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=@$=@#METHODS FOR PREDICTING INTERFERENCE FROM RESPONSE STATION
TRANSMITTERS AND TO RESPONSE STATION HUBS AND FOR SUPPLYING
DATA ON RESPONSE STATION SYSTEMS.
This document sets out the methodology to be used in carrying out three requirements with respect
to response stations used as part of twoway cellularized MDS and ITFS systems. It details the
methods for conducting interference studies from response stations to other systems; it details the
methods for calculating interference protection for response station hubs; and it defines a file format
to be used in submitting data in response station hub applications. It also describes the propagation
analysis techniques to be used in these studies.
3#]\ P4QP#Four Major Steps for Response Station Interference Analysis#XP\ P5QXP#
In carrying out the studies of interference from response station transmitters, the aggregate power
of the interfering signals to be expected from the response station transmitters shall be determined
using a process comprising four major steps, as described below. First, a grid of points shall be
defined that is statistically representative of the distribution of transmitters to be expected within the
response service area, and the elevations to be associated with each of them shall be determined.
Second, any regions and any classes of response stations to be used shall be defined. Third, the
appropriate transmitter configuration to be used in each interference study shall be determined.
Fourth, the equivalent power of each of the representative transmitters shall be determined and used
in the various required interference studies. The parameters used in the studies shall be provided in
a prescribed electronic form as described later in this document.
fDefining Grid of Points for Analysis
Since it is impossible to know a priori where response stations will be located, a grid of points is used
to represent statistically, in a relatively small number of locations, the potentially much larger number
of response stations that are likely to be installed in the areas surrounding each of the points. Once
defined, the same grid of points shall be used by all parties conducting interference analyses involving
the subject response station system.
Defining the representative grid of points to use in all the interference studies required in Rule
Sections 21.909 and 74.939 begins by geographically defining the response service area (RSA) of the
response station hub (RSH). This may be done using either a list of coordinates or a radius from the
response station hub location. When coordinates are used, straight lines shall interconnect one
location with the next in the order given in the list, and the last location described shall be connected
to the first location by a straight line. When a radius from the response station hub location is used,
the value shall be expressed in miles, with any fractional part expressed as a decimal value to three
places. The boundaries described are administrative and serve to circumscribe the area in which
response station transmitters may be located.The characteristics of any sectors in the RSH receiving antenna also must be described in two ways:
geographically, so as to limit the locations from which response stations will transmit to each sector,
and electrically, by providing data on the electrical field response of the antenna pattern in each
sector. Sectors may overlap one another geographically. The geographic boundaries of a sector shall
be defined using either a list of coordinates or a list of bearings. Electrical field response data shall
be relative to the direction of maximum response of the sector antenna and shall be provided every
one (1) degree completely around the antenna. Both azimuth and elevation field patterns shall be
supplied for each polarization to be used with a given antenna type. The geographic orientation of
each sector to the nearest degree and the polarization in each sector also shall be specified. When
response stations share channels or subchannels by transmitting simultaneously on them, the
maximum number of response stations that will be permitted to transmit simultaneously within each
sector must be specified.
The RSA may be subdivided into regions to allow different characteristics to be used for response
stations in different portions of the RSA. (For details on regions and their use, see the section below
on Defining Regions and Classes for Analysis.) Any regions to be used when analyzing interference
must also be described in a manner similar to that used to describe the RSA itself. Analysis of the
regions involves use of one or more classes of response station characteristics. For each such class,
a combination must be specified of the maximum antenna height, the maximum equivalent isotropic
radiated power (EIRP), and the worst case antenna pattern that will be used in practice in installations
of response stations associated with that class within the respective regions. (For details on classes
and their use, see the section below on Defining Regions and Classes for Analysis.) When response
stations share channels or subchannels by transmitting simultaneously on them, the maximum number
of response stations associated with each class that will be permitted to transmit simultaneously within
each region and each sector must be specified.
To define the grid of points, a line is first established surrounding the RSA, following the shape of
the RSA boundary, mile outside the RSA, and never more than mile from the RSA boundary
at any point. This is termed the analysis line and will be used in determining that an adequate
number of grid points representing transmitters is being used in the interference analyses. A starting
point is defined on the analysis line due north (true) of the response station hub. A series of analysis
points is then spaced along the analysis line with the starting point being one of those points. The
analysis points must occur with a spacing no greater than every mile along the analysis line or every
5degrees (as seen from the response station hub), whichever yields the largest number of analysis
points. When an RSA has a noncircular shape, the choice of distance along the analysis line or angle
from the response station hub must be made for each portion of the line so as to maximize the number
of analysis points in that portion. The analysis points are to be described by their geographic
coordinates. (The results of this method are that, for a circular RSA, a minimum of 72 analysis points
will be used, and that, for portions of the analysis line of any RSA more than 5.73 miles from the
response station hub, the distance method will be used.)
Next, the grid of points is defined within the RSA to statistically represent the response stations. The
grid uses uniform, square spacing of the points, as measured in integer seconds of latitude and
longitude, with the first square surrounding the RSH and with its points equidistant from it. The lines
connecting the points on one side of any grid square point true north, east, south, or west. The gridis defined so as to include all points within or on the boundary of the RSA, with the exceptions noted
below. The result is that the grid can be defined by only two values " the coordinates of the hub and
the separation between adjacent grid points in seconds " combined with the description of the RSA
boundary.
Any points falling at locations at which it would be physically impossible to install a response station
(such as in the middle of a lake, but not the middle of a forest) are removed from the grid. The points
of the grid so removed are to be described by their geographic coordinates.
The grid of points is then divided into two groups. The division is to be done using a checkerboard
pattern so that alternating points along the eastwest and northsouth axes belong to opposite groups
and points along any diagonal line belong to the same group.
The combination of the grid of points within the RSA and the points on the analysis line is next used
to determine that the number of grid points is truly representative of a uniform distribution of
response station transmitters within the RSA. This is done by conducting a power flux density
analysis from each grid point within the RSA to each point on the analysis line. For this analysis, a
single response station should be assumed to be located at each grid point, that response station
having the combined worst case antenna pattern without regard to polarization of all response station
classes assigned to that grid point and the maximum EIRP of any response station class assigned to
that grid point. (For details on the method for determining the combined worst case antenna pattern,
see the section below on Defining Regions and Classes for Analysis.) The response station antennas
all should be oriented toward the response station hub.
The analysis of grid point adequacy should be done using free space path loss over flat earth only and
should not include the effects of terrain in the calculation of received signal levels. At each point on
the analysis line, the power flux density from all grid points in each group of the checkerboard pattern
should be aggregated. This is done by converting power received from each assumed transmitter
from dBW/m2 to W/m2, summing the power in W/m2 from all transmitters in each group, and then
converting the sum back to dBW/m2.
After the aggregated power flux density from each of the two groups has been calculated, the
received power flux densities from the two groups are compared at each of the points on the analysis
line. The power flux densities from the two groups must be within 3dB of one another at each of
the points on the analysis line. In addition, there must be no closer spacing of grid points that allows
a difference of greater than 3dB between the groups. If the power flux densities of both groups are
within 3 dB at every analysis point, a sufficient number of grid points is included for use in further
analyses. If they are not within 3 dB at every analysis point, a larger number of grid points (i.e.,
closer spacing of grid points) must be used so that the 3dB criterion is met.
In cases in which sectorized response station hubs are used, a further test is required to assure that
an adequate number of grid points is used. In addition to meeting the requirements of the preceding
paragraph, each sector must contain a number of grid points equal to or greater than the distance
from the hub to the furthest point in the sector, expressed in miles, divided by two, with a minimum
of five grid points per sector. Should an insufficient number of grid points fall within any sector aftermeeting the 3 dB criterion, the point spacing for the entire RSA must be decreased until this
additional requirement is satisfied.
Once the geographic locations of the grid points are determined, the elevations to be attributed to
each must be decided. This is done by creating a geographic square uniformly spaced around each
grid point having a width and a height equal to the spacing between grid points and oriented in the
same directions as the lines between grid points used to lay out the grid structure. Each such square
is then examined with respect to all of the data points of the U.S. Geological Survey (USGS) 3second database falling within the square to find the elevation of the highest such data point,
expressed in feet. That elevation is ascribed to the associated grid point and shall be used for the
elevation of that grid point in all further and future analyses of the response station system.
Heading 2#XP\ P6QXP#dDefining Regions and Classes for Analysis Heading 2
#XP\ P7QXP#To provide flexibility in system design, regions may optionally be created within response service
areas. Regions may be of arbitrary size, shape, and location. The territory within a region must be
contiguous. Regions within a single RSA may not overlap one another. Within regions, response
stations are apt to be randomly distributed and for analysis purposes are to be assumed to be
uniformly distributed. Regions are to be defined by their boundaries in the same manner as are
response service areas. (For details on describing boundaries, see the section above on Defining Grid
of Points for Analysis.)
Within each region, at least one class of response station with defined characteristics must be
specified to match the interference predicted to be caused with the types of installations to be made.
The classes are to be used in interference analyses and to provide limitations on the installations that
may be made in the related region. The characteristics of each such class of response stations shall
include the maximum height above ground level (AGL) for antennas, the maximum equivalent
isotropic radiated power (EIRP), and the combined worstcase antenna radiation pattern ! for each
polarization when both are used ! for all response stations of that class to be installed. When
response stations share a channel by transmitting simultaneously (see section below on Determining
Transmitter Configuration), for each class of response stations within each region, the maximum
number of such response stations that may transmit simultaneously on any channel or subchannel
shall be specified.
The combined worstcase antenna azimuth radiation pattern is required to be specified collectively
for all of the classes of response stations located at each grid point (in the procedure above, in the
section on Defining Grid of Points for Analysis, for confirming that the required number of grid points
is specified) and individually for each of the classes defined for each region of the RSA. In the case
of the collective pattern used to determine adequacy of the number of grid points, if both
polarizations are used in the system, the horizontally and verticallypolarized azimuth patterns of
each antenna should be treated as deriving from separate antennas and should be combined with one
another and with the patterns from all the other antennas at that grid point. In the cases of the
individual patterns for each class used for interference analyses, if both polarizations are used in the
system, the horizontally and verticallypolarized combined worstcase azimuth patterns should be
determined separately for all classes defined. Similarly, the crosspolarized worstcase patterns
should be determined for each polarization.These combined worstcase patterns are derived by setting the maximum forward signal power of all
antenna types to be used within the class or classes to the same value and then using the highest level
of radiation in each direction from any of the antennas as the value in that direction for the combined
antenna pattern. The same method is used to determine both plane and crosspolarized patterns,
which are used separately in interference analyses. The combined worstcase plane and crosspolarized patterns for each class will be used in all of the interference studies and are not to be
exceeded in actual installations of response stations within a class to which the pattern applies.
Heading 2#XP\ P8QXP#dDetermining System Configuration Heading 2
#XP\ P9QXP#Several factors in the configuration of a system determine whether or not transmitters located at
specific grid points could cause interference to particular neighboring systems. In order to simplify
the study of interference to those neighbors, the system configuration is taken into account so as to
reduce the number of calculations required by eliminating the study of interference from specific grid
points when possible. The main factor that determines whether to eliminate certain grid points from
consideration is terrain blockage.
When grid points are completely blocked from lineofsight to any part of a neighboring system, they
can be eliminated from the aggregation of power used in calculating interference to that system. To
determine whether to eliminate a grid point for this reason, a shadow study can be conducted from
each grid point in the direction of the neighboring system. Separate studies can be conducted for
classes of response stations that have different maximum elevations above ground. If there is no area
within the protected service area or at any of the registered receiving locations of the neighboring
system to which a particular class of station at a grid point has lineofsight, it can be eliminated from
the calculations that determine the power of interfering signals at the neighbors location.
Alternatively, lack of lineofsight can be evaluated from each class at each grid point to each location
analyzed within the neighboring system (see section below on Calculating Aggregated Power from
Transmitters), and grid points can be eliminated on a locationbylocation basis, if that process is
more easily implemented.
There are two ways in which a large number of response stations can share channels: They can take
turns using the channels so that only one transmitter will be turned on at any particular instant on each
channel or subchannel being received by a separate receiver in the system, or they can transmit at
the same time and use special filtering techniques at the receiver to separate the signals they are
sending simultaneously to that receiver. These two cases will result in different levels of power being
radiated into neighboring systems, and therefore they must be analyzed slightly differently.
In the case of response stations that take turns using a channel or subchannel, the grid point and class
of station that produces the worst case of interference to each analyzed location in the neighboring
system must be determined for each group of response stations that share a channel (e.g., within a
response station hub receiving antenna sector). In this case, the interfering signal source can be
treated as a single transmitter occupying the full bandwidth of the channel or subchannels used from
that location and having a power level equal to the aggregate of the power transmitted on all of the
subchannels, if subchannels are used.
In the case of response stations that simultaneously share a channel or subchannel, the grid point and
class of station that produces the worst case of interference to each analyzed location in theneighboring system must be determined for each group of response stations that share a channel (e.g.,
within a response station hub receiving antenna sector). In this case, the interfering signal source can
be treated as a single grid point at which are located all of the simultaneously operating transmitters,
occupying the full bandwidth of the channel or subchannels used from that location, and having a
power level equal to the aggregate of the power transmitted by all of the response stations operating
simultaneously on all of the subchannels, if subchannels are used.
In cases of sharedchannel operation in which the number of simultaneously operating response
stations of a class is limited by a region that crosses sector boundaries, the number of such response
stations considered within some sectors may be limited so that the total included in the analysis in all
sectors does not exceed the total permitted for the region. The objective in analyzing these cases is
to find the worst case situation with regard to the maximum number of simultaneously operating
transmitters, assigning them collectively to the locations at which they cause the most interference
to each location analyzed within neighboring systems, while respecting the limits imposed on the
number of such transmitters by sector and by region. A statement describing in detail the process or
algorithm followed in selecting the number and classes of response stations analyzed at each grid
point shall be appended to the application and distributed as a standard ASCII text file along with the
data file described below in the section on the File Format.
An example of the case just described of sharedchannel operation with the number of simultaneously
operating transmitters limited both by region and by sector is one in which a region comprises an
annular ring that stretches from half the radius to the full radius of a circular RSA. The region has
a limit of 200 simultaneously operating transmitters of a particular class, and each of 20 sectors is
limited to 20 simultaneously operating transmitters. If the worst case interference from each sector
were caused by the subject class and all were used in analyzing interference to a neighboring system,
the result would be the use of 400 such response stations (20 x 20) in the analysis, while the region
is limited to 200. Consequently, the 10 regions (10 x 20 meets the limit of 200) causing the most
interference to the neighbor would be selected, and, in the other 10 sectors, the classes of station
causing the second largest amount of interference to the neighbor would be selected for use in the
analysis. In choosing the secondary interfering response station classes, the same type of limitations
would have to be observed. The process for making these selections based on the appropriate
limitations would have to be followed for each analyzed point in the neighboring system.
Heading 2#XP\ P:QXP#dCalculating Aggregated Power from Transmitters Heading 2
#XP\ P;QXP#The final major step in calculating interference from response station transmitters is the calculation
of the equivalent isotropic radiated power (EIRP) to be attributed to each of the selected grid points
in the various interference studies so as to be representative of the number of response stations that
are expected to be in operation simultaneously within the RSA. When analyzing systems in which
the response stations take turns using a channel or subchannels, this means, for each location
analyzed in the system to be protected, selecting the grid point and class of station within each sector
that radiates the strongest signal to that location and aggregating the power from all such selected
grid points and classes, using the maximum EIRP (for all subchannels taken together), the maximum
antenna height, and the worst case antenna pattern for a single station of that class at each selected
grid point. For systems in which response stations simultaneously share the channel or subchannels
to each receiver at each hub, substantially the same analysis is performed. The difference is that the
maximum number of simultaneously operating response stations within each sector is placed at eachselected grid point, in turn. The maximum EIRP (for all subchannels taken together) for each
regional class at each grid point or additional point, expressed in dBW, is converted to Watts. The
power is then multiplied by the number of simultaneously operating transmitters in the regional class
assigned to that grid point or additional point, and the resulting power in Watts is converted back to
dBW. When the number of simultaneously operating transmitters within a sector in the class and at
the grid point that causes the most signal to be propagated to a location in the neighboring system
does not equal the number of simultaneously operating transmitters permitted in that sector, the grid
point and class of station that cause the next largest amount of signal to be so propagated shall be
used to account for the remaining number of simultaneously operating transmitters permitted in the
sector, and so on as necessary. At each location analyzed within the neighboring system, the power
received from the selected grid points within each sector is aggregated through conversion from dBW
to Watts, addition of power levels, and conversion back to dBW. In each case, the values so
calculated are the aggregated powers of all the simultaneously operating response station transmitters
sharing the same channel(s) or subchannel(s), from all sectors, for use as the undesired signal levels
in interference analyses .In a system using both polarizations, the response stations represented by
each grid point are to be assumed to use the polarization of the response station hub antenna sector
in which they are located. The appropriate horizontal or vertical combined worstcase antenna
pattern is to be used in interference studies depending upon the polarization of the sector in which
each grid point is located. In a system using only one polarization, the effect of antenna sectors can
be ignored and the choice between horizontal and vertical polarization patterns made identically for
all grid points.
Finally, the aggregate power of each active regional class at each active grid point is used in
conducting the required interference studies described in the relevant Rules. For example, to
determine that the -73dBW/m2 limitation is met, a field strength contour is calculated by first
calculating a matrix of field strengths from each regional class at each grid point in the RSA into the
region of the PSA or other boundary to be protected using the terrainbased propagation analysis tool
specified below (i.e., free space path loss plus reflection and multiple diffractions " see section below
on Propagation Analysis Tool). The matrix represents an array of locations on a square grid
separated by a short distance (no more than 1 mile). Once the protected area matrix is calculated
from signals originating at each regional class at each grid point or additional point, the matrices are
summed by first converting from dBW/m2 to W/m2, adding the field strength values from all regional
classes at all grid points at each matrix point, and converting from W/m2 back to dBW/m2. The
summed matrix is then used to route a protection contour by interpolating between matrix points.
The contour so determined should not cross the boundary under consideration. When response
stations partially or completely share channels, subchannels or superchannels with booster and/or
primary stations within the same system, the interference contributions of these stations must be
added to those of the response stations in order to determine the overall interference impact of the
system and its conformance with applicable interference protection criteria.
Similar methods should be used in conducting the other interference studies required in this section.
These include the desiredtoundesired (D/U) signal ratio studies for cochannel and adjacent channel
interference. In all of these studies, the analysis should use the aggregate power of each regional class
at each grid point or additional point, the worst case plane or crosspolarized antenna pattern, as
appropriate, for each regional class, with the antennas at each grid point aimed toward the response
station hub, and the maximum antenna height above ground specified for each regional class at eachgrid point or additional point.
#]\ P<QP#Protection to Response Station Hubs#XP\ P=QXP#
Protection to response station hubs is required from two types of neighboring systems: those applied
for or licensed prior to the licensing of the subject response station hub and those applied for or
licensed subsequent to the licensing of the subject response station hub. In cases in which the
neighboring system was licensed first, the protection to be provided to the response station hub after
any modifications of the neighboring system shall be no less than that provided prior to the
modifications. In cases in which the neighboring system is licensed later, the protection to be
provided to the response station hub after construction of the neighboring system shall be such as not
to degrade the noise floor of hub receivers by more that 1 dB for cochannel signals and 45 dB for
adjacent channel signals. The methods to be used to determine the amount of protection provided
or the amount of degradation follow.
For purposes of interference protection calculations, an applicant for a response station hub shall
specify the geographic coordinates of the hub location and, for each sector, (1) the height of the
antenna above ground (AGL) and above mean sea level (AMSL), (2) the hub receiving antenna
pattern (both in azimuth and elevation, both co and crosspolarized in the main vertical lobe), (3) the
hub receiving antenna gain in the main lobe (in dBi), (4) the azimuth of the main lobe, (5) any
mechanical tilt to be utilitized, and (6) the polarization of the receiving antenna.
The level of interference caused to a response station hub by either an existing or a new MDS or
ITFS station shall be independently determined for each sector. In making such a determination, the
power from all sources (main, booster, and response stations) related to a particular primary license
of an individual licensee shall be aggregated to yield an effective power flux density of the interfering
signal(s). The resulting summation can then be used for comparisons between old and new values
when existing stations are modified or for comparison against the specified receiver degradation
threshold for new stations that are proposed.
In calculating the effective power flux density value, the effective isotropic radiated power (EIRP)
radiated in the direction of the response station hub from each main, booster, and/or response station
(as represented by the selected grid points described earlier in the section Four Major Steps for
Response Station Interference Analysis) of the neighboring system shall first be determined. The
power arriving at the response station hub shall be analyzed using the propagation analysis tool
described in the following section on that subject. The aggregation of power from all related sources
shall take account of the angular displacement of each particular source from the peak of the main
lobe of the receiving antenna and the relative polarization of each interfering signal source.
To determine the effective power flux density, the following formula shall be used:
0
<0dd
<ZNPFD sub EFF = 10log sub 10 ``stack {n#sum#1} 10 sup {{ISi+G sub REL i}over 10}Z
xx#(((-2700<A(1)Where:` ` PFDEFF=Effective Power Flux Density (dBW/m2)
` ` n=Number of Interfering Signal Sources (units)
` ` ISi=Interfering Signal Power Flux Density of ith Source (dBW/m2)
` ` GRELi = Relative Gain of Hub Sector in Direction of ith Source (dB)
` ` (includes antenna discrimination & polarization effects)
For neighboring systems licensed first, it is necessary to ascertain that the value of the effective power
flux density after a modification, as predicted for each response station hub antenna sector, does not
exceed the value predicted for the same sector prior to the modification. For new neighboring
systems, an additional step is required to ascertain that the predicted value of the effective power flux
density does not exceed the allowed threshold values for both cochannel and adjacent channel
signals.
To calculate the relationship of the effective power flux density to the threshold values for cochannel
and adjacent channel signals, the level of the noise floor of the hub receiver first must be figured. It
is given by the formula:
0
<dd
<pdP sub THERMAL = 10 log ``LEFT [` k ` ` sup 5 `/ sub 9 ` (T-32) + 273 ` ` ` BW RIGHT ] p
',ii16;qq@(2)
Where:` ` PTHERMAL= Noise Power from Thermal Sources (dBW)
` ` k= Boltzmanns Constant (1.380662 x 10é23)
` ` T= Noise Temperature (degrees Fahrenheit)
` ` BW= Bandwidth (Hz)
With a typical noise temperature of 63 deg. F and a bandwidth of 6 MHz, Equation 2 yields a thermal
noise power of 136.2 dBW. The equivalent total power flux density of the thermal noise power plus
the effective power flux density of the interfering signal(s) is given by:
0:<
dd:<PFD sub \EQUIV` = ` 10log sub 10
`LEFT (`10 sup {{ PFD sub EFF} over 10} +
10 sup {{P sub THERMAL - L sub c + NF + G sub ANT}over 10}`RIGHT )
.((38= (3)
Where:` ` PFDEQUIV = Equivalent Total Power Flux Density (dBW / m2 )
` ` LC = Cable Losses (dB)
` ` NF = Noise Figure of First Amplifier (dB)
` ` GANT = Antenna Gain (dBi)
Compliance with the limits for cochannel and adjacent channel interference from new stations to
response station hubs can be determined by first calculating the equivalent total power flux density
with the effective power flux density of the interference set to zero and then recomputing with thetrue effective power flux density. The two values found should not differ by more than 1dB for cochannel interference nor by more than 45dB for adjacent channel interference.
Heading 1#]\ P>QP# rPropagation Model Heading 1
#XP\ P?QXP#When analyzing interference from response stations to other systems and from other systems to
response station hubs, a propagation model shall be used that takes into account the effects of terrain
and certain other factors. The model is derived from basic calculations described in NTIS Technical
Note 101.X0ÍX0ÍF3'Letter#XN\ P@XP##C\ PAQP# Í Transmission Loss Prediction for Tropospheric Communication Circuits, Technical Note 101, NTIS Access
Number AD 687820, National Technical Information Service, US Department of Commerce, Springfield, VA.F It is intended as a tool for analysis of wide area coverage of microwave transmissions,
and it is available built into commercial propagation analysis software packages that are widely used
by the MDS/ITFS industry for coverage and interference prediction.3'Letter#XN\ PBXP##C\ PCQP# Í An example of such a software implementation is the Free Space + RMD) method included in some products
of EDX Engineering, Inc.
In the model described, two loss terms are computed " the free space path loss based solely on
distance and the excess path loss (XPL) that derives from terrain obstacles and other elements in the
environment. Among the inputs required for some implementations of the model are location and
time variability factors. Other factors for such items as clutter and foliage losses can be considered
by some software versions, but they will not be used in analyzing the systems considered herein.
The excess path loss portion of the calculation considers several conditions that impact signal
propagation. These include whether the path is line of sight for the direct ray, whether there is 0.6
first Fresnel zone clearance, or whether the path is totally obstructed. When the path is unobstructed,
a single ground reflection is added to the direct ray to determine path loss. When the first Fresnel
zone is partially obstructed, an additional loss up to 6 dB is included by the model. When the path
is totally obstructed, the path loss is calculated using the EpsteinPeterson methodFootnote Ref#A\ PDP##Footnote Ref##XP\ PEQXP#C3'Letter#XN\ PFXP# Í#C\ PGQP# J. Epstein and D.W. Peterson. An experimental study of wave propagation at 850 Mc., Proc. IRE, vol.41,
no. 5, pp. 595611, May, 1953.#XN\ PHXP#C that considers the
diffraction losses over successive terrain obstacles. In this case, each obstacle is treated separately,
with the preceding obstacle (or the transmitter, in the first instance) considered to be the transmitter
and the succeeding obstacle (or the receiver, in the last instance) considered to be the receiver.
Some software implementations of the methods described herein may provide for setting parameters
for both location and time variability in terms of the percentage of the locations or of the time that
signals meet or exceed studied levels. For purposes of analyzing the interference from response
stations and to response station hubs, both the location and the time variability factors shall be set to
50 percent in all cases. When available as a parameter, the confidence level shall be set to 50percent.
In conducting analyses of interference from response stations, the minimum acceptable signal
threshold shall be set to the noise floor for the bandwidth involved, as calculated per Equation 2
above. Thus for a 6 MHz channel, the minimum signal level considered would be 136.2 dBW or 106.2 dBm. As a result of this setting, when the desired signal falls below this level, the D/U ratio
from any interfering signal source will be ignored. These studies shall be conducted based exclusively
upon the levels of the desired and undesired signals without the addition of thermal noise.
Heading 2#XP\ PIQXP#dPropagation Model Outline Heading 2
#XP\ PJQXP#For the purposes of these Rules, the propagation model has three basic elements that affect the
predicted field strength at the receiver:
1) LineofSight (LOS) mode, using basic tworay theory with constraints
2) Nonlineofsight (NLOS) mode, using multiple wedge diffraction
3) Partial first Fresnel zone obstruction losses applicable to either mode
The LOS and NLOS modes are mutually exclusive " a given path between a transmitter and a
receiver is either LOS or not. The fundamental decision as to whether a path is LOS is based on the
path geometry. That decision is described in the next subsection, which also defines the LOS mode
for the model.
Heading 2#XP\ PKQXP#dLineofSight (LOS) Mode Heading 2
#XP\ PLQXP#The determination of whether a path between a transmitter and a receiver is LOS is made by
comparing the depression angle of the path between the transmitter and receiver with the depression
angle to each terrain elevation point along the path. The depression angle from transmitter to receiver
is computed using an equation of the form:
i
3ddi
3YXMital sub {t-r} = {h sub r - h sub t}over d sub r - {d sub r over {2 a} }Y
&..+0566:?D (4)
where:
tr is the depression angle relative to horizontal from the transmitter to the receiver in radians
ht is the elevation of the transmit antenna center of radiation above mean sea level in meters
hr is the elevation of the receive antenna center of radiation above mean sea level in meters
dr is the great circle distance from the transmitter to the receiver in meters
a is the effective earth radius in meters taking into account atmospheric refractivity
The atmospheric refractivity is usually called the K factor. A typical value of K is 1.333, and using
the actual earth radius of 6340 kilometers, a equals 8451 kilometers, or 8,451,000 meters. For the
purpose of these Rules, K = 1.333 shall be used.
Using an equation of the same form, the depression angle from the transmitter to any terrain elevation
point can be found as:0<0dd<[Oital sub {t-p} = {{h sub p - h sub t}over d sub p} - {d sub p over {2 a }}[
ss###({{-2++7<A(5)
where:
tp is the depression angle relative to horizontal for the ray between the transmitter and the
point on the terrain profile
hp is the elevation of the terrain point above mean sea level in meters
dp is the great circle path distance from the transmitter to the point on the terrain path in
meters
ht and a are as defined above following Equation (4).
The variable tp is calculated at every point along the path between the transmitter and the receiver
and compared to tr. If the condition tp > tr is true at any point, then the path is considered NLOS
and the model formulations in the subsection on NonLineofSight (NLOS) Mode below are used.
If tp tr is true at every point, then the transmitterreceiver path is LOS and the formulations in
this subsection apply.
For LOS paths, the field strength at the receiver is calculated as the vector combination of a directly
received ray and a single reflected ray. This calculation is presented next. If the geometry is such that
a terrain elevation point along the path between the transmitter and receiver extends into the 0.6 first
Fresnel zone, then an additional loss ranging from 0 to 6dB is included for partial Fresnel zone
obstruction. This is discussed in a subsequent subsection.
Heading 3#]\ PMQP#dTwoRay Field Strength at the Receiver Using a Single Ground Reflection Heading 3
#XP\ PNQXP#For an LOS path, the field at the receiver consists of the directly received ray from the transmitter
and a number of other rays received from a variety of reflecting and scattering sources. For low
antenna heights (on either the transmit or receive end of the path) the field at the receiver is
dominated by the direct ray and a single reflected ray which intersects the ground near the transmitter
or receiver, whichever is nearer to the ground. The heightgain function in which a field at the
antenna increases as the height of the antenna above ground increases is a direct result of the direct
and ground reflection rays adding vectorially so that the magnitude of the resultant manifests this
effect. The heightgain function is modeled here by considering the actual ground reflected ray and
the direct ray in vector addition. The magnitude of the direct ray is given by:
=dd=QEE sub r = 1 over d sub r sqrt {{P sub t G sub t }over {4 ! }}Q\\+
\\+05dd:? D(6)
where Er is the field strength at the receive point, PT is the transmitter power delivered to the
terminals of the transmit antenna, GT is the transmit antenna gain in the direction of the receive point
(or the ray departure direction), is the plane wave free space impedance (377 ohms), and dr is the
path distance from the transmitter to the receive point in kilometers.
Written in dB terms, this reduces to:
9tdd9t8,E sub r = 76.92-20.0 log (d sub r) + P sub T8ߵ'
dBV/m,VV16;^^@ (7)
In Equation (7), PT is effective radiated power (ERPd) in dBW. The magnitude and phase of the
groundreflected ray are found by first calculating the complex reflection coefficient as follows:
ddXR``=``R sub s ```gߛ
tt$$$||).,,38=44B (8)
where Rs is the smooth surface reflection coefficient and g is the surface roughness attenuation factor
(a scalar quantity).
For parallel and perpendicular polarizations, respectively, the smooth surface reflection coefficients
are:
4
dd4
R sub {s } = { =sin sub 0 - {sqrt{ =-cos sup 2 sub 0}}} over {=sin sub 0 + {sqrt{ =-cos sup 2 sub 0}}}
parallel polarizationgg6;@o o E(9)
4
dd4
R sub {s Y } = {sin sub 0 - {sqrt{ = -cos sup 2 sub 0}}} over {sin sub 0 + {sqrt{ =-cos sup 2 sub 0}}}
perpendicular polarization;@o o E(10)
where 0 is the angle of incidence and = is the complex permittivity given by:
gdd
g4(= = = sub 1 - j60 % sub 1 4߱
&oo+05ww:?' ' D(11)
where =1 is the relative dielectric constant of the reflecting surface, %1 is the conductivity of the
reflecting surface in Siemens/m, and is the (free space) wavelength of the incident radiation. For
the case of ground reflection, verical polarization is parallel polarization and horizontal polarization
is perpendicular polarization.
For the model defined here, it is assumed that the local surface roughness is 0 (smooth surface) so
that the term g in Equation (8) is one. Also, values of %1 = 0.008 Siemens/meter and =1= 15 are
commonly used for ground constants and shall be employed unless specific values for the location
being studied are available.
Since the lengths of the reflected path and the direct path are essentially the same (differing by only
a few wavelengths or less), the amplitude of the two rays due to spatial attenuation (path length) is
assumed to be the same. The reflected ray, however, is multiplied by the reflection coefficient as
given above and then shifted (retarded) in phase as a result of the longer path length compared to the
direct ray. The vector addition of the two rays at the receiver is thus:
3dd
3XLE sub r ` = ` E sub d ` sin( 3 t)+E sub d ` R ` sin ( 3 t+ C )X
where:
Ed is the magnitude of the direct ray
3 is the carrier frequency in radians
R is the complex reflection coefficient given above
C is the phase delay of reflected ray in radians
The carrier term is usually suppressed so that the magnitude of Equation (12) becomes
i0<Wdd<`E sub r ``~=~ E sub d````1 + R ``e sup{i( C sub r + C )}~~~~~~~~~~~~~~~~~~~~~~#
~~~~~=~E sub d ` SQRT {(1+R ` ` cos ( varphi sub r + DELTA varphi ))^2+(R ` ` sin (varphi sub r + DELTA varphi))^2}i
,cc16;kk@ E##J(13)
where Cr is the phase angle of the reflection coefficient. The term C is found from the actual path
length difference in meters. For a tworay path geometry over a curved earth, the path length
difference is given by:0<dd<A5 r = {2h sub t ```h sub r}over d sub r A߾
22"',::16;(14)
where:
h#]\ POQP#'#XP\ PPQXP#t is the height of the transmit antenna above the reflecting plane in meters
h#]\ PQQP#'#XP\ PRQXP#r is the height of the receive antenna above the reflecting plane in meters
so that
0<dd<RF C = ` {2 ! r}over ~~~ (modulo ~2 !~ radians)R
&MM+05UU:(15)
The usual issue in using this approach is defining where the reflecting plane is for a complex terrain
profile between transmitter and receiver. The reflection point is found by evaluating the angle of
incidence and reflection at every terrain elevation point along the path. The angle of incidence at any
point along the path profile (the evaluation point) is found from simple geometry as follows:
0r<ddr<MA sub t ` ` = ` ` tan sup{-1}~ {[h sub t ` ` / ` ` d sub t]} M
` ` hh#(-pp2(16)
for the transmitter, and
0<dd<MA sub r ` ` = ` ` tan sup{-1}~ {[h sub r ` ` / ` ` d sub r]} M
DD %*LL/49TT>(17)
for the receiver. The terms ht, hr, dt, and dr are the transmit antenna height above the evaluation point,
the receive antenna height above the evaluation point, and the distances from the evaluation pointto
the transmitter and receiver, respectively. The evaluation point where t = ris considered the
reflection point. However, it is unlikely that these angles will ever be exactly equal. In such cases,
at the two adjacent evaluation points where the angles inflect (i.e. r becomes larger than t), the
reflection point is considered to exist along the profile segment defined by the adjacent points. The
exact reflection point is then found along this profile segment using linear interpolation since the
profile segment is by definition a linear slope. With the distance and elevation of the reflection point
established, the reflection angle of incidence 0 is found using an equation of the form of Equation
(16). This value of 0 is then used in Equation (9) or (10) to find the magnitude and phase of the
reflection coefficients.
The effect of the nearby ground reflection will be to reduce the amplitude of the directly received raybecause, in general, the two rays will add out of phase. The amplitude of the reflected ray will be
nearly equal to the direct ray because, at low reflection angles of incidence, R#]\ PSQP#t#XP\ PTQXP#1.0 for most practical
combinations of frequency, conductivity, and permittivity. For an antenna placed very near the
ground, the cancellation calculated through use of these formulas will be almost perfect, so that the
directly received (free space) ray will be reduced by 40 dB or more. It is unlikely, however, that such
a perfect cancellation will occur in the real world. It is therefore appropriate to put some reasonable
limits on the change in amplitude of the directlyreceived ray that can be caused by a reflection.
Based on measurement and theoretical data, the limits placed on change in the free space amplitude
due to reflections are 25 dB and + 6 dB.
Thus based on the preceding discussion, the path loss or attenuation term Areflection can be written as:
{0<Wdd<ital A sub reflection `` = `` -20 ` log````1 + R ` TIMES `e sup{i( C sub r + C)}``~~~~~~~~~~~~~~~~~~~~~#
~~~~~~~~ = ` ` -20`log`` sqrt{{(1+R ` cos( C sub r + C ))sup 2 + (R ` sin( C sub r + C ))sup 2}}{
SS1 (18)
with the limits that 6.0 dB Areflection 25.0 dB.
Heading 3#]\ PUQP#dAttenuation Due to Partial Obstruction of the Fresnel Zone Heading 3
#XP\ PVQXP#When a path is LOS but terrain obstacles are close to obstructing the path, additional attenuation will
occur which cannot be accounted for using the ray approach just discussed. The failure of the ray
approach to account for attenuation due to a near miss of obstacles on the path can be overcome
to some extent by including a loss term in the LOS formulation which is based on the extent to which
an obstacle penetrates the first Fresnel zone. From diffraction theory, when the ray just grazes an
obstacle, the field on the other side is reduced by 6 dB (half the wavefront is obstructed). When the
clearance between the obstacle and the ray path is 0.6 of the first Fresnel zone, the change in the field
strength at the receiver is 0 dB, and with additional clearance a field strength increase of 6 dB can
occur owing to the inphase contribution from the ray diffracted from the obstacle. For additional
clearance, an oscillatory pattern in the field strength occurs.
In the model described, if the ray path clears intervening obstacles by at least 0.6 of the first Fresnel
zone, then no adjustment to the receiver field will occur. For the case when an obstacle extends into
the 0.6 first Fresnel zone, a loss factor ranging from 0 to 6 dB is applied based on a linear proportion
of how much of the 0.6 First Fresnel zone is penetrated. This Fresnel zone path loss or attenuation
term can be written as:
0< dd<wkA sub Fresnel ` `=` ` 6.0` ` LEFT (1.0 - {{C sub obs `(d sub p`)} over {R sub {FR}` (d sub p`)}} RIGHT)~dBw
$\\).3dd8=(19)
where:
Cobs(dp) is the height difference in meters between the ray path and the terrain elevation at
distance dp along the pathRFR(dp) is the 0.6 first Fresnel zone radius at distance dp along the path
The values Cobs(dp) and RFR(dp) are calculated taking into account the effective earth radius using the
K factor. The 0.6 first Fresnel zone radius is given by
0<dd<R sub FR ``(d sub p `)`=`0.6``LEFT [ `549.367 `` sqrt {{ d sub p ``(d sub r ` - ` d sub p ` )} over {f d sub r}}`` right ]~~~meters
,RR16;(20)
where f is the frequency in MHz and all distances are in kilometers.
The use of the partial Fresnel zone obstruction loss from 0 dB at 0.6 clearance to 6 dB at grazing also
provides a smooth transition into the NLOS mode in which knifeedge diffraction loss just below
grazing will start at 6 dB and increase for steeper ray bending angles to receiving locations in the
shadowed region. Note that this attenuation factor is found only for the terrain profile point that
extends farthest into the 0.6 first Fresnel zone, not for every profile point which extends into the 0.6
first Fresnel zone.
Heading 3#]\ PWQP#dSummary of Calculation of Field Strength at the Receiver Under LOS Conditions Heading 3
#XP\ PXQXP#All of the formulations for computing the field strength at the receiver under LOS conditions are now
in place. They can be summarized with the following simple equation:
0<dd<wXkE sub r `=`` 76.92``-``20`log``(d sub r``)`+``P sub T ` - ` A sub reflection ` - A sub Fresnel~~~~dB mu V/mw
mm16;(21)
where Areflection is the change due the reflection in dB from Equation (18), and A Fresnel is the partial
Fresnel zone obstruction loss from Equation (19). The term PT is the effective radiated power (ERPd)
in dBW in the direction of the receiver.
In terms of path loss between two antennas with gains of 0 dBi in the path direction, Equation (21)
can be written as:
0n<ddn<rXfL sub LOS `` = `` 32.45 `` + `` 20.0`log`f`+`20`log`d sub r`+`A sub reflection ` +` A sub Fresnel~~~dBr
\\16;(22)
Heading 2#XP\ PYQXP#NonLineofSight (NLOS) Mode Heading 2
#XP\ PZQXP#The mechanism for deciding when to use the LOS mode and when to use the NLOS mode is
described at the beginning of the subsection on LineofSight Mode above. When the model elects
to use the NLOS formulations to follow, it means that one or more terrain or other features obstructs
the ray path directly from the transmitter to the receiver. In this case, the free space field strength
is further reduced for the attenuation caused by the obstacles. For the model defined here, the
calculation of obstruction loss over an obstacle is done by assuming the obstacle is a perfect electrical
conductor rounded obstacle with a height equal to the elevation of the obstruction and a radius equalFigure 1Figure 1
~^method01.wpg
. ! Geometry for computing vħڐto 1 meter. Diffraction loss in this model is calculated assuming individual obstacles on the path can
be modeled as isolated rounded obstacles. The losses from multiple isolated obstacles are then
combined.
Heading 3#]\ P[QP#dDiffraction Loss Heading 3
#XP\ P\QXP#The loss over an individual rounded obstacle is primarily a function of the parameter v that is related
to the path clearance over the obstacle. The total diffraction loss, A(v,#), in dB, is the sum of three
parts " A(v,0), A(0,#), and U(v,#). The equations to calculate the total and the three parts are given
below:
A(v,#) = A(v,0) + A(0,#) + U(v,#)(-pp27 <xxA(23)
A(v,0) = 6.02 + 9.0v + 1.65v2 for 0.8 v 0pp27 <xxA(24)
A(v,0) = 6.02 + 9.11v + 1.27v2 for 0 v 2.4pp27 <xxA(25)
A(v,0) = 12.593 + 20log10 (v) for v > 2.4-pp27 <xxA(26)
A(v,0) = 6.02 + 5.556# + 3.148#2 + 0.256#3pp27 <xxA F(27)
U(v,#) = 11.45v# + 2.19(v#)2 0.206(v#)3 ĩ 6.02 for v# 3 <xxA F(28)
U(v,#) = 13.47v# + 1.058(v#)2 0.048(v#)3 ĩ 6.02 for 3 < v# 5 <xxA(29)
U(v,#) = 20v# 18.2 for v > 5(-pp27 <xxA F(30)
where the curvature factor is
0l
<ddl
<\XP# =`0.676``R sup {0.333} ` f sup {-0.1667}``sqrt{{d over {d sub 1``d sub 2}}}\
` ` hh#(-(31)
The obstacle radius R is in kilometers, and the frequency f is in MHz. The distance term d is the path
length from the transmitter (or preceding obstacle) to the receiver (or next obstacle), d1 is the distance
from the transmitter (or preceding obstacle) to the obstacle, and d2 is the distance from the obstacle
to the receiver (or next obstacle). When the radius is zero, the obstacle is a knife edge, and A(v,#) =
A(v,0).
The parameter v in the equations above takes into account the geometry of the path and can be
thought of as the bending angle of the radio path over the obstacle. It is computed as:
0)<
dd)<YMital v ` ` = ` ` SQRT {{2 d ` ` tan ( alpha ) ` ` tan ( beta )}over lambda }Y
//#(77-27??<A(32)
where d is the path length from the transmitter (or preceding obstacle) to the receiver (or next
obstacle), is the angle relative to a line from the transmitter (or preceding obstacle) to the receiver
(or next obstacle), and is the angle relative to a line from the receiver (or next obstacle) to the
transmitter (or preceding obstacle). The definitions of and are shown in Figure 1. For the
multiple obstacle case, obstacles are treated successively as transmitterobstaclereceiver triads to
construct the path geometry and bending angle v over each obstacle. The value of v is then used to
calculate the diffraction loss over each obstacle. The resulting obstacle losses are summed to arrive
at the total obstacle diffraction loss for the path.
Heading 3#]\ P]QP#dSummary of Calculation of Field Strength at the Receiver Under NLOS Conditions Heading 3
#XP\ P^QXP#The field strength at the receiver in the NLOS mode can then be written as:
0Z<5ddZ<YXME sub r``=`` 1`04.77`-`20`log`(d sub r)`+`P sub T`-`A sub diff~~~dB V/mY
,]]16
;ee@(33)
where all the terms have the same definitions as given in the preceding subsection and the term Adiff
is defined as:
0<dd<SGital A sub diff = SUM FROM {n = 1} TO {n sub obs} {A sub n (v,rho)~~dB}S
''"',//16;77@ E(34)
where A(v,#) is defined in Equation (23) and nobs is the number of obstructions in the path.
The corresponding path loss between antennas with 0 dBi gain in the path direction can be written
as:
A'ddAWXKL sub NLOS``=``32.45``+``20.0 log``f``+``20`log`d sub r``+``A sub diff~~~dBW7tt<A$!$!F(35)
Heading 1#]\ P_QP# Heading 1
#XP\ P`QXP#
#]\ PaQP#File Format#XP\ PbQXP#
To facilitate the exchange of data on twoway MDS and ITFS systems permissible under Parts 21
and 74, a file format is herein described for the submission of requisite technical data to be provided
to the Commission's copy contractor and to all parties which must be served with notice of the
applications and/or engineering studies. The media and basic formatting of that media are defined
by ISO/EIC Standards 9293.5 95291.6 and 95292.7.
The remainder of this document outlines the format of technical information regarding each Response
Service Area (RSA) to be submitted with each MDS/ITFS twoway application. The data shall
appear in a number of sections for the purpose of grouping similar items within the file. Data shallbe coded in an ASCIIformatted,&3'Letter#XN\ PcXP##C\ PdQP# Í ANSI X3.41986 (R1992), Coded Character Set " 7Bit American National Standard Code for Information
Interchange#XN\ PeXP#& commadelimited file. Carriage return (0Dh) and line feed (0Ah)
characters shall be placed at the end of each line in the file, as is normal when using standard text
editors. To help in identifying data, where file sections are formatted as tables, the first entry in each
row within a table shall be a sequence number indicating the position of the row within the table. To
the extent possible, the sequence number shall be representative of the type of data contained on the
row, such as the number of degrees of azimuth or elevation.A generic example of the required file
construction appears at the end of this section and may be used as a template for the submission of
data. As shown there, section titles shall appear on a separate line in square brackets [ ] and shall
be separated from the preceding sections and from the data within their own sections by a blank line.
Headers shall appear on the top line of the data contained within a section. Headers may contain data
and may also help with both human and machine readability.
Units of measure that are to be utilized for all information supplied in the file are:
Latitude ! Degrees, Minutes, Seconds (DD,MM,SS)
Longitude ! Degrees, Minutes, Seconds (DDD,MM,SS)
Azimuth or Bearing ! Degrees (to 1 decimal place)
Radius ! Miles (to 2 decimal places)
Ground Elevation ! Feet AMSL (to 0 decimal places)
Antenna Height ! Feet AGL (to 0 decimal places)
Antenna Tilt ! Degrees (to 1 decimal place)
Power (EIRP) ! dBW (to 2 decimal places)
Antenna Gain ! dBi (to 2 decimal places)
1. General Information
Section Title:` ` General Info
Entries:` ` File Number (Assigned by Commission)
` ` Licensee name
` ` City/State of hub location ` ` Coordinates of hub location
` ` Ground Elevation of hub location (feet)
` ` Call sign/file number of station being modified (if applicable)
` ` City/State of station being modified
2. Geographic Boundary Definitions ! Circular Areas Only
Section Title:` ` Circular Geographic Areas
Section Header:RSA Circular (0 or 1), Regions Circular (00 or RR, where RR = total # of
circular regions)
` ` Entries:00, RSA Center Latitude, RSA Center Longitude, RSA Radius (omit
entries other than leading 00 if RSA is noncircular)
` ` 01, Region 01 Center Latitude, Region 01 Center Longitude, Region 01
Radius
` ` 02, Region 02 Center Latitude, Region 02 Center Longitude, Region 02
Radius
` ` hh#(-:
` ` hh#(-:
` ` RR, Region RR Center Latitude, Region RR Center Longitude, Region RR
Radius
The geographic area of an RSA or region may be described by a circle having a defined center point
location and a radius. If the RSA is circular, then RSACircular= 1, otherwise 0.
If there are circular regions, then Regions Circular = the number of such regions, RR. Otherwise,
Regions Circular = 00.
3.Geographic Boundary Definitions ! NonCircular Areas
Section Title:` ` NonCircular Areas
Section Header:RSA NonCircular (0 or 1), Regions NonCircular (00 or NN, where NN =
total # of noncircular regions), # of points defining RSA (XXX), # of points
defining region RR+1 (AAA), 8, # of points defining region RR+NN (ZZZ)
Entries:` ` RSA Latitude (001), RSA Longitude (001), Region 01 Latitude (001), Region
01 Longitude (001), 8, Region NN Latitude (001), Region NN Longitude
(001)` ` RSA Latitude (002), RSA Longitude (002), Region 01 Latitude (002), Region
01 Longitude (002), 8, Region NN Latitude (002), Region NN Longitude
(002)
` ` hh#(-:
` ` hh#(-:
` ` RSA Latitude (XXX), RSA Longitude (XXX), Region 01 Latitude (AAA),
Region 01 Longitude (AAA), 8, Region NN Latitude (ZZZ), Region NN
Longitude (ZZZ)
The geographic descriptions of an RSA in the sections for Circular Areas Only (Section 2) and for
NonCircular Areas are mutually exclusive. One of them shall have the RSA indicator set to 1; the
other shall be set to 0. Any RSA data contained in the section with the RSA indicator set to 0 shall
be ignored.
Regions of both types, i.e., circular and noncircular, are permitted within a single RSA. Regions in
this noncircular section shall be numbered sequentially continuing from the last region number in the
circular section, i.e., from RR+1 to RR+NN, so that all regions have unique region numbers.
4.Hub Sectorization Data
Section Title:` ` Sectorization
Section Header:# of sectors within RSA (SS)
Entries:` ` Sector 01, Hub Receive Antenna Pattern #, Gain, Azimuth of Main Lobe,
Height AGL, Mechanical Beam Tilt, Polarization, Max Simultaneous
Transmitters
` ` Sector 02, Hub Receive Antenna Pattern #, Gain, Azimuth of Main Lobe,
Height AGL, Mechanical Beam Tilt, Polarization, Max Simultaneous
Transmitters
` ` hh#(-:
` ` hh#(-:
` ` Sector (SS), Hub Receive Antenna Pattern #, Gain, Azimuth of Main Lobe,
Height AGL, Mechanical Beam Tilt, Polarization, Max Simultaneous
Transmitters
Each sector is to be assigned a number beginning with the sector whose main lobe azimuth is pointing
due north or the closest to due north when proceeding in a clockwise direction from true north.
The receiving antenna pattern used in each sector is defined in the Antenna Pattern Data section, andthe association of each sector with a specific antenna pattern is made here. This pattern shall be used
in the calculation of potential interference to a hub from surrounding stations.
The geographic definition of each sector is found in the Sector Geographic Definitions section.
Mechanical beam tilt for each hub receiving antenna is specified in this section. Tilting the antenna
downward is defined using a positive number.
The polarization of each sector is defined as either horizontal or vertical.
The maximum number of transmitters that can operate simultaneously on the channel or any
subchannel within each sector is specified in this section.
5.Grid Point Definitions
Section Title:` ` Grid Points
Table Header:` ` # of grid points (MMMM)
Entries:` ` Point 0001: Latitude, Longitude, Elevation, Region # in which Located,
Bearing to Hub, Polarization (H, V, or B), Number of associated Class(es) of
Station(s), Class Designators
` ` Point 0002: Latitude, Longitude, Elevation, Region # in which Located,
Bearing to Hub, Polarization (H,V, or B), Number of associated Class(es) of
Station(s), Class Designators
` ` hh#(-:
` ` hh#(-:
` ` Point MMMM: Latitude, Longitude, Elevation, Region # in which Located,
Bearing to Hub, Polarization (H,V, or B), Number of associated Class(es) of
Station(s), Class Designators
The header specifies the total number of grid points (MMMM) defined in the Grid Point Definition
Table.
The location of each grid point is defined by latitude and longitude. The bearing from the grid point
to the hub is specified. The region in which the grid point is located is indicated using the region
number assigned in the sections above giving geographic boundary definitions. Grid points not
located in specifically defined regions shall be indicated as being in Region 00, which describes the
remainder of the RSA.
Polarization for each grid point must be specified as horizontal (H), vertical (V), or both (B). In areas
where sectors having opposite polarizations overlap, it may be desirable to have the flexibility to
utilize both polarizations. If so, grid points in these overlapping areas must be specified as B, bothpolarizations.
Each grid point must be assigned at least one class of station. Assignment of multiple classes to a
single grid point is also permitted.
6. Sector Geographic Definitions
Section Title:` ` Sector Definitions
Table Header:` ` # of sectors (SS), Bearings or Coordinates (B or C)
Entries:` ` Sector 01, Start Bearing, Stop Bearing
(Bearings)` ` Sector 02, Start Bearing, Stop Bearing
` ` hh#:
` ` Sector SS, Start Bearing, Stop Bearing
` ` hh#OR
Table Header:` ` ` # of sectors (SS), Bearings or Coordinates (B or C), # of Coordinates in sector 01
(CC1), # of Coordinates in Sector 02 (CC2), 8, # of Coordinates in sector SS
(CCC)
Entries:` ` Sector 01 Latitude (001), Sector 01 Longitude (001), Sector 02 Latitude
(001), Sector 02 Longitude (001), 8, Sector SS Latitude (001), Longitude
Sector SS (001)
` ` Sector 01 Latitude (002), Sector 01 Longitude (002), Sector 02 Latitude
(002), Sector 02 Longitude (002), 8, Sector SS Latitude (002), Sector SS
Longitude (002)
` ` hh#(:
` ` hh#(:
` ` Sector 01 Latitude (CC1), Sector 01 Longitude (CC1), Sector 02 Latitude
(CC2), Sector 02 Longitude (CC2), 8, Sector SS Latitude (CCC), Sector SS
Longitude (CCC)
Sector geographic boundaries can be described in either of two ways: (1) as straight lines radiating
out from the hub location at the specified bearings until they cross the outer boundary of the RSA,
or (2) as sets of coordinates between which straight boundary lines exist that describe closed
geographic areas. In either case, sectors may overlap, and, when they do, grid points in the overlap
areas must be analyzed as though they were included exclusively within each sector. When sets of
coordinates are used, the last coordinate pair shall be assumed to connect to the first such pair.
7.Response Station Class Data
Section Title:` ` Class Info
Table Header:` ` # of classes (CL)
Entries:` ` Class 1, Worst Case Ant Pattern #, Max Height, Max Power, Number ofRegions in Which Used, Region(s) in Which Used, Maximum Simultaneous
Number within Each Region
` ` Class 2, Worst Case Ant Pattern #, Max Height, Max Power, Region(s) in
Which Used, Maximum Simultaneous Number within Each Region
` ` hh#:
` ` hh#:
` ` Class CL, Worst Case Ant Pattern #, Max Height, Max Power, Region(s)
in Which Used, Maximum Simultaneous Number within Each Region
Classes are defined by the combination of the worst case antenna pattern, the maximum height above
ground level (AGL) at which the antennas may be mounted, and the maximum power (EIRP) they
may emit.
Associated with each class description is one or more pairs of values indicating the region numbers
in which the class is used and the maximum number of transmitters that may transmit simultaneously
on the channel or on each subchannel within each region. The two types of values alternate, and one
pair is present for each region in which the particular class is used. The regions shall be listed in
ascending numerical order.
8.Antenna Pattern Data (Hub Receive and Worst Case Response Transmit) 1ې|<DL! V #XN\ PfXP# 1
X` hp x (#%'0*,.8135@8: