NTIA Report 91-282 

Tabulations of Propagation Data 

Over Irregular Terrain in the 

75- to 8400-MHz Frequency Range 

Part V: Virginia 

George A. Hufford 

Francis K. Steele 

U.S. DEPARTMENT OF COMMERCE 

Robert A. Mosbacher, Secretary 

Janice Obuchowski, Assistant Secretary

for Communications and Information 

December 1991 

CONTENTS 

Page 

1. INTRODUCTION ...................................................................................................... 1 

2. MEASUREMENT PROGRAM AND EQUIPMENT................................................ 2 

 2.1. Transmitting Equipment ............................................................................ 7 

 2.2. Receiving Equipment................................................................................... 7 

3. MEASUREMENT PROCEDURES........................................................................... 8 

4. ACKNOWLEDGEMENTS ........................................................................................ 8 

5. REFERENCES........................................................................................................... 9 

6. DATA TABULATIONS............................................................................................. 9 

Appendix: SITE COORDINATES .................................................................................. 294 

iii 
LIST OF FIGURES

Page 

Figure 1. A view from the transmitter site T7................................................................. 3 

Figure 2. A map of the measurement region showing the 7 transmitter sites.............. 4 

Figure 3. A map of the measurement region showing the transmitter site

T1 and its associated receiver sites.................................................................. 5 

Figure 4. A map of the measurement region showing most of the 283 

 propagation paths.............................................................................................. 6 

LIST OF TABLES 

Page 

Table 1. Receiver Site Schedule...................................................................................... 2 

Table 2. Transmitter Characteristics ............................................................................. 7 

Table 3. Receiver Characteristics ................................................................................... 7 

iv 
TABULATIONS OF PROPAGATION DATA OVER 

IRREGULAR TERRAIN IN THE 75- TO 8400-MHz 

FREQUENCY RANGE 

Part V: Virginia 

G. A. Hufford and F. K. Steele∗

This is a supplementary fifth part to a series of reports containing tabulations and graphs of transmission loss data resulting from propagation 

experiments which have emphasized the UHF frequency band. The first four 

reports described data taken in various regions of Colorado. The present 

report concerns measurements taken at about the same time in the Piedmont 

region of Virginia and North Carolina. Data are presented for 283 paths 

varying in length from 0.5 to 120 km. 

Keywords: elevated antennas; irregular terrain; radio propagation; UHF propagation data 

1. INTRODUCTION 

The purpose of this report is to present tabulations of transmission loss data obtained 

in radio propagation experiments carried out over the rolling, grassy, wooded terrain in the 

Piedmont region of Virginia and North Carolina. Path lengths varied from 0.5 to 120 km, 

and frequencies from 76 to 8400 MHz. 

The data presented here were obtained as part of an extensive effort to study propagation in terrestrial environments. The first measurements of this program were in the 

VHF band and were reported by Johnson, et al. (1967a, 1967b, and 1967c). They were 

made in the plains and mountains of Colorado, and in the rolling hills of northern Ohio. 

A subsequent set of measurements emphasized the UHF band. A series of reports by 

McQuate, et al. (1968a, 1968b, 1970, and 1971) described such measurements made in 

Colorado under various environmental conditions. A companion set of measurements were 

made near Lynchburg, Virginia, and it is this set that is reported here. 

Some of these data were previously summarized in earlier reports by Barsis, et al. 

(1969) and by Longley and Reasoner (1970), but this is the first time the individual data 

 

∗

 The authors are with the Institute for Telecommunication Sciences, National Telecommunications and Information Administration, U.S. Department of Commerce, Boulder, 

Colorado 80303. 
have been published. It is hoped that in this form they will be helpful in studies of radio 

propagation and will make useful additions to collections of propagation data. 

Basic transmission losses are tabulated with frequencies, antenna heights, antenna 

gains, path lengths, terrain profiles, and brief comments pertinent to vegetation and structures along the paths. 

2. MEASUREMENT PROGRAM AND EQUIPMENT 

The region under study is a rural one with low, rolling hills. Much of it is farmed, but 

there are occasional groves of mostly loblolly pines and a few oak or hickory trees. Since

much of the data were collected during the winter, fields were usually bare and deciduous 

trees had no leaves. Figure 1 shows a typical view; the photograph was taken from ground 

height at the transmitter site T7. It pictures a barren field with only low structures and

low vegetation out to a distant horizon. 

In the general plan for the measurements there were 7 frequencies spaced by about an 

octave, fairly high antennas at both terminals, and a large number of paths. The paths 

were specified by 7 different transmitter sites to each of which were assigned about 50

receiver sites having one of 8 nominal distances and one of the two conditions “open” 

or “concealed” as indicated in Table 1 below. An “open” site has a clear, unobstructed 

foreground in the direction of the other terminal, while a “concealed” site is either within

a grove of trees or immediately in front of an obstruction such as a tree or building. The 

concealed receiver sites were usually associated with a companion open site that was within

100 m. In such cases, of course, the two propagation paths were almost identical. 

Table 1. Receiver Site Schedule 

------------------------------------------------------------------------- 

Nominal path length Open sites Concealed sites 

0.5 km 2 – 

3 2 –

5 4 –

10 6 –

20 6 4

50 6 4

80 6 4

120 4 2

The transmitter site T2 was on top of Piney Mountain and surrounded by the pine 

trees that cover that small, 349-m high, knoll. It was, therefore, a “concealed” site. The 

other transmitter sites were all “open.” They were either in parking lots or in open fields. 

Figures 2, 3, and 4 are maps of the region showing various aspects of how the terminal sites 

are placed. The maps are outline maps showing county boundaries and a small portion 

of the boundary between Virginia and North Carolina. Figure 2 shows the 7 transmitter 

sites; Figure 3 shows the transmitter site T1 together with its associated receiver sites; and 

Figure 4 illustrates how completely the paths criss-cross the region by plotting all paths 

longer than the 3-km set. 

2
3
4
5
6
2.1. Transmitting Equipment. 

Transmitting equipment was carried in a van with a trailer-mounted collapsible 11-m 

antenna tower. The van carried power generators, signal generators, frequency counters,

and power meters, all of which were used to control the radiated frequency and power. Continuous wave, horizontally polarized signals were radiated from antennas located 8–15 m

above ground. Table 2 shows the frequencies used and the major transmitter characteristics, including antenna parameters and output powers. Antenna gains are those supplied

by the manufacturers.

Table 2. Transmitter Characteristics

Max Xmtr 

Frequency, MHz Antenna type Gain, dBi power, dBm

75.98 Yagi 9.2 49.0

172.98 Yagi 9.2 49.0

409.25 Corner reflector 12.2 47.0

950.0 Parabolic dish 18.9 49.0

2180 Parabolic dish 26.2 40.0

4820 Parabolic dish 33.3 40.0

8395 Parabolic dish 37.9 40.0

2.2. Receiving Equipment 

To make the process more efficient, the receivers were duplicated and carried in two

separate vans. A “short range receiver van” (van 1) was used primarily for reception on 

short to mid-range paths, while a “long range receiving van” (van 2) was used on the 

longer paths. The difference between the two was that the short range van used smaller 

antennas for the higher frequencies.

Each van had a trailer-mounted, collapsible, 16-m tower and a full complement of 

antennas. The vehicles carried power generators, receivers to cover the entire frequency 

range, attenuators, strip chart recorders for displaying signal amplitude, and signal generators for calibration. Table 3 shows the major receiver characteristics, the antenna gains

and the receiver sensitivities expressed here as the largest basic transmission loss that 

could be measured. 

Table 3. Receiver Characteristics 

Antenna gains and maximum measurable losses 

Frequency Van 1 Van 2 

gain, dBi max Lb, dB gain, dBi max Lb, dB 

75.98 9.2 181 9.2 180

172.98 9.2 184 9.2 183

409.25 12.2 188 12.2 188

950.0 13.2 181 18.9 186

2180 12.5 181 26.2 192

4820 17.4 188 33.3 207

8395 16.2 202 37.9 223

7
The antennas were identical to those used at the transmitter, except that the short

range receiver van did not use parabolic dishes. Instead, another Yagi antenna was used

at 950 MHz and horns were used at the three higher frequencies. Antenna heights were

10–15 m above ground, except for a few “low antenna” measurements that were made 2 m 

above ground. 

3. MEASUREMENT PROCEDURES 

The transmitter and receiver sites were first selected by a fairly random process from 

topographic maps, and then checked for suitability and accessibility. Each transmitter site

would be occupied for about 6 weeks so that the installation could be relatively permanent 

with, for example, guyed antennas. Receiver sites were of a more temporary nature and 

were seldom visited for more than a day. 

When a receiver site was occupied, the receiver power was turned on and the antenna

tower was erected and sometimes guyed for stability. Antenna pointing azimuths were 

initially determined from maps and then more closely optimized by small changes in the

orientation at both terminals. After warm-up, the receivers were calibrated by injection 

of a known signal from a signal generator. Receiver outputs were recorded on strip chart

recorders which were calibrated simultaneously with the receivers in 5 dB increments. The 

final determination of each received signal level was a median value from about 10 minutes

of strip chart recordings. On some occasions, wind shook the antennas thus causing

fluctuations in the received power level; then additional time was required for stabilization.

The measured received signal levels were converted to basic transmission loss Lb using 

the standard formula . 

 Lb = Wt – Wr + Gt + Gr – Lt – Lr

where Wt is the transmitter power in dBm, Wr is the received signal level in dBm, Gt and Gr

are the antenna gains in dBi, and Lt and Lr are the line losses in dB. 

4. ACKNOWLEDGEMENTS 

The authors want to thank present and former colleagues for helpful discussions. In

addition, gratitude is due to personnel at General Electric in Lynchburg, Va., for their 

good efforts under undoubtedly trying conditions. Finally special thanks are due to the

Office of Spectrum Management at NTIA for supporting this effort. 

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5. REFERENCES 

Barsis, A. P., M. E. Johnson, and M. J. Miles (1969), Analysis of propagation measurements

over irregular terrain in the 76- to 9200-MHz range, ESSA Tech. Report ERL 114–

ITS 82 (NTIS Order No. AD 699 072). 

Johnson, M. E., M. J. Miles, P. L. McQuate, and A. P. Barsis (1967a), Tabulations of 

VHF propagation data obtained over irregular terrain at 20, 50, and 100 MHz, ESSA 

Tech. Report IER 38–ITSA 38 (NTIS Order No. AD 655 854). 

Johnson, M. E., M. J. Miles, P. L. McQuate, and A. P. Barsis (1967b), Tabulations of VHF 

propagation data obtained over irregular terrain at 20, 50, and 100 MHz. Part II: 

Colorado mountain data, ESSA Tech. Report IER 38–ITSA 38–2 (NTIS Order No.

AD 662 713). 

Johnson, M. E., M. J. Miles, P. L. McQuate, and A. P. Barsis (1967c), Tabulations of VHF 

propagation data obtained over irregular terrain at 20, 50, and 100 MHz. Part III:

Ohio data, ESSA Tech. Report IER 38–ITSA 38–3 (NTIS Order No. AD 667 530). 

Longley, A. G., and R. K. Reasoner (1970), Comparison of propagation measurements with

predicted values in the 20 to 10,000 MHz range, ESSA Tech. Report ERL 148–ITS 

97 (NTIS Order No. AD 703 579). 

McQuate, P. L., J. M. Harman, and A. P. Barsis (1968a), Tabulations of propagation data

over irregular terrain in the 230- to 9200-MHz frequency range. Part I: Gunbarrel 

Hill receiver site, ESSA Tech. Report ERL 65–ITS 58 (NTIS Order No. AD 671 271). 

McQuate, P. L., J. M. Harman, M. E. Johnson, and A. P. Barsis (1968b), Tabulations

of propagation data over irregular terrain in the 230- to 9200-MHz frequency range.

Part II: Fritz Peak receiver site, ESSA Tech. Report ERL 65–ITS 58–2 (NTIS Order 

No. AD 689 708). 

McQuate, P. L., J. M. Harman, M. E. McClanahan, and A. P. Barsis (1970), Tabulations 

of propagation data over irregular terrain in the 230- to 9200-MHz frequency range.

Part III: North Table Mountain—Golden, ESSA Tech. Report ERL 65–ITS 58–3

(NTIS Order No. AD 715 753). 

McQuate, P. L., J. M. Harman, and M. E. McClanahan (1971), Tabulations of propagation

data over irregular terrain in the 230- to 9200-MHz frequency range. Part IV: 

Receiver site in grove of trees, OT/TRER 19 (NTIS Order No. COM 75–10839 / AS). 

6. DATA TABULATIONS 

Data tabulations are presented on pages 11 through 293. Each page corresponds to

one distinct path as identified in the upper left hand corner. The identification is similar to

that used in the previous reports of this series. Its three parts are (1) the coded transmitter

site, (2) the nominal length of the path, and (3) the receiver site, coded sequentially in the

clockwise direction. For example, T3–10–R4 is the path that has the fourth receiver site

on the 10-km circle around the transmitter site T3. These identifications are also used to

9
define the order of presentation in the following pages, for the same three parts provide a 

natural categorical ordering. Pairs of open and concealed sites are considered to have the

same paths and their data are incorporated into one page. 

The top half of each page is devoted to the path profile. These were read by hand 

from 1/62,500 scale maps. They are plotted against a curved earth with an effective

radius based on a surface refractivity of 305 N-units, which is an average value for this 

area. Transmitter sites are plotted on the left and receiver sites on the right. Note also 

that the profiles for each circle of constant nominal radius are plotted using fixed, standard 

scales, both vertically and horizontally. 

The actual radio data are in the table in the bottom half of the page. In a sequence of 

columns appear frequencies, then antenna heights, and values of basic transmission loss.

While antenna heights were fairly constant, there was enough variability to make it seem

necessary to include their values in each table. The tables are of variable length because

a receiver site may have had more than one set of measurements made, and each set is

displayed in a separate row. Note that each row of losses is accompanied by the date of 

the measurements and by an indication of which van took them. 

Several of the attempted measurements could not be made because the loss was too 

large and the received signal level was below the receiver noise level. In such cases, the 

situation has been identified in these tables with the word “noise” in place of a measured

loss. Then the actual loss should have been comparable to, or greater than, the maximum 

measurable losses given in Table 3. On the other hand, if an entry in these tables is empty, 

then the corresponding measurement was not even attempted. This may have been either 

because it was not part of the planned measurements, or because there was a failure in

some of the associated equipment. 

10