Radiocommunications (Unacceptable Levels of Interference 2010-2025 MHz Band) Determination 2006 (Cth)
Radiocommunications (Unacceptable Levels of Interference — 2010‑2025 MHz Band) Determination 2006
Radiocommunications Act 1992
The AUSTRALIAN COMMUNICATIONS AND MEDIA AUTHORITY determines the following unacceptable levels of interference under subsection 145 (4) of the Radiocommunications Act 1992.
Dated 23 August 2006
Chris Chapman (signed) Chairman
Lyn Maddock (signed) Deputy Chair
Australian Communications and Media Authority
Contents
1Name of Determination 2
2Commencement 2
3Purpose 2
4Interpretation 3
5Group of transmitters 5
6Group of receivers 6
7Unacceptable level of interference 6
8Emission designator 7
Schedule 1Centre location and effective radius of a transmitter 8
Schedule 2Device boundaries 10
Part 1Device boundary of a transmitter or a group of transmitters 10
Part 2Device boundary criterion (2010‑2025 MHz) 11
Part 3Calculation of Propagation Loss 12
Schedule 3Average Ground Height and Transmitter Antenna Height 17
Schedule 4Overview of Propagation Loss (Modified extract from Rec ITU‑R P.526.8) 20
1 Name of Determination
This Determination is the Radiocommunications (Unacceptable Levels of Interference — 2010‑2025 MHz Band) Determination 2006.
2 Commencement
This Determination commences on the day after it is registered.
3 Purpose
This Determination sets out what is an unacceptable level of interference caused by a transmitter operating under a spectrum licence issued in the 2010‑2025 MHz band, so as to ensure that high levels of emission from transmitters operated under a licence are kept within the geographic area and frequency band of the licence.
Note 1 ACMA may refuse to register a transmitter if the operation of the transmitter could cause an unacceptable level of interference to the operation of other radiocommunications devices — see section 145 of the Act.
Note 2 ACMA may register a transmitter whose operation could cause an unacceptable level of interference to the operation of other radiocommunications devices, when guard space, provided either within a single licence or within a number of shared licences, is used to achieve the levels of isolation for emissions transmitted between spectrum spaces to the same extent as provided by this Determination and other licence conditions. ACMA has issued written advisory guidelines under section 262 of the Act about the registration and operation of transmitters that could cause an unacceptable level of interference to the operation of other radiocommunications devices. The guidelines are:
·Radiocommunications Advisory Guidelines (Registration of Transmitters without an Interference Impact Certificate) 1998.
Note 3 ACMA has issued written advisory guidelines under section 262 of the Act about compatibility requirements in relation to the assignment of frequencies to transmitters operated under apparatus licences and the operation of transmitters under spectrum licences. ACMA may take these guidelines into account during the settlement of interference disputes. Each case will be assessed on its merits. The guidelines do not prevent a licensee negotiating other compatibility requirements with another licensee. The guidelines are:
·Radiocommunications Advisory Guidelines (Protection of Apparatus‑licensed and Class‑licensed Receiver — 2010‑2025 MHz Band) 2006;
·Radiocommunications Advisory Guidelines (Managing Out‑of‑Band Interference from Frequency Adjacent Transmitters in Spectrum Licensed Receivers — 2010‑2025 MHz Band) 2006.
Copies of these instruments are available from ACMA.
4 Interpretation
(1) In this Determination, unless the contrary intention appears:
ACMA means the Australian Communications and Media Authority.
Act means the Radiocommunications Act 1992.
antenna height means the effective height of an antenna worked out in accordance with Schedule 3.
Australian National Spheroid means the Australian National Spheroid published in the Gazette on 6 October 1966 and used with the Australian Geodetic Datum 1984.
cell means a square with a side measured in degrees by reference to the Australian National Spheroid.
centre location, in relation to a transmitter, means the centre location of the transmitter calculated in accordance with Schedule 1.
device boundary, in relation to a transmitter or a group of transmitters operated under a spectrum licence, means the device boundary established in accordance with Part 1 of Schedule 2.
device boundary criterion (2010‑2025 MHz) means the value of the mathematical expression calculated in accordance with Part 2 of Schedule 2.
effective occupied bandwidth, for a transmitter, means the minimum width of a frequency band having fixed upper and lower limits that is necessary to contain not less than 99% of the true mean power of the transmitter’s emission at any time.
effective radius, for a centre location, means the value in kilometres of the effective radius for the centre location, calculated in accordance with Schedule 1.
emission centre frequency, in relation to a transmitter, means the frequency midway between the lower and upper frequency limits of the transmitter’s effective occupied bandwidth.
emission designator has the meaning given by section 8.
error means the uncertainty relating to the measured value of a parameter required to achieve a 95% level of confidence that the true value of the parameter is within the range:
(a) measured value minus the uncertainty; to
(b) measured value plus the uncertainty.
fixed receiver means a receiver located at a fixed point on land or sea and not established for use while in motion.
fixed transmitter means a transmitter located at a fixed point on land or sea and not established for use while in motion.
geographic area, in relation to a spectrum licence, means the area within which operation of a device is authorised under the licence.
group of receivers has the meaning given by section 6.
group of transmitters has the meaning given by section 5.
HAPS means a High Altitude Platform Station, which is a station located on an object at an altitude of 20 to 50 km and at a specified, nominal, fixed point relative to the earth (see No.S1.66A of the Radio Regulations published by the International Telecommunication Union).
horizontally radiated power, for a radiocommunications device, means the product of:
(a) the maximum true mean power within the frequency band of the licence authorising the operation of the device, measured in units of dBm EIRP per 30 kHz at the antenna connector; and
(b) the antenna gain relative to an isotropic antenna in a specified direction reference from, and in the horizontal plane containing, the phase centre of the antenna used with the device.
indoor, in relation to a fixed transmitter, means that the transmitter has an antenna:
(a) located within an enclosed space; and
(b) with its phase centre at least 5 metres from the external surface of the part of the enclosed space which its half‑power beamwidth illuminates.
maximum true mean power means the true mean power measured in a 30 kHz rectangular bandwidth that is located within a specified frequency band such that the true mean power is the maximum of true mean powers produced.
Note The power within a 30 kHz rectangular bandwidth is normally established by taking measurements using either an adjacent channel power meter or a spectrum analyser. The accuracy of measuring equipment, measurement procedure and any corrections to measurements necessary to take account of practical filter shape factors would normally be in accordance with good engineering practice.
mean power means the average power measured during an interval of time that is at least 10 times the period of the lowest modulation frequency.
mobile transmitter means a transmitter established for use while in motion or during halts at unspecified points on land or sea.
outdoor, in relation to a fixed transmitter, means that the transmitter is not an indoor fixed transmitter.
portable, in relation to a transmitter, means that the transmitter may be operated as either a fixed transmitter or a mobile transmitter.
publish includes publish electronically.
RadDEM means the digital elevation model developed by ACMA for radiocommunications purposes that contains modelled terrain height information for Australia in cells of a size of 9 seconds of arc, published by ACMA.
Note Copies of the RadDEM are available from ACMA.
spectrum map grid means the map grid developed by ACMA for Australia, showing cells the sides of which measure 3 degrees of arc, 1 degree of arc or 5 minutes of arc, published by ACMA, copies of which are available from ACMA.
true mean power means:
(a) if an unmodulated carrier is present — the mean power measured while the unmodulated carrier is present; and
(b) if an unmodulated carrier is not present — the mean power measured while transmitted information is present.
Note The following terms, used in this Determination, are defined in the Act:
· frequency band
· interference
· spectrum licence
· transmitter.
(2) In this Determination, the range of numbers that identifies a frequency band includes the higher, but not the lower, number.
(3) In this Determination, radiated power values are to be estimated with a level of confidence not less than 95% that the true value of the radiated power remains below the estimated relevant radiated power value plus 2 dB.
5 Group of transmitters
(1) In this Determination, 2 or more fixed transmitters are a group of transmitters if:
(a) they have the same:
(i) emission centre frequency; and
(ii) emission designator; and
(b) they are operated for the purpose of communicating with the same receiver or group of receivers; and
(c) the same identification number is assigned by ACMA to the antenna used with each transmitter.
(2) A transmitter may belong to more than 1 group of transmitters.
6 Group of receivers
(1) For the purpose of this Determination, 2 or more fixed receivers are a group of receivers if:
(a) they are operated for the purpose of communicating with the same transmitter or group of transmitters; and
(b) the same identification number is assigned by ACMA to the antenna used with each receiver.
(2) A receiver may belong to more than 1 group of receivers.
Note The antenna height of a group of receivers is calculated using the same method as that for a group of transmitters.
7 Unacceptable level of interference
(1) This section sets out what are unacceptable levels of interference for the purposes of section 145 of the Act.
Note Under section 145, ACMA may refuse to register a transmitter if the operation of the transmitter could cause an unacceptable level of interference to the operation of other radiocommunications devices.
(2) A level of interference caused by a transmitter operated under a spectrum licence issued for the 2010‑2025 MHz band is unacceptable if the operation results in a breach of a core condition of the licence relating to the maximum permitted level of radio emission from the transmitter:
(a) outside the parts of the spectrum the use of which is authorised by the licence; or
(b) outside the geographic area of the licence.
Note Subsection 66 (1) of the Act provides that a spectrum licence must include core conditions specifying the maximum permitted level of radio emissions that may be caused by the operation of radiocommunications devices under the licence (see paragraphs 66 (1) (b) and (d) of the Act).
(3) If the licensee of a spectrum licence (the first licence) issued for the 2010‑2025 MHz band has an agreement, for the purpose of core condition 7 of the first licence, with the licensee of another spectrum licence issued for the 2010‑2025 MHz band (the second licence), a level of interference caused by a transmitter operated under the first licence is unacceptable if any part of the device boundary of the transmitter lies outside:
(a) the geographic area of the first licence; and
(b) the geographic area of the second licence.
(3A) If the licensee of a spectrum licence (the first licence) issued for the 2010‑2025 MHz band is the licensee of another spectrum licence issued for the 2010‑2025 MHz band (the second licence), and the geographic area of the second licence is adjacent to the geographic area of the first licence, a level of interference caused by a transmitter operated under the first licence is unacceptable if any part of the device boundary of the transmitter lies outside:
(a) the geographic area of the first licence; and
(b) the geographic area of the second licence.
(3B) If neither subsection (3) nor (3A) applies, a level of interference caused by a transmitter operated under a spectrum licence issued for the 2010‑2025 MHz band is unacceptable if any part of the device boundary of the transmitter lies outside the geographic area of the licence.
(4) If a device boundary of a fixed transmitter cannot be established in accordance with Schedule 2, the transmitter is taken to cause an unacceptable level of interference.
(5) Despite subsections (3), (3A), (3B) and (4), interference caused by a transmitter that operates in the 2010‑2025 MHz band that is:
(a) a mobile transmitter with a horizontally radiated power always less than or equal to 21 dBm EIRP per 30 kHz; or
(b) a portable transmitter with a horizontally radiated power always less than or equal to 21 dBm EIRP per 30 kHz; or
(c) an indoor fixed transmitter with a horizontally radiated power always less than or equal to 21 dBm EIRP per 30 kHz; or
(d) an outdoor fixed transmitter with a horizontally radiated power always less than or equal to 40 dBm EIRP per 30 kHz and an antenna height above the ground not greater than 5 metres; or
(e) a HAPS;
is taken not to be an unacceptable level of interference if the transmitter operates in accordance with the core conditions of its licence.
Note ACMA does not intend to require the registration of certain types of mobile, portable, indoor fixed and outdoor fixed transmitters — see subsection 69 (2) of the Act and the registration conditions of spectrum licences.
(6) A mobile or portable transmitter that operates in the 2010‑2025 MHz band with a horizontally radiated power greater than 21 dBm EIRP per 30 kHz is taken to cause an unacceptable level of interference.
8 Emission designator
For the purpose of working out the emission designator of a transmitter, the references in Article S1 of the Radio Regulations published by the International Telecommunication Union to necessary bandwidth for a given class of emission are taken to be references to the effective occupied bandwidth of the transmitter.
Schedule 1 Centre location and effective radius of a transmitter
(subsection 4 (1))
Note A model for the locations of a group of transmitters (the effective location) is the circumference of the circle defined by the centre location and the effective radius.
1. The centre location of a transmitter is the centre of a circle lc with an effective radius re. This Schedule sets out the lc and re of particular transmitters.
Centre location and effective radius of a fixed transmitter
2. For a fixed transmitter, lc is the location (by latitude and longitude with reference to the Australian National Spheroid) of the phase centre of the transmitter’s antenna and re is zero.
In measuring the latitude and longitude, the following errors are acceptable:
(a) in a high density area ¾ less than 10 metres, measured using, for example, a GPS unit;
(b) in a medium density area ¾ less than 100 metres;
(c) in any other area ¾ less than 1 kilometre.
Note 1 ACMA issues site identifiers for established radiocommunications locations.
Note 2 High density and medium density areas are defined in the Radiocommunications (Transmitter Licence Tax) Determination 2000 and the Radiocommunications (Receiver Licence Tax) Determination 2000 published by ACMA.
Centre location and effective radius of a group of fixed transmitters located near a central point
3. For a group of fixed transmitters:
(a) supported by the same structure; and
(b) having the phase centre of each transmitter’s antenna located within 10 metres of the same central point;
lc is the central point and re is zero.
Centre location and effective radius of a group of fixed transmitters not covered by clause 3
4. For a group of fixed transmitters not covered by clause 3, if each transmitter in the group operates with a horizontally radiated power not exceeding 40 dBm EIRP/30 kHz, and an antenna height above ground not exceeding 10 metres, and is operated in a manner that would result in less than 5% likelihood of causing interference to a receiver over any 20 mS period, then:
(a) lc is:
(i) if the group is operating to a receiver located within the geographic area of the group ¾ the location of that receiver; or
(ii) in any other case ¾ the centre point of the straight line joining the 2 transmitters with the greatest separation distance within the group; and
(b) re is the greater of:
(i) 15; and
(ii) the greatest distance to the centre point lc from any transmitter in the group.
Schedule 2 Device boundaries
(subsection 4 (1))
Part 1 Device boundary of a transmitter or a group of transmitters
Note It is not necessary to calculate a device boundary for certain types of mobile, portable and fixed transmitters as ACMA does not intend to require these to be registered — see subsection 69 (2) of the Act and the registration conditions of spectrum licences.
1. The device boundary of a transmitter is established as follows:
Step 1: Calculate the device boundary criterion (2010‑2025 MHz) (see Part 2) for each increment (m·5) minutes in distance by reference to the Australian National Spheroid, where m is any integer beginning 1 to 30, along each of 144 radials. All increments m=1, begin at the common central point of the radials. The common central point is the centre location of the transmitter. The 144 radials have bearings taken clockwise and given by the sequence f0, f1, f2,...f142, f143, (fn) according to the sequence rule fn = ( (n·5/2) + 5/4) degrees referenced to true north.
Note In the expression “m·5”, and similar expressions, the symbol “ · ” represents the operation of multiplication.
Step 2: Calculate an end point for each radial as the point corresponding to the sum of:
(a) the distance in kilometres along the radial equal to the length corresponding to the number of 5 minute increments from the centre location of the transmitter that corresponds to the calculated value of the device boundary criterion (2010‑2025 MHz) being zero or negative when either all the previous values calculated for that radial are positive, or the number of the increment is equal to 1; and
(b) the effective radius of the centre location.
Note 1 The value of “m” for each increment is the same as the value of “m” for the segment referred to in paragraph 3 (a) of Schedule 3.
Note 2 The actual distance in kilometres for a 5 minute increment in distance varies according to the direction and location of the radial by reference to the Australian National Spheroid. Distances measured in minutes are accepted usage in mapping.
Step 3: Identify the location of each end point by reference to the spectrum map grid.
Step 4: Connect the end point of each radial consecutively to draw a polygon in relation to the spectrum map grid cells.
Step 5: Aggregate the spectrum map grid cells that either fall within or are intersected by the polygon. The boundary of this aggregated area is the device boundary of the transmitter.
2.(1) For a group of fixed transmitters with an effective radius of zero:
(a) the device boundary of the group is to be calculated as if for a single transmitter; and
(b) when calculating the device boundary criterion (2010‑2025 MHz), for each transmitter in the group the horizontally radiated power is calculated in accordance with subclause (2).
(2) The horizontally radiated power is taken:
(a) to be equal for each bearing fn; and
(b) to have a value that is greater than or equal to the horizontally radiated power, in any direction, of any transmitter in the group.
3.(1) For a group of fixed transmitters with an effective radius greater than zero and with a horizontally radiated power not exceeding 40 dBm EIRP/30 kHz and an antenna height above ground not exceeding 10 metres and each transmitter in the group is operated in a manner that would result in less than 5% likelihood of causing interference to a receiver over any 20 mS period:
(a) the device boundary of the group is to be calculated as if for a single transmitter; and
(b) when calculating the device boundary criterion (2010‑2025 MHz), for each transmitter in the group the horizontally radiated power is calculated in accordance with subclause (2).
(2) The horizontally radiated power is taken:
(a) to be equal for each bearing fn; and
(b) to have a value that is greater than or equal to the horizontally radiated power, in any direction, of any transmitter in the group.
Part 2 Device boundary criterion (2010‑2025 MHz)
The device boundary criterion (2010‑2025 MHz) is the value of the mathematical expression:
Note Applying Step 2 of Part 1 the device boundary of a radial (sector) is the distance where the device boundary criterion diminishes to zero or first becomes a negative value plus effective radius of the centre location. That is: distance at (HRP – PL +Gr‑LOP ≤ 0) + re.
where:
HRP is the horizontally radiated power (dBm EIRP/30kHz) for each bearing fn, where the radiated power is to be estimated with a level of confidence not less than 95% that the true value of the radiated power remains below the estimated relevant radiated power value plus 2 dB.
LOP is the level of protection (‑75.2 dBm/30 kHz, with receiver antenna height (hgr) of 30m).
Gr is the nominal receive antenna gain including feeder loss (22.8 dBi, being antenna gain of 24.8 dBi and 2dB feeder loss).
PL is propagation loss in units of dB calculated as set out below, being a function of hagm(fn) and dm(fn),
where:
hagm (fn) is the average ground height measured in metres for segment m (m being any integer from 1 to 30) for each bearing fn; and
dm(fn) is the distance m×5 minutes with reference to the Australian National Spheroid, calculated for segment m and measured in kilometres with an error of less than ± 0.5 km, for each bearing fn.
PL(hagm(fn), dm(fn)) measured in units of dB, for a transmitter that operates with part of its effective occupied band within the 2010‑2025 MHz band, is calculated by analysing the path from the location of the transmitter to dm(fn) as set out in Part 3.
An overview of the calculation of propagation loss is at Schedule 4.
Part 3 Calculation of Propagation Loss
In calculating PL(hagm(fn), dm(fn)):
The operation of multiplication is represented by the symbol “ · ”.
f : nominal frequency in MHz = 2025.
rearth : effective earth radius in kilometres = 8500.
: wavelength in metres = (3·108 )/(2025·106).
hgt : is the transmitter antenna height above ground in metres determined as defined in Schedule 3.
hgr : is the nominal receiver antenna height above ground in metres = 30.
hs : is transmitter antenna height above sea level in metres as defined in Schedule 3.
dj(fn), di(fn), dk(fn) and dp(fn) are distances in kilometres calculated using the methodology for Part 2 where the values of j, i, k, and p indicate for which segment the distance is being calculated.
hagj(fn), hagi(fn), hagk(fn) and hagp(fn) are heights measured in metres and are calculated using the methodology for calculating average ground height as outlined in Schedule 3 where the values of j, i, k and p indicate for which segment the average height is being calculated.
For sector “n” path loss PL(hagm(fn), dm(fn)) is
For segment m=1
PL(hag1(fn), d1(fn)) = 32.5 + 20·log (d1(fn)) + 20·log(f).
For segment m=2
PL(hag2(fn), d2(fn)) is calculated by analysing the path from the location of the transmitter to d2(fn) (see Diagram 1).
Diagram 1
Path for transmitter to d2(fn)
For simplification let
ha = hs hb = hgr + hag2(fn) hn = hag1(fn) h = h1 dan = d1(fn) dnb = d2(fn) – d1(fn) dab = d2(fn) Then
PL(hag2(fn), d2(fn)) = 32.5 + 20·log (d2(fn)) + 20·log(f) + J(v)
Where
for n > ‑0.78
J(n) = 0 for n £ – 0.78
For segments m=3 to 30
PL(hagm(fn), dm(fn)) =32.5 + 20·log (dm(fn)) + 20·log(f) + L
Where
L = J(np ) + T· [ J(nt ) + J(nr ) + C ] for np > – 0.78
L = 0 for np £ – 0.78
C = 10.0 + 0.04· dm(fn)
T = 1.0 – exp [ –J(np ) / 6.0 ]
J(np ), J(nt ), and J(nr ) are calculated as set out in steps 1 to 3.
Step 1: Calculate J(np )
J(np ) is calculated by analysing the path from the location of the transmitter to dm(fn) (see Diagram 2).
Diagram 2
Path for transmitter to dm(fn)
For simplification let
ha = hs hb = hgr + hagm(fn) hnj = hagj(fn) danj = dj(fn) dnbj = dm(fn) – dj(fn) dab = dm(fn) For the path from transmitter to point m calculate np , the maximum value of nj (ie np = max(nj )) and hence the value p = value of j that gives max (nj) where:
j = 1 to m‑1
Then J(np) is given by:
for np > ‑0.78
J(np ) = 0 for np £ – 0.78
Step 2: Calculate J(nt )
If p=1, then J(nt ) =0; Else J(nt ) is calculated by analysing the path from the location of the transmitter to the point p (see Diagram 3).
Diagram 3
Path for transmitter to point p
For simplification let
ha = hs hb = hagp(fn) hni = hagi(fn) dani = di(fn) dnbi = dp(fn) – di(fn) dab = dp(fn) For the path profile from transmitter to the path to p (determined by np, see step 1) calculate nt , the maximum value of ni where:
i = 1 to p‑1
Then J(nt) is given by:
for nt > ‑0.78
J(nt ) = 0 for nt £ – 0.78
Step 3: Calculate J(nr)
If p=m‑1, then J(nr) =0; Else J(nr) is calculated by analysing the path from the point p to the point dm(fn) (see Diagram 4).
Diagram 4
Path for point p to dm(fn)
For simplification let
ha = hagp(fn) hb = hgr + hagm(fn) hnk = hagk(fn) dank = dk(fn) – dp(fn) dnbk = dm(fn) – dk(fn) dab = dm(fn) – dp(fn) For the path profile from the point p (determined by np, see step 1) to the point dm(fn) calculate nr , the maximum value of nk, where:
k = p+1 to m‑1
Then J(nr) is given by:
for nr > ‑0.78
J(nr) = 0 for nr £ – 0.78
Schedule 3 Average Ground Height and Transmitter Antenna Height
(subsection 4 (1))
1.The average ground height and transmitter antenna height are determined as set out in this Schedule.
Antenna height of a fixed outdoor transmitter (see Diagram 1)
2. (a) hgt is the vertical height in metres of the phase centre of the fixed transmitter’s antenna measured with an error of less than 5 parts in 100 and relative to the point:
(i) located on the line of intersection between the external surface of the structure supporting the antenna and the surface of the ground or sea; and
(ii) having the lowest elevation on that line; and
(b) hs is the sum of:
(i) the elevation attribute of the RadDEM cell containing the location of the phase centre of a fixed transmitter’s antenna; and
(ii) hgt.
Average ground height (see Diagram 1)
3. If:
(a) each sector is divided into 30 segments ‘m’ (as illustrated in Diagram 2 below) with:
(i) any 2 consecutively numbered segments 1 to 30 being contiguous; and
(ii) each segment being a 5 minute increment in radial distance; and
(iii) segment 1 beginning at the centre location;
then hagm(fn), the average ground height:
(b) for each of the segments ‘m’ of a sector of 2.5 degrees arc centred along each of the bearings fn, is calculated by taking the average of the elevation attributes for all of the cells that have either half (with an error of less than 1 part in 64) or more than half their area within each segment ‘m’.
Note 1 A RadDEM cell is represented as raster data such that the western and southerly boundary of the cell is part of the cell but the northerly and easterly boundary is part of the adjacent cells. This is an important consideration when a location falls on a cell boundary.
Note 2 A RadDEM cell is considered to be half within a sector/segment with an error of less than 1 part in 64 when the centre locations of 64 sub‑cells that compose the cell are within the sector/segment.
Antenna height of a group of fixed transmitters located near a central point
4. For a group of fixed transmitters:
(a) all supported by the one structure; and
(b) having the phase centre of each transmitter’s antenna located within 10 metres of the same central point;
the antenna height of the group is calculated as if it is a single fixed transmitter located at the central point and with a hgt, calculated in accordance with paragraph 2 (a), equal to that calculated for the antenna with the largest hgt.
Antenna height of a group of fixed outdoor transmitters with an effective radius greater than zero
5. For a group of fixed transmitters with a horizontally radiated power not exceeding 40 dBm EIRP/30 kHz and an antenna height above ground not exceeding 10 metres, if each transmitter in the group is operated in a manner that would result in less than 5% likelihood of causing interference to a receiver over any 20 mS period, the antenna height hgt, is 10 metres.
Antenna height of an indoor fixed transmitter
6. The antenna height of an indoor fixed transmitter is hgt metres, where hgt is the smallest distance, measured vertically, between the phase centre of the transmitter’s antenna and any surface in the building where the transmitter is located and on which mobile transmitters are supported.
Diagram 1
Calculating Average Antenna Height
Diagram 2
Segments and sectors
Schedule 4 Overview of Propagation Loss (Modified extract from Rec ITU‑R P.526.8)
Propagation loss is calculated as free space loss plus knife edge diffraction loss based on the Deygout method limited to a maximum of 3 edges. Calculating diffraction loss is based on a procedure which is used from 1 to 3 times depending on the path profile. The procedure consists of finding the point within a given section of the profile with the highest value of the geometrical parameter n. The section of the profile to be considered is defined from point index a to point index b (a < b). If a + 1 = b there is no intermediate point and the diffraction loss for the section of the path being considered is zero. Otherwise the construction is applied by evaluating nn (a < n < b) and selecting the point with the highest value of n. The value of n for the n‑th profile point is given by:
where:
h = hn + [dan dnb / 2 re] – [(ha dnb + hb dan) / dab]
ha, hb, hn : vertical heights as shown in Diagram 1
dan, dnb, dab : horizontal distances as shown in Diagram 1
rearth : effective Earth radius
l : wavelength
and all h, d, rearth and l are in self‑consistent units.
With ha, hb, hn and l in metres, dan, dnb, dab and rearth in kilometres
and
The diffraction loss is then given as the knife‑edge loss J(n) according to the equation
for n > ‑0.78
J(n) = 0 for n £ – 0.78
The geometry of the path profile is illustrated in Diagram 1.
Diagram 1
Geometry of path profile
The above procedure is first applied to the entire profile from transmitter to receiver. The point with the highest value of n is termed the principal edge, p, and the corresponding loss is J(np ).
If np > – 0.78 the procedure is applied twice more:
– from the transmitter to point p to obtain nt and hence J(nt );
– from point p to the receiver to obtain nr and hence J(nr ).
The excess diffraction loss for the path is then given by:
L = J(np ) + T [ J(nt ) + J(nr ) + C ] for np > – 0.78
L = 0 for np £ – 0.78
where:
C : empirical correction
C = 10.0 + 0.04D
D : total path length (km)
and
T = 1.0 – exp [ –J(np ) / 6.0 ].
0
0
0