3EPA 

United States Air and Radiation 400R·9'2-ooo 

Environmental Protection (NAREL) July 199'2 

Agency 

Measurements of Electric 

and Magnetic Fields in the 

Waianae, Hawaii Area 
MEASUREMENTS OF ELECTRIC AND MAGNETIC FIELDS 

IN THE WAIANAE, HAWAII AREA 

JULY1992 

Edwin D. Mantiply 

National Air and Radiation 

Environmental Laboratory 

1504 Avenue A 

Montgomery, AL 36115-2601 

U.S. Environmental Protection Agency 

Office of Radiation Programs 
EXECUTIVE SUMMARY 

During November 27-30, 1990, the U.S. Environmental Protection Agency 

(EPA) conducted a measurement survey of electric and magnetic field levels along the 

southwest coast of Oahu, Hawaii. These measurements were requested by the State 

of Hawaii to determine the levels of radiofrequency (RF) electric and magnetic fields 

near Naval radio transmitters at LualualeL The objective was to determine maximum 

fields in residential areas. This report documents the measurement results. Also, a 

few measurements were made of extremely-low-frequency (ELF) electric and magnetic 

fields at 60 hertz, the frequency used for electrical power. 

Radiofrequency (RF) fields due to operation of the Lualualei Naval transmitters 

were measured in three frequency bands: very-low-frequency (VLF), low-frequency 

(LF), and high-frequency (HF). Just outside the Navy site boundary, maximum 

measured RF electric fields were 82, 0.5, and 8.8 volts/meter (V/m) in the VLF, LF, 

and HF bands, respectively; maximum measured RF magnetic fields were 99, 0.9, and 

22 milliamps/meter (mAim) in the same three bands. The VLF and LF transmitters 

operate continuously and the HF transmitters operate intermittently. For the VLF 

case, measurements were made near the boundary of the transmitter facility and 

along the coastal highway as a means to bracket the likely range of fields in the area 

in between. VLF fields ranged from 0.15 V/m to 82 V/m for the electric field and 2.5 

to 99 mA/m for the magnetic field. Because of the limited dynamic range of the 

iii 
equipment, the maximum LF field measured is probably somewhat less than the 

actual maximum LF field outside the site boundary. The maximum measured level of 

60 Hz ELF magnetic and electric fields in the Waianae area were 15 milligauss {mG) 

and 30 V/m. ELF magnetic fields are generally reported in units of milligauss (mG) 

while RF magnetic field are reported in units of milliamps per meter (mAim). For 

practical purposes 1 mG = 80 mAim. 

iv 
CONTENTS 

Preface 

Acknowledgments 

Figures 

Tables 

1. Introduction 

2. Equipment and Methods 

2.1 VLF and LF Equipment and Methods 

2.2 HF Equipment and Methods 

2.3 ELF Equipment and Methods 

3. Results and Discussion 

3.1 RF Results 

3. 1 . 1 VLF Results 

3.1.2 LF Results 

3.1.3 HF Results 

3.2 ELF Results 

3.3 Discussion 

4. Conclusions and Recommendations 

References 

Appendix: Calibration Data 

v 

vii 

ix 

xi 

xlii 

1 

3 

4 

8 

8 

10 

10 

13 

22 

25 

29 

33 

34 

35 

36 
PREFACE 

We believe the accuracy of the measurements made in this study is high because 

of the appropriateness of the measurement approach and because the degree of 

instrument uncertainty was low. Since the purpose of the study of electric and 

magnetic fields at Lualualei was to determine the ~~maximum" fields to which an 

individual could be exposed, a statistical sampling approach to measurement was 

unnecessary. The relatively small area outside the Navy property and closest to the 

antennas could be probed confidently with a field survey meter for the maximum 

potential levels. 

Moreover, the fact that the antennas under study generated fields that were 

constant, that radiated equally in all directions, and that decreased in intensity with 

distance allowed measurements sites to be selected with a great degree of freedom, 

so long as objects that might perturb measurements (introduce shadows and 

reflections) were avoided. Because these perturbations were avoided whenever 

possible, we are confident "maximum" fields were measured. Finally, instrument 

uncertainty, always a factor affecting the accuracy of field measurements, was within 

ten percent of the measured values in this study. 

vii 
ACKNOWLEDGMENTS 

The support of transmitter operators and Navy specialists in field measurements 

allowed the study to proceed smoothly. Arnold Den and Shelly Rosenblum of EPA 

Region 9 provided field support. Toni West, an electrical engineering undergraduate 

student employed at Environmental Protection Agency-Las Vegas, calibrated 

instruments, corrected raw data, generated rough maps and plots, provided 

background information in early drafts, and assembled the report. Richard Levy 

contributed statistical analyses and the resultant graphics. EPA reviewers included 

Shelly Rosenblum, Dr. Doreen Hill, Lynne Gillette, and Norbert Hankin. External peer 

reviewers included Dr. Keith Florig, Research for the Future, Paul Gailey, Oak Ridge 

National Laboratory, David Janes, Risk Analysis Corporation, Dr. Raymond Neutra, 

State of California, and Richard Tell, Richard Tell Associates. 

ix 
FIGURES 

Number Page 

1 Whip Antenna System 6 

2 Study Area 11 

3 Naval Radio Transmitter Facility at Lualualei 12 

4 VLF Results 14 

5 VLF Measurement Traversing Power Lines 19 

6 VLF Electric Field Histogram and Smoothed Data 21 

7 VLF Magnetic Field Histogram and Smoothed Data 21 

8 LF Results 23 

9 LF Electric Field Histogram and Smoothed Data 24 

10 HF Results Along Lualualei Homestead Road 27 

11 Variation in Electric and Magnetic Fields in Front of Rhombic Antenna 28 

12 HF Electric Field Histogram and Smoothed Data 29 

13 HF Magnetic Field Histogram and Smoothed Data 29 

14 ELF Results 30 

15 ELF Electric Field Histogram and Smoothed Data 32 

16 ELF Magnetic Field Histogram and Smoothed Data 32 

xi 
TABLES 

Number Page 

I Field Calibration of Whip Antenna System 7 

2 VLF Results 15 

3 VLF Measurements During Reduction of Power 20 

4 LF Results 22 

5 HF Results 25 

6 ELF Results 31 

7 Maximum Fields Measured During Study 34 

xiii 
1. INTRODUCTION 

At the request of the Hawaii Department of Health, the U. S. Environmental 

Protection Agency (EPA) Office of Radiation Programs- Las Vegas Facility and EPA 

Region 9 measured electric and magnetic fields in the Waianae area along the 

southwest coast of Oahu. The Hawaii Department of Health and members of the 

public were concerned that electric and magnetic fields generated by the nearby 

Lualualei Naval Radio Transmission Facility might be relevant iactors in a larger State 

investigation of childhood cancer cases found in the area. Other environmental 

agents, such as chemical contamination, are also being investigated by the Hawaii 

Department of Health. 

The electric and magnetic field sources of interest in this study were the radio 

transmission antennas at the Lualualei Naval Radio Transmission Facility. The Naval 

Facility operates high-power transmitters at 23.4 kilohertz (kHz) in the very-lowfrequency (VLF) range, at 146.1 kHz in the low-frequency (LF) range, and at various 

frequencies in the high-frequency (HF) or shortwave range of 3 to 30 megahertz 

(MHz). The VLF and LF transmitters operate continuously and the HF transmitters 

operate intermittently. 

This study was designed to determine fields in residential areas ior the limited 

1 
range of frequencies due to the operation of transmitters at the Lualualei Naval facility. 

The results of measurements and the equipment and methods used in the study are 

described in this report. Measurement instruments capable of determining electric and 

magnetic fields in the frequency bands of VLF, LF, and HF were used. Several of the 

instruments overlap more than one band. 

In addition, some measurements of electric and magnetic fields at the extremelylow-frequency (ELF) of 60 hertz were made to explore whether any unusual 

circumstances existed with respect to power lines. Power lines operate at 60 cycles 

per se,cond or hertz (Hz) in the ELF frequency range. Instruments capable of 

measuring in the ELF frequency band were also used in this study. 

2 
EQUIPMENT AND METHODS 

The equipment used for electric and magnetic field measurements is matched to 

the frequency of the field source under study. Each measurement device or system 

has a frequency range over which it is calibrated and operates properly. These 

instruments not only respond to fields over the specified frequency range but can also 

respond to fields outside this range. If the frequency cannot be determined with an 

instrument (usually the case with survey meters), it can be difficult to determine the 

source of the field causing the instrument response. For example, a radiofrequency 

electric field survey meter will respond to strong ELF electric fields in addition to the 

intended radiofrequency response. One approach to identifying the source of an 

instrument response is to control the source presumed to cause the response. For 

example, if the power of a transmitter is reduced and the meter reading drops 

accordingly, then the transmitter being controlled is the cause of the instrument 

response. In a case where the frequency can be determined with an instrument, the 

field source can be positively identified from the frequency if no other sources 

operating on the same frequency are present. Both frequency readout and power 

control approaches were used to identify field sources in this study. It should be 

noted that all of the instruments used in this study were single-axis type; that is, only 

the vector component of the field that is aligned with the instrument sensor or antenna 

was determined. In all cases the sensor axis was oriented to obtain a single maximal 

response. 

3 
1 VLF and LF Equipment and Methods 

The same equipment was used to measure both VLF and LF fields. Electric 

fields were measured with two Model EFS-1 meters manufactured by Instruments for 

Industry and designed to operate over the frequency range of 10 kHz to 200 MHz. 

These instruments were calibrated using a transverse electromagnetic (TEM) cell in 

EPA's Montgomery laboratory [1]. Calibration data for the Instruments for Industry 

meters are located in the Appendix. These instruments have certain limitations: they 

measure only electric fields; do not measure frequency; may be susceptible to 

interference from power line ELF electric fields; and have limited sensitivity. To 

overcome some of these limitations, special measurement systems were assembled 

and used as described below. 

Magnetic fields were measured with an Eaton Model 94605-1, 51

/ 4-inch loop 

antenna connected to a Tektronix Model 212 battery-powered oscilloscope through a 

50 ohm load resistor. The manufacturer's calibration curve for the 51;4-inch loop is 

given in the Appendix. Correction factors for the loop and oscilloscope system were 

determined with a TEM cell; these factors were used to convert oscilloscope readings 

in millivolts peak-to-peak (mV p-p) to magnetic field in root-mean-square 

milliamps/meter (mAim). The results of the TEM cell calibration are also shown on the 

figure in the Appendix and are in good agreement with the manufacturer's curve. The 

4 
magnetic fields were measured at locations away from any vehicles or other large 

conducting objects, orienting the loop for maximum response, and reading the 

oscilloscope for either the VLF or LF waveforms (see discussion below). The 

polarization of the magnetic field was always horizontal, as expected, based on the 

transmitting antenna geometry. 

To measure electric fields and frequency, a standard magnetic mount whip 

antenna about one meter long was attached to the top of a rental car and calibrated in 

the field (see Figure 1 ). In this arrangement, the entire vehicle becomes part of an 

electrically-small capacitive antenna system. The standard antenna cable was 

replaced with a six-foot section of low capacitance cable (RG 62 A/U) to reduce 

capacitive loading and increase sensitivity. This cable was connected to both the 

oscilloscope and a Fluke Model 8060A digital voltage and frequency meter located 

inside the vehicle. The system was calibrated in the field by approaching either the 

VLF or LF transmitting antennas on the Navy site so that the field from either antenna 

was dominant; reading the oscilloscope ln the vehicle; and measuring the electric field 

with both EFS-1 meters at the same location without the vehicle present The 

EFS-1 field readings (corrected and averaged) divided by the oscilloscope readings 

become the calibration factor for the system. The VLF transmitter was shut down for 

maintenance during the LF calibration. The VLF calibration was rechecked twice 

during the study and the results are given in Table 1. The calibration factor did not 

change significantly from VLF to LF frequencies. Proper readings with the whip 

5 
Figure 1. Whip Antenna System 

6 
system depend on the electric field being vertical and uniform near ground. For open 

areas, this is a reasonable assumption for electric fields at VLF and LF frequencies 

and is supported by the EFS-1 measurements. In processing the data, only the first 

VLF calibration factor (1 0.19) was used, as it was obtained in a more open area. 

TABLE 1. FIELD CALIBRATION OF WHIP ANTENNA SYSTEM 

Calibration Averaged EFS-1 Oscilloscope Reading Factor 

Frequency Field (V/m) (V p·p) (V /mrmsN p.p) 

(kHz) 

146.1 8.63 .84 10.27 

23.4 8.15 .8 10.19 

23.4 54.93 5.2 10.56 

23.4 51.45 5.2 9.89 

The whip system not only responds to VLF and LF electric fields generated by 

the Navy transmitters, but also responds to 60 Hz ELF electric fields due to power 

lines. The system could be used for ELF electric field measurements but was not 

calibrated at 60 Hz for this study. The voltmeter reading is only useful when one 

frequency is dominant; however, the oscilloscope display can be used to distinguish 

the contribution from sources at different frequencies. The oscilloscope may display 

up to three sinusoidal waveforms superimposed on top of each other. The fast LF 

waveform "rides on top of" the slower VLF waveform and the LF and VLF combined 

are on top of the much slower ELF waveform. Careful triggering and reading of the 

7 

• 
oscilloscope allows the peak-to-peak voltage due to each of the waveforms to be 

measured separately. An advantage of the whip system is that it allows continuous 

observation of electric field variations while driving from one measurement location to 

the next. This characteristic allowed us to observe and document any unusual field 

variations between measurement sites. 

2.2 HF Equipment and Methods 

The HF electric field measurements were made using Instruments for Industry 

EFS-1 survey meters. Magnetic fields at HF were measured using an Eaton Model 

92200-3, 15-inch loop antenna connected to a Hewlett Packard Model 8482A power 

sensor and Hewlett Packard Model 4358 battery-operated radiofrequency power 

meter. The manufacturer's calibration data for the 15-inch loop are included in the 

Appendix. These data are used to derive an algorithm to convert power meter 

readings to magnetic field strength in milliamps per meter (mA/m). 

2.3 ELF Equipment and Methods 

Two ELF survey meters were used in the study. A Monitor Industries Model 

428-1 was used to measure 60 Hz magnetic fields and an Electric Field 

Measurements Company Model 116 plus-2-60-2-300 was used to determine 60 Hz 

8 
electric fields. Both instruments have been tested at EPA and are accurate to 

± 5 %. The objective of these measurements was to determine the upper limits of 

fields due to power distribution lines in residential areas. Therefore, measurements 

were made close to distribution lines but not made inside residences. Generally, a 

single intersection in a neighborhood that had numerous overhead power distribution 

lines was chosen. The area of the intersection was probed until a maximum reading 

was found at any height from zero to two meters above ground. 

9 
3. RESULTS AND DISCUSSION 

Figure 2 shows the area of study along the southwest coast of Oahu, Hawaii, 

from Makaha to Nanakuli. Sources of electric and magnetic fields include the radio 

transmitters at the Lualualei Naval facility and overhead power lines. 

3.1 RF Results 

Radiofrequency (RF) electric and magnetic fields were measured at the VLF, 

LF, and HF frequencies of Naval transmitters at Lualualei. Figure 3 shows details of 

the Lualualei transmitter facility. Two towers at the south end of the facility support 

the VLF transmitting antenna system operating continuously at a power of 512 

kilowatts (kW) and a frequency of 23.4 kHz. Four towers nearby in a triangular 

arrangement (one in the center) support the LF antenna system operating 

continuously at a power of 50 kW and a frequency of 146.1 kHz. Many HF antennas 

are located toward the northern end of the facility. These HF antennas can operate 

intermittently at a variety of frequencies in the 3 to 30 MHz band at a maximum power 

of 10 kW on any one antenna. The transmitter operating powers were confirmed by 

maintaining communication with the operators of the Navy facility during the study 

period. Also, a lower power Coast Guard transmitter operating at a medium-frequency 

(MF) between 0.3 and 3 MHz exists at the eastern end of the site (not shown). 

10 
Kaena 

Point 

Naval Radio 

Transmitter Facility (NRTF) ...;._......, 

Barbers 

Point 

I I 

Kahuku Point 

Figure 2. Study Area 

11 

Makapuu 

Point 
HFAntennas 

0 Rhombic 

@ Inverted Cone 

+ Rotatable Log Periodic 

0 High Take·off Angle 

A Vertical Doullet 

(5? Conical Monopole 

~ Broadband Dipole 

@ @ 

+ 

A 

"b Edison Street 

O 800 FEET 

EM~w""t:!'iiiliil!~~al' 400 
The MF transmitter was not studied because the eastern boundary is not publicly 

accessible. 

3.1.1 VLF Results 

VLF (23.4 kHz) electric and magnetic fields were studied much more 

intensively than fields at other frequencies because of the high power of this 

transmitter. Measurements were made along roads which were on the perimeter of 

the Lualualei facility and along the coastal highway. The maximum off-site field 

strengths should occur near the perimeter of the facility and the highway 

measurements should include the minimum field strengths in the area studied. 

Measurements were also made along Waianae Valley Road to the north of the site. 

The results of these measurements are displayed on the map in Figure 4. Along the 

perimeter roads electric fields varied from 0.15 to 61 V/m and magnetic fields varied 

from 4.9 to 92 mAim. Values of fields along the coastal highway were from 0.17 to 

1.5 V/m for the electric field and 2.5 to 9.2 mAim for the magnetic field. These 

measurements were made using the 5%-inch loop and whip antenna system with the 

oscilloscope. Table 2 lists all of the VLF results. Note that the maximum VLF electric 

field of 82 V/m was observed in an open area between residences south of lliili Road. 

This value was found by searching the area for a maximum that was not perturbed by 

vegetation or power lines. 

13 
,_, \ 

Pacific 

Ocean 

1.0 MILE 0~~~0~.5-~ 

Usedwn, ..... 11 permission. cop yrlght J.R. Clete 

F1gure . 4 · VLF Results 

14 

o.61 Vlm~l 3.7mAim \ 

o 17 VIm 

4:9mA!m\ 
TABLE 2. VLF RESULTS 

DESCRIPTOR 

Paakea Road from Mailiilii Road to 

lliili Road 

(measurements taken every 0.1 mileelectric field only) 

lliili Road from end to 

Paakea Road 

(measurements taken every 0.1 mile) 

MailiiiH Road continuing on Lualualei 

Homestead Road from Paakea Road to Fence Road 

(measurements taken every 0.2 mile) 

15 

ELECTRIC 

FIELD (V/m) 

.61 

1.5 

1.7 

3.5 

1 

5.1 

5.1 

6.1 

5.6 

5.1 

12 

15 

15 

12 

16 

16 

12 

15 

12 

51 

56 

61 

51 

39 

20 

2 

.15 

.71 

.71 

.71 

.61 

MAGNETIC 

FIELD (mAim) 

62 

86 

77 

71 

68 

31 

4.9 

7.4 

11 

15 

12 

continued on next page 
TABLE 2 -- Continued 

DESCRIPTOR 

Kaukama Road from Paakea Road to end 

(measurements taken every 0.2 mile) 

Farrington Highway from Makaha Valley Road to 

Kahe Power Plant 

(measurements taken every 0.5-0.7 mile) 

ELECTRIC 

FIELD (V/m) 

1.5 

1.2 

1.1 

1.7 

1.8 

.61 

14 

9.7 

1.7 

5.1 

.41 

.45 

.36 

.41 

.61 

1 

1 

1.5 

1.5 

1 

.61 

1 

1.1 

.61 

.17 

.41 

.51 

MAGNETIC 

FIELD (mAJm) 

11 

12 

11 

12 

11 

8.6 

6.2 

92 

57 

40 

9.2 

2.5 

2.5 

3.7 

3.1 

3.7 

4.9 

9.2 

8 

6.8 

6.2 

6.2 

6.2 

5.5 

3.7 

4.9 

2.5 

2.5 

continued on next page 

16 
TABLE 2 -- Continued 

DESCRIPTOR 

Waianae Valley Road and Haleahi Road Intersection 

0.55 mile west from Haleahi Road on Waianae 

Valley Road 

Punanaula Street and Kaneaki Street 

0.55 mile west from Kaneaki on Waianae Valley Road 

Momona Place and Waianae Valley Road Intersection 

Dead end of Hakimo Road 

going toward Paakea Road 

(measurements taken every o. 1 mile) 

ILIILI TRAVERSE 

0.2 miles from end of lliili Road 

going into field perpendicular to lliili Rd. 

(not shown on map) 

(measurements taken every 20 meters) 

APANA TRAVERSE 

Paakea Road and Apana Road Intersection 

going parallel to Apana Road 

(measurements taken every 5 meters) 

(not shown on map) 

17 

ELECTRIC 

FIELD (V/m) 

.66 

.41 

.92 

.41 

.61 

1.3 

8.2 

11 

7.7 

6.1 

3.1 

24 

64 

72 

75 

75 

72 

63 

57 

60 

52 

47 

45 

24 

14 

26 

33 

MAGNETIC 

FIELD{ mAim) 

4.9 

3.7 

3.7 

3.7 

3.7 

31 

31 

31 

25 

22 

15 

74 

74 

74 

68 

68 

77 

62 

62 

62 

55 

49 

49 

92 

92 

99 

80 

continued on next page 
TABLE 2 -- Continued 

DESCRIPTOR 

(measurements taken every 10 meters) 

In field off lliili Road· 

On lliili Road· 

Farrington Highway near 

Manununu Street' 

Comparison points (see Table 4}. 

ELECTRIC 

FIELD (V/m) 

42 

44 

52 

52 

51 

47 

47 

44 

48 

40 

82 

50 

45 

.66 

MAGNETIC 

FIELD( mAim) 

74 

74 

74 

68 

62 

62 

60 

62 

62 

62 

As it became apparent during the study that overhead power lines shielded or 

reduced VLF electric fields beneath the lines, measurements were taken on the 

opposite side of the road from power lines whenever possible. To characterize this 

effect and establish maximum field values, two sets of measurements were made 

along traverses running perpendicular to power lines immediately outside the southern 

and western boundary fences of the transmitter facility (see Figures 3 and 4). Results 

of these traverse measurements are given in Figure 5. Both magnetic and electric 

fields were measured using hand-held instruments: the 5%-inch loop and oscilloscope 

18 
...-.. 

E 

- ~ E E -

> - - 0 

0 :;;::::: 

·;:: Q) 

u c:: 

O'l 

Q) ell 

w 2 

@)ij 

-

E ..- :::( E E 

> --- 0 

0 :;;::::: 

·c Q) 

u c:: 

O'l 

Q) ell 

w 2 

®mill 

100 

90 

80 

70 

60 

50 

40 

30 

20 

10 

0 10 20 

APANA TRAVERSE 

30 40 50 60 70 80 90 100 110m 

Distance from Power Line (meters) 

ILl ILl TRAVERSE 

80,---------------------------------------~ 

70 

60 

50 

40 

30 

20~~~--~--~~~~,~--~--~--~~--~--~--~ 

0 10 20 40 60 80 100 120 140 160 180 200m 

Distance from Power Line (meters) 

Figure 5. VLF Measurement Traversing Power Lines 

19 
and an EFS-1 meter. In the upper plot, "APANA TRAVERSE," power lines are at both 

0 and 10 meters; in the lower plot there was only one power line at 0 meters. It was 

found that VLF electric fields beyond the power lines in an open area could be 4 times 

greater than fields directly beneath the lines. This implies that other VLF electric field 

measurements made under power lines may be 4 times less than electric fields in 

adjacent open areas. It is known that houses also shield VLF electric fields reducing 

fields inside residences (see reference [2]). The VLF magnetic field was not as 

strongly affected by the power lines as was the electric field. 

To identify the source of field readings more clearly, the Navy, in cooperation with 

EPA, reduced the VLF transmitter power to 50 percent its normal value at scheduled 

times. The consistent drop in instrument field strength reading observed at these 

times in Table 3 confirmed that the source of the field was the VLF antenna. Note 

that field strength is proportional to the square root of the source power, so that a 0.5 

reduction in power implies a 0.707 reduction in field. 

TABLE 3. VLF MEASUREMENTS DURING REDUCTION OF POWER 

Measurement Location Field Strength Field Strength Ratio 

System at Normal Power at Half Power 

·~~·--~. 

IFI EFS-1 In Field Off 82 V/m 53 V/m .65 

lliili Road 

Whip and Digital On lliili Road 50 V/m 35 V/m .7 

Voltmeter 

continued on next page 

20 
TABLE 3 -- Continued 

Measurement Location Field Strength Field Strength Ratio 

System at Normal Power at Half Power 

Whip and On lliili Road 45 V/m 31 V/m 0.69 

Oscilloscope 

Whip and Farrington Highway 0.66 V/m .49 V/m .74 

Oscilloscope Near Manunu nu 

Street 

Histograms and smoothed data distribution plots for the VLF data are shown in 

Figures 6 and 7. The distributions are bimodal, which reflects two measurement 

populations: those at relatively low levels far away from the Navy site and a separate 

population of measurements at higher levels close to the site (see Section 3.2 ELF 

Results for explanation of plots). 

02o 

020 

ffi 0.15 a. 

-1.0 -{).2 06 1.4 2.2 

logE(V/m) 

Figure 6. VLF Electric Field Histogram 

and Smoothed Data 

21 

0,3 

a: 

cJj 0.2 

~ 

§ 

~ 0.1 

3.0 

log H(mA/m} 

Figure 7. VLF Magnetic Field 

Histogram and Smoothed Data 
3.1.2 LF Results 

Low-frequency fields were relatively weak and difficult to detect. The LF 

(146.1 kHz} waveform could be observed superimposed on the top of the oscilloscop1 

VLF waveform only when the LF response was greater than about one tenth the VLF 

response. A value is only reported for LF electric and magnetic fields where the LF 

response could be clearly read. The results are listed in Table 4 and shown on the 

map in Figure 8. Measured LF electric fields varied from 0.05 to 0.5 V/m. LF 

magnetic fields were measured at only two sites; both readings were 0.9 mAim. 

TABLE 4. LF RESULTS 

DESCRIPTOR 

Punanaula Street and Kaneaki Street 

Lualualei Homestead Road from Mailiilii Road 

going east 

(measurements taken every 0.2 mile) 

Farrington Highway 

starting at Makaha Valley Road going south 

(measurements taken every 0.5 mile) 

Three values at north end and three values 

at south end of Farrington Highway 

22 

ELECTRIC 

FIELD (V/m) 

.2 

.5 

.5 

.5 

.5 

.1 

.05 

.1 

.1 

.1 

.1 

MAGNETIC 

FIELD (mAim) 

.9 

.9 
Pacific 

Ocean 

N 

1.0 MILE 

OJ -~50.5~~ I;; ght J.R. Cfere U•edwiftlp ermi$.$ion. cop)111 

Figure 8 · LF Results 

23 
The limited measurement data presented here do not allow an accurate estimate 

of the maximum LF field strength at the site boundary. However, these results are 

compatible with a maximum LF electric field value at the site boundary of 1.24 V/m 

reported by the Navy in 1982 [3]. 

A histogram and smoothed data distribution plot for the LF electric data are 

shown in Figure 9. No histogram is possible for the magnetic field data, since there 

were only two sites and both had the same reading. 

0.5 

OA 

~ m 

a: & 0.3 

~ § 0.2- n. 0 ; 

8: i 

0.1 

-1.0 -0.8 -0.6 -0.4 -0.2 0.0 

log E(V/m) 

Figure 9. LF Electric Field Histogram and 

Smoothed Data 

24 
3.1.3 HF Results 

The large number of HF (3 to 30 MHz) antennas and possible operating 

frequencies precluded a study of all HF operating conditions. To estimate maximum 

field strengths outside the Lualualei facility due to HF operations, tests were performed 

near two antennas close to the northern boundary of the site. Measurements were 

made along Lualualei Homestead Road near a rhombic type antenna operating at 

8.077 MHz and near an inverted cone type antenna operating at 13.523 MHz. These 

antennas were operated in coordination with the Navy at the maximum of 1 0 kW of 

power and at typical operating frequencies. The results are listed in Table 5 and 

shown in Figure 10. The maximum magnetic field measured was 22 mA/m and the 

maximum electric field measured was 8.8 V/m. These were due to operation of the 

inverted cone antenna. 

TABLE 5. HF RESULTS 

DESCRIPTOR 

Lualualei Homestead Road 

going east along road 

starting from center of rhombic mainbeam 

(measurements taken every 5 meters) 

25 

ELECTRIC 

FIELD (V/m) 

1.9 

1.7 

1.5 

1.8 

2.3 

2.7 

MAGNETIC 

FIELD (mA/m) 

6.2 

6.4 

7 

6.6 

5.9 

5.9 

continued on next page 
TABLE 5 -- Continued 

DESCRIPTOR 

Lualualei Homestead Road 

in front of inverted cone antenna 

Puhawai Road and Lualualei Homestead 

ELECTRIC 

FIELD (V/m) 

2.7 

3.2 

3.2 

2.7 

2.5 

2.2 

2 

1.9 

2 

2 

7.1 

8.8 

MAGNETIC 

FIELD (mAim) 

6.4 

6.6 

6.6 

6.4 

6.1 

5.8 

5.4 

5.2 

4.8 

4.4 

20 

22 

The plot in Figure 11 shows the variation in electric and magnetic fields in front 

of the rhombic antenna. As expected, electric fields near ground are at a maximum at 

locations somewhat off the main beam axis [4]. Histograms and smoothed data 

distribution plots for the HF data are shown in Figures i 2 and 13. The distribution is 

bimodal because data from measurements near the inverted cone and rhombic 

antennas have been combined. 

26 
2.0 VIm 4.8 mAim 

2.0 V/m 5.4 m/Vm 

2.5 VIm 6.1 mAim 

3.2 VIm 6.6 mAim 

2.7 VIm 6.4 mAim 

2.3 V/m 5.9 mAim 

1.5 VIm 7.0 mAim 

1 .9 VIm 6.2 mAim 

2.0 V/m 4.4 mAim 

1.9 VIm 5.2 mAim 

2.2 VIm 5.8 mAim 

2.7 VIm 6.4 mAim 

3.2 V/m 6.6 mAim 

2.7 VIm 5.9 mAim 

1 .B VIm 6.6 mAim 

lnvened 

Cone 

0 400 800 FEET 

~~~--~~ 

Figure 1 o. HF results along Lualualei Homestead Rd. 

27 
10 

9 

8 

7 -

E 

--~ 6 .§ E > ........... -0 5 

0 +::; 

·;::: Q) 

- c 

(,.) 0> 4 Q) ro 

iii ::E 

3 

®~mil ;::::;: 

2 

1 

0 

0 10 20 30 40 50 60 70 80 m 

Distance along Lualualei Homestead Road (meters) 

Figure 11. Variation in Electric and Magnetic Fields In Front of Rhombic Antenna 

28 
ne 

~ 0.6 

Hi 0.4 0.. 

~ 0.3 fa:: 02 g 

!£ 0.1 

QO 0,4 0.8 1.2 

log E(V/m) 

Figure 12. HF Electric Field Histogram 

and Smoothed Data 

3.2 ELF Results 

0.6 

cr: 

~ 0.4 

~ 

~ 0.2 

[ 

06 0.8 1.0 1.2 1.4 1.6 

log H(mA/m) 

Figure 13. HF Magnetic Field 

Histogram and Smoothed Data 

ELF electric and magnetic fields were measured at residential street 

intersections that had numerous power distribution lines. Eleven measurement sites 

were selected (Fig. 3). Generally, each intersection was probed for a maximum field 

reading. In some cases, measurements were made at different corners of an 

intersection or at the middle of a block. Measurements taken in this way should 

sample the upper limits of fields due to power distribution lines in residential areas. 

The map in Figure 14 and the list in Table 6 show the results. ELF electric field 

strength values varied from 3.4 to 30 volts/meter (V/m) and magnetic field flux density 

varied from 0.5 to 15 milligauss (mG) or 40 to 1200 milliamps/meter (mAim}. 

29 
Pacific 

Ocean 

N 

0 0.5 

~~~5iiiiiii!~:. htJ.R. Clere Usedwt 'th permission, copyng 

i.O MILE 

Figure 14 · ELF Results 

30 
TABLE 6. ELF RESULTS 

ELECTRIC MAGNETIC 

INTERSECTION FIELD (V/m) FIELD (mG) 

Farrington Highway and Nanakapona 

School 17 10 

Auyong Homestead Road and Holomalia 

Street 30 .8 

Hakimo Road at end of pavement 3.4 .5 

Hakimo Road and Paakea Road 21 4.8 

0.2 miles from end of lliili Road 8.5 i 

Hookele Street and Ehu Street 4 4 

Maliona Street and Farrington Highway 5.2 2.5 

Kulaaupunl Street and Maliona Street 14 1.7 

Mill Street and Lualualei Homestead Road 18 5 

Mill Street and McArthur Street 25 1.3 

Farrington Highway and Kaupuni Street 4.1 15 

Histograms and smoothed data distribution plots for the ELF data are shown ln 

Figures 15 and 16. In order to avoid highly skewed distributions, the logarithm base 

10 of each data value in Table 6 has been calculated before entering the data into a 

statistical distribution plotting program. In addition, the units for the magnetic field 

31 
have been converted from milligauss to milliamps per meter by multiplying by 80 

before taking the logarithm. Interpreting these distributions is illustrated as follows. 

The histogram bar plot for the ELF electric field shows that most of the log of 

measurement values fall between 1.2 and 1.4 or, by taking the antilog (1 ax), most of 

the values fall between 15.8 and 25.1 volts per meter. The proportion per bar for this 

bar is about 0.37, meaning that 37% of the maximum electric field values measured at 

selected intersections are between 15.8 and 25.1 V/m. As another example, the 

smoothed distribution plot for the ELF magnetic field shows a peak in the log of the 

magnetic field distribution at about 2.2 or, taking the antilog, at 158 milliamps per 

meter or 2.0 milligauss. Thus, the most probable maximum magnetic field measured 

in selected residential intersections is 2.0 mG. 

0.4 

~ 0.3 a: 

w 

0.. 

~ 02 

li: 

!? @ 0.1 

D.. 

0.4 0.8 1.2 1.6 

log E(V/m) 

Figure 15. ELF Electric Field 

Histogram and Smoothed Data 

32 

ti: 

a§ 0.4 

~ 0.(3 

6 0.2 

i= l5 0.1 ll. 

0 

if t5 2.5 3.5 4.5 

log H(mA/m} 

Figure 16. ELF Magnetic Field 

Histogram and Smoothed Data 
3.3 Discussion 

This report presents results from a measurement survey intended to identify 

maximum electric and magnetic field levels in residential areas near Naval radio 

transmitters at Lualualei. The object was to gain some understanding of field levels in 

the community rather than conduct a detailed exposure assessment. The survey is 

thus considered exploratory for that reason, as well as for the following considerations. 

The equipment used was portable and somewhat limited. Measurement sites were 

not chosen .based on statistical or epidemiological considerations, but, rather, were 

chosen based on engineering judgment--the primary objective being to find the 

maximum field in publicly accessible areas out of doors. Finally, even though almost 

all the measurements were made in residential areas (housing, although sparse, 

surrounds the Navy site where readings were taken along roads and traversing power 

lines) the sites chosen for each frequency band are at different locations, which could 

result in misleading comparisons between data sets for the different bands. 

Only in the VLF band are the measurement data adequate to infer a range of 

field strength in the area. However, the VLF data do not allow prediction of exposure 

at any particular location. If this information were required, the next logical step would 

be to define numerical models of the VLF tower system and compare the results of 

numerical electromagnetic computer calculations to the measurement data. A 

confirmed model could then be used for field prediction. 

33 
4. CONCLUSIONS AND RECOMMENDATIONS 

This report documents the results of magnetic and electric field measurements 

made during the last week of November 1990 in the Waianae area of Oahu, Hawaii. 

The maximum electric and magnetic fields measured outside of the Navy site 

boundary in each frequency band are shown in Table 7. The range of VLF fields 

measured was 0.15 to 82 V/m and 2.5 to 99 mAim. The lower levels of fields at ELF, 

LF, and HF can not be inferred from the measurement data. 

TABLE 7. MAXIMUM FIELDS MEASURED DURING STUDY 

Frequency 

ELF 

VLF 

LF 

HF 

Electric 

Field (V/m) 

30 

82 

.5 

8.8 

Magnetic 

Field {mA/m) 

1200 (15 mG) 

99 

.9 

22 

If further efforts to quantify exposures in the area are directed, several activities 

could be initiated. These could include computer modeling of field sources, 

modulation measurements, ELF exposure measurements using generally accepted 

protocols, long-term monitoring of HF exposures, measurements of contact currents, 

and measurements indoors. However, such efforts could be expensive and may add 

only a marginal amount of additional information on field levels in the Lualualei area. 

34 
REFERENCES 

1. Mantiply, Edwin D. An Automated TEM Cell Calibration System. U.S. 

Environmental Protection Agency, EPA 520/1-84-024, October 1984. 

2. Smith, AA, "Attenuation of Electric and Magnetic Fields by Buildings," IEEE 

Transaction on E!ectromagentic Compatibility, EMC-20(3), August 1978. 

3. Personnel Radhaz (Radiation Hazard} Measurements at RTF Lualualei; Final 

Report. Department of the Navy, Naval Communication Area Master Station, 

Eastern Pacific, Wahiawa, Hawaii 96786-3050, October 1982. 

4. Mantiply, Edwin D., Hankin, Norbert N. Radiofrequency Radiation Survey in the 

McFarland, California Area. U.S. Environmental Protection Agency, EPA/520/6-

89/022, September 1989. 

35 
APPENDIX 

CALIBRATION DATA 

36 
IFI EFS-1 1 059-E 

Correction Factors 

Full Scale (V/m) 

Frequency {MHz} 3.00 10.0 30.0 J.QQ_ 

.0234 1.042 .988 1.046 .964 

.1461 .984 .952 .980 .909 

8.077 .890 .870 .865 .825 

13.523 .880 .860 .859 .825 

IFI EFS-1 1 060-E 

Correction Factors 

Full Scale (V /m) 

Frequency (MHz) 3.00 10.0 30.0 _j_Q_Q_ 

.0234 1.087 1.067 1.082 1.039 

.1461 .992 .988 .969 .952 

8.077 .909 .909 .887 .860 

13.523 .887 .889 .865 .860 

37 
~ 

"'C 

~ ...... 

t.. 

0 

-C.) 

ro 

~ 

!: 

0 

...... 

m 

$... 

~ 0 

u 

80 

60 

40 

20 

0 

-10 

0.01 0. 1 1.0 !0 

Frequency In Kilohertz 

• measured conversion factors found in TEM cell 

Conversion Factors for Picotesla Te:-::::1s 

:i\Iodel 94605-1 Loop .t\_Tlten...11a 

38 

100 
b2. 

BAND I 

.t!> .IG .11 .1a .19 .20 .21 .az .2:3 .24 .zs .2s .27 .ze .2s .;;o.m 

.so .11"1 ,68 .72 .76 .80 ,84 ,88 ,92 .96 1,00 1.04 1.08 1.12 !,15 

lD 50 

0 

-

~ 'i v 

~ u 1.10 

£ 

1.20 

I I 

I I 

I l 

L30 lAO 1.50 1.60 

~ 48~~~~~~~~~-+~~~+4~~ z 

z 

IA.I 

~ 44 

<C( 

a. 

g H-1-1-l--f-..j-..4 

2.6 

I I I I 

I I I I 

:f=t==t l 

I tt~r.o 4-

1.70 1.80 1.90 2.10 2.20 2.25 

3.8 

8.4 

a.o a.5 9.0 9.5 ta.o 10.5 1 1.0 11.5 12.0 12.5 13,0 13.5 14.0 14.5 1s.o 15.5 ts.o 16.5 

}2. 

17.0 18.0 19.0 20.0 21.0 22.0 23.0 24.0 25.0 26.0 27.0 28.0 29.0 30.0 31.0 32.0 

FREQUENCY- MC/S 

CALIBRATED BY' FOR S E S 92200-3 LOOP ANTENNA 

--------~~----------- DATE: SERIAL NO.------

us ~~~·1~ CHART 4- CORRECTION FACTORS, REMOTE LOOP ANTENNA 

NOTES: e antenna factors used for HF measurements 

39