:

EH -

I -- —

H-f-^r M -i . . . . . L

TrTf ~H IL-- 3B13»[ESS

—t ,4 i- —-TM IE - :; ±Q.

..... -^ ....

~1 _-

~~ ~~~~ i|Tf r

1

^

' 1

:

1

-U-4--+—

.... -... Ffl U!j||| — — —— | — — ----

ill 1 1 ii !| 1 —

1

^LHi. III Mil Jam.-i. — —

,

— J4 i i 1 I ! 1 IB

I S I 1 I ! 1 IBB

i i < iiiiii

IBBB FREH (KHZ)

FIB. 37 - E FIELD/ H0R5T CB5E/ NORMALIZED/ 7S PERCENTILE

FIE. 38 - E FIELD/ HOHST OBu SB PERCENTILE

37
<W/A> 3

38
S3' Z 1*7 tf> in

NX

E3

UJ

EK

U. P

in

UJainIE

00I UJ

IKUJa.

>. <szic

UlI

in

u.

H»

<H/A> 3

39
NBS-114A (REV. 9-78)

_ . " "" '

' " U.S. DEPT. OF COMM. 2. Gov't Accession Ho, BIBLIOGRAPHIC DATA

SHEET

1. PUBLICATION OR REPORT NO. NBS TN-1014

4. TITLE AND SUBTITLE

Electromagnetic Interference (EMI) Radiative Measurements

for Automotive Applications

5. Publication Date June 1979

$. Performing Oigamzation Code

7. AUTHOR(S) J. W. Adams, H. E. Taggart, M. Kanda, and J. Shafer

8. Performing Organ. Report No.

9. PERFORMING ORGANIZATION NAME AND ADDRESS

NATIONAL BUREAU OF STANDARDS

DEPARTMENT OF COMMERCE

WASHINGTON, DC 20234

16. ^Js^t/TasMlfor* l*sii8o*

11. Contract/Grant No.

12. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (Street, City, State, zip)

Department of Transportation

National Highway Traffic Safety Administration

Washington, D.C.

13. Type of Report & Period Covered

15. SUPPLEMENTARY NOTES

|

| Document describes a computer program; SF-185, FIPS Software Summary, is attached.

16* ABSTRACT (A 200-word or less factual summary of most significant information. If document includes a significant bibliography or

literature survey, mention it here.) This report describes the measured results of the electromagnetic (EM)

environment encountered by three different-sized vehicles exposed to a selection

of CB and mobile radio transmitters and broadcast stations. The vehicle in these

situations is immersed in the near field of the radiating signals and the measured

data is near-field data. This report gives measured data of electric and magnetic

fields measured independently. The purpose of the report is to identify the EM

environmental conditions under different circumstances in order to estimate EMC

testing criteria for vehicles and their electronic systems.

17. KEY WORDS (six to twelve entries; alphabetical order; capitalize only the first letter of the first key word unless a proper name;

separated by semicolons)

Mobile-radio; near-field strength levels; vehicular electromagnetic environment;

vehicular near-zone electric fields; vehicular near-zone magnetic fields; worstcase EM fields.

18. AVAILABILITY (3 Unlimited

I I For Official Distribution. Do Not Release to NTIS

[X] Order From Sup. of Doc, U.S. Government Printing Office, Washington, DC

20402, SD Stock No. SN003-003- 02086-9

I I Order From National Technical Information Service (NTIS), Springfield, VA. 22161

19. SECURITY CLASS

(THIS REPORT)

UNCLASSIFIED

20. SECURITY CLASS

(THIS PAGE)

UNCLASSIFIED

21. NO. OF

PRINTED PAGES

48

22. Price

$1.80

USCOMM-DC
I For a review copy, write Journal of

I Research, National Bureau of Standards,

I U.S. DEPARTMENT OF COMMERCE

Washington, D.C. 20234

Subscribe now -

The new

National Bureau

of Standards

Journal

The expanded Journal of Research of the National

Bureau of Standards reports NBS research and

development in those disciplines of the physical

and engineering sciences in which the Bureau is active. These include physics, chemistry, engineering, mathematics, and computer sciences. Papers

cover a broad range of subjects, with major

emphasis on measurement methodology, and the

basic technology underlying standardization. Also

included from time to time are survey articles on

topics closely related to the Bureau's technical and scientific programs. As a special service to subscribers each issue contains complete citations

to all recent NBS publications in NBS and non- NBS media. Issued six times a year. Annual subscription: domestic $17.00; foreign $21.25. Single

copy, $3.00 domestic; $3.75 foreign.

• Note : The Journal was formerly published in two sections: Section A "Physics and Chemistry" and Section B "Mathematical Sciences."

NBS Board of Editors

Churchill Eisenhart,

Executive Editor (Mathematics)

John W. Cooper (Physics)

Donald D. Wagman (Chemistry)

Andrew J. Fowell (Engineering)

Joseph O. Harrison (Computer Science)

Stephen J. Smith (Boulder Labs.)

Subscription Order Form

Enter my subscription to NBS Journal of Research

at $17.00. Add $4.25 for foreign mailing. No additional postage is required for mailing within the United States or its possessions.

Send Subscription

UC id

to: W

Name-First, Last

1 1 1 1 1 1 II 1 1 1 II 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

1 1 1 1 1 1

Company MM Name or Additional Address Line

1 1 1 1 II 1 1 1 II II Mill

-A. 1 1 1 I

| MM Street Address

II 1 II II 1 1 1 II II II 1

City

1 1 II 1 1 1 1 1 1 1 1 1 1 1

State

1

Zip Code

1 II 1

Remittance Enclosed (Make checks payable

to Superintendent of Documents)

Charge to my Deposit Account No.

MAIL ORDER FORM TO:

Superintendent of Documents

Government Printing Office Washington, D.C. 2O402

frU.S. GOVERNMENT PRINTING O FFIC E: 1 9 79-0-6 77-07 2/ 1 2 88

NBS TECHNICAL PUBLICATIONS

PERIODICALS

JOURNAL OF RESEARCH—The Journal of Research

of the National Bureau of Standards reports NBS research and development in those disciplines of the physical and

engineering sciences in which the Bureau is active. These

include physics, chemistry, engineering, mathematics, and

computer sciences. Papers cover a broad range of subjects, with major emphasis on measurement methodology, and

the basic technology underlying standardization. Also in- cluded from time to time are survey articles on topics closely

related to the Bureau's technical and scientific programs. As

a special service to subscribers each issue contains complete

citations to all recent NBS publications in NBS and non- NBS media. Issued six times a year. Annual subscription: domestic $17.00; foreign $21.25. Single copy, $3.00 domestic; $3.75 foreign. Note: The Journal was formerly published in two sections: Section A "Physics and Chemistry" and Section B "Mathematical Sciences." DIMENSIONS/NBS

This monthly magazine is published to inform scientists, engineers, businessmen, industry, teachers, students, and

consumers of the latest advances in science and technology, with primary emphasis on the work at NBS. The magazine

highlights and reviews such issues as energy research, fire protection, building technology, metric conversion, pollution

abatement, health and safety, and consumer product per- formance. In addition, it reports the results of Bureau pro- grams in measurement standards and techniques, properties of matter and materials, engineering standards and services, instrumentation, and automatic data processing.

Annual subscription: Domestic, $11.00; Foreign $13.75

NONPERIODICALS

Monographs—Major contributions to the technical liter- ature on various subjects related to the Bureau's scientific and technical activities. Handbooks—Recommended codes of engineering and industrial practice (including safety codes) developed in cooperation with interested industries, professional organizations,

and regulatory bodies. Special Publications—Include proceedings of conferences sponsored by NBS, NBS annual reports, and other special

publications appropriate to this grouping such as wall charts, pocket cards, and bibliographies.

Applied Mathematics Series—Mathematical tables, manuals, and studies of special interest to physicists, engineers,

chemists, biologists, mathematicians, computer programmers,

and others engaged in scientific and technical work.

National Standard Reference Data Series—Provides quantitative data on the physical and chemical properties of

materials, compiled from the world's literature and critically evaluated. Developed under a world-wide program co- ordinated by NBS. Program under authority of National Standard Data Act (Public Law 90-396).

NOTE: At present the principal publication outlet for these data is the Journal of Physical and Chemical Reference Data (JPCRD) published quarterly for NBS by the American Chemical Society (ACS) and the American Institute of Physics (AIP). Subscriptions, reprints, and supplements

available .from ACS, 1155 Sixteenth St. N.W., Wash., D.C.

20056.

Building Science Series;—Disseminates technical information developed at the Bureau on building materials, components,

systems, and whole structures. The series presents research

results, test methods, and performance criteria related to the

structural and environmental functions and the durability and safety characteristics of building elements and systems. Technical Notes—Studies or reports which are complete in themselves but restrictive in their treatment of a subject.

Analogous to monographs but not so comprehensive in scope or definitive in treatment of the subject area. Often

serve as a vehicle for final reports of work performed at NBS under the sponsorship of other government agencies.

Voluntary Product Standards—Developed under procedures

published by the Department of Commerce in Part 10, Title 15, of the Code of Federal Regulations. The purpose

of the standards is to establish nationally recognized require- ments for products, and to provide all concerned interests with a basis for common understanding of the characteristics of the products. NBS administers this program as a supple- ment to the activities of the private sector standardizing

organizations.

Consumer Information Series—Practical information, based on NBS research and experience, covering areas of interest

to the consumer. Easily understandable language and

illustrations provide useful background knowledge for shopping in today's technological marketplace.

Order above NBS publications from: Superintendent of Documents, Government Printing Office, Washington, D.C.

20402. Order following NBS publications—NBSIR's and FIPS from

the National Technical Information Services, Springfield, Va. 22161.

Federal Information Processing Standards Publications (FIPS PUB)—Publications in this series collectively constitute the Federal Information Processing Standards Register.

Register serves as the official source of information in the Federal Government regarding standards issued by NBS

pursuant to the Federal Property and Administrative Services Act of 1949 as amended, Public Law 89-306 (79 Stat. 1127), and as implemented by Executive Order 11717

(38 FR 12315, dated May 11, 1973) and Part 6 of Title 15 CFR (Code of Federal Regulations).

NBS Interagency Reports (NBSIR)—A special series of

interim or final reports on work performed by NBS for outside sponsors (both government and non-government).

In general, initial distribution is handled by the sponsor;

public distribution is by the National Technical Information

Services (Springfield, Va. 22161) in paper copy or microfiche form.

BIBLIOGRAPHIC SUBSCRIPTION SERVICES

The following current-awareness and literature-survey bibli- ographies are issued periodically by the Bureau: Cryogenic Data Center Current Awareness Service. A litera- ture survey issued biweekly. Annual subscription: Domestic, $25.00; Foreign, $30.00.

Liquified Natural Gas. A literature survey issued quarterly.

Annual subscription: $20.00.

Superconducting Devices and Materials. A literature survey

issued quarterly. Annual subscription: $30.00. Send subscription orders and remittances for the preceding bibliographic

services to National Bureau of Standards, Cryogenic Data

Center (275.02) Boulder, Colorado 80302.
U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards

Washington, DC. 80234

OFFICIAL BUSINESS

Penalty for Private Use, S300

POSTAGE AND FEES PAID

U.S. DEPARTMENT OF COMMERCE

COM-218

SPECIAL FOURTH-CLASS RATE

.

BOOK

1298