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  **World Radiocommunication Conference (WRC-07)\  ![](media/image1.png){width="1.9270833333333333in"
  Geneva, 22 October - 16 November 2007**          height="0.8125in"}

                                                   

                                                   

  **PLENARY MEETING**                              **Addendum 21 to\
                                                   Document 41-E**

                                                   **22 August 2007**

                                                   **Original: English**

  Asia-Pacific Telecommunity Administrations       

  common proposals for the work of the conference  

                                                   

  Agenda item 1.21                                 
  ------------------------------------------------ ----------------------------------------------------

1.21 to consider the results of studies regarding the compatibility
between the radio astronomy service and the active space services in
accordance with Resolution **740 (WRC‑03)**, in order to review and
update, if appropriate, the tables of threshold levels used for
consultation that appear in the Annex to Resolution **739** **(WRC‑03)**

Introduction

Agenda item 1.21 addresses the compatibility between the radio astronomy
service and active space services in adjacent or nearby bands as
specified in Resolution 740 (WRC‑03). The results of the studies carried
out for each band-pair under this agenda item are documented in
Report ITU‑R SM.2091 which replaces Recommendation ITU‑R SM.1633 for the
purpose of both Resolutions 739 (WRC‑03) and 740 (WRC‑03).

Resolution 739 (WRC‑03) contains threshold levels based on the results
of the studies prior to WRC‑03 and provides a consultation process that
addresses the case when the threshold levels in specific bands are
exceeded by the active space services. Additional studies have been
carried out under this agenda item for band pairs listed in
Resolution 740 (WRC‑03) and provide additional threshold levels.

One method to satisfy the agenda item is to add the threshold levels to
Resolution 739 (WRC‑03) for those bands for which studies have been
concluded. Another method is to add the threshold levels to that
Resolution but to specifically exclude the radionavigation-satellite
service systems for the band-pair 1 559‑1 610 МHz/1 610.6-1 613.8 MHz
from that Resolution. A third method is to add appropriate threshold
levels to Table 1-1 of Resolution 739 (WRC‑03).

APT recognizes the great worldwide importance of RNSS systems and does
not wish to limit any future RNSS developments. At the same time, APT
recognizes the importance of the RA service. All but one of the current
or proposed RNSS systems meet the RAS protection criteria. APT is of the
opinion that technological developments would enable all future RNSS
systems to meet the RAS protection criteria. APT would urge the RAS
community and the RNSS community to consult with each other for a
satisfactory solution.

**MOD** ASP/41A21/334

RESOLUTION 739 (Rev.WRC‑07)

Compatibility between the radio astronomy service and the active\
space services in certain adjacent and nearby frequency bands

The World Radiocommunication Conference (Geneva, 2007),

considering

*a)* that adjacent or nearby primary service allocations have been made
to the radio astronomy service, and to various space services, such as
the fixed‑satellite service (FSS), radionavigation-satellite service
(RNSS), mobile‑satellite service (MSS) and broadcasting‑ satellite
service (BSS), hereafter referred to as "active space services";

*b)* that, in many cases, the frequencies used by the radio astronomy
service (RAS) are chosen to study natural phenomena producing radio
emissions at frequencies fixed by the laws of nature, so shifting
frequency to avoid or mitigate interference problems may not be
possible;

*c)* that Report ITU‑R SM.2091 provides a methodology for conducting,
and a framework for documenting the results of, compatibility studies
between active space service and passive service band-pairs;

*d)* that Report ITU‑R SM.2091 also provides the results of
compatibility studies between a passive service and an active space
service in certain adjacent and nearby bands;

*e)* that appropriate consultation between administrations has the
potential to lead to the development of innovative solutions and to the
rapid deployment of systems;

*f)* that, for technical or operational reasons, more stringent spurious
emission limits than the general limits in Appendix **3** may be
required to protect the RAS from active services in specific bands,

noting

*a)* that the additional burden of undertaking any technical examination
should not be placed on the Radiocommunication Bureau;

*b)* that a consultation procedure, as contained in this Resolution,
would not place an additional burden on the Bureau;

*c)* that Recommendation ITU‑R M.1583 provides a methodology based on
the equivalent power flux-density (epfd) concept for calculation of
interference resulting from unwanted emissions from non-geostationary
(non-GSO) satellite systems of the MSS or RNSS into radio astronomy
stations;

*d)* that Recommendation ITU‑R S.1586-1 provides a methodology based on
the epfd concept for calculation of interference resulting from unwanted
emissions from non-GSO systems of the FSS into radio astronomy stations;

*e)* that Recommendation ITU‑R RA.1631 provides antenna patterns to be
used for compatibility analyses between non‑GSO systems and RAS
stations, based on the epfd concept;

*f)* that Recommendation ITU‑R RA.1513-1 provides acceptable levels of
data loss to radio astronomy observations, stating in particular that
the percentage of data loss caused by any system should be lower than
2%;

*g)* that some of the results documented in Report ITU‑R SM.2091 may be
used as threshold levels to initiate the consultation procedure;

*h)* that the results of successful consultation between concerned
administrations would ensure that the interests of both the active and
passive services are considered;

*i)* that measures taken by active space services to protect radio
astronomy stations from interference may result in increased costs
and/or reduced capabilities for those services;

*j)* that conversely, not taking such measures may result in additional
operating costs and reduced operational effectiveness for the radio
astronomy stations concerned;

*k)* that the implementation of additional interference mitigation
measures at the radio astronomy station may increase operating costs and
reduce observational effectiveness;

*l)* that conversely, not implementing such measures may impose upon the
active space services an additional cost burden and reduction in service
capability;

*m)* that studies for some of the band-pairs listed in Report
ITU‑R SM.2091 are still in progress,

recognizing

*a)* that unwanted emissions produced by stations of the active space
services may cause unacceptable interference to stations of the RAS;

*b)* that, although some unwanted emissions from transmitters on space
stations can be controlled through careful design methods and
appropriate testing procedures, other unwanted emissions, such as
narrowband spurious emissions, generated by uncontrollable and/or
unpredictable physical mechanisms, may only be detected after the
spacecraft is launched;

*c)* that there is an uncertainty in the pre-launch assessment of the
levels of unwanted emissions;

*d)* that it is necessary to ensure an equitable sharing of burden for
achieving compatibility between the active space services and the RAS;

*e)* that for those cases where difficulties are encountered in meeting
the values in the Annex, a consultation procedure could be used to
resolve the difficulties,

resolves

1 that an administration takes all reasonable steps to ensure that space
stations being designed and constructed to operate in the bands in the
Annex 1 meet the values given therein at any radio astronomy station
operating in the corresponding bands identified in this Annex;

2 that in the event that during construction and prior to launch it is
determined that, after having considered all reasonable means, the
unwanted emissions from the space station cannot meet the values given
in the Annex 1, the administration that notified the space station
contacts, as soon as possible, the administration operating the radio
astronomy station to confirm that *resolves* 1 has been fulfilled, and
the concerned administrations enter into a consultation process in order
to identify all practicable steps with a view to achieving a mutually
acceptable solution;

3 that in the event, following the space station launch, an
administration operating a radio astronomy station determines that, due
to unexpected circumstances, a space station does not meet the values
for unwanted emissions given in the Annex 1 at that radio astronomy
station, it contacts the administration that notified the space station
so that the administration that notified the space station confirms that
*resolves* 1 has been fulfilled, and the concerned administrations enter
into a consultation process in order to identify further steps with a
view to achieving a mutually acceptable solution;

4 that the radio astronomy stations to be taken into account in applying
*resolves* 1, 2 and 3 are those which are operating in the frequency
band(s) identified in the Annex 1 and which are notified before the date
of reception of the advance publication information of the space station
to which this Resolution applies;

5 that the space stations to be considered in the application of the
above *resolves* are those designed to operate in the space service
frequency bands listed in the Annex 1 for which advance publication
information is received by the Bureau following the entry into force of
the Final Acts of this conference;

6 that the objective of the consultation process in *resolves *1, 2
and 3 is to achieve a mutually acceptable solution, using as guidance
Report ITU‑R SM.2091 and any other ITU‑R Recommendations deemed relevant
by the concerned administrations;

7 that the Bureau shall make no examination or finding with respect to
this Resolution under either Article **9** or **11**,

invites administrations

1 to take all appropriate and practicable steps, from the design phase
onward, to ensure that unwanted emissions are minimized from space
stations that are planned to operate in one or more space service
allocations, in order to avoid exceeding the threshold levels of
unwanted emissions identified in the Annex 1 at any radio astronomy
station;

2 to take all practicable steps, from the design phase onward, to
minimize the sensitivity of radio astronomy stations to interference and
to take into account the need to implement interference mitigation
measures.

ANNEX 1 TO RESOLUTION 739 (Rev.WRC-07)

Unwanted emission threshold levels

The unwanted emission threshold levels applicable to geostationary space
stations are given in Table 1‑1 in terms of power flux-density (pfd) in
a reference bandwidth produced at a radio astronomy station.

In Table 1‑1 the unwanted emission threshold levels given in the fourth,
sixth and eighth columns (associated with the reference bandwidth
contained in the adjacent columns) should be met by space stations
operating in the bands indicated in the second column at the radio
astronomy station operating in the band mentioned in the third column.

The unwanted emission threshold levels applicable to space stations of
non-geostationary systems are given in Table 1‑2 in terms of the
equivalent power flux-density (epfd), produced at a radio astronomy
station in a reference bandwidth, not to be exceeded during a given
percentage of time, over the whole sky.

In Table 1‑2 the epfd value given in the fourth, sixth and eighth
columns (associated with the reference bandwidths contained in the
adjacent column) should be met by space stations operating in the bands
indicated in the second column at the radio astronomy station operating
in the band mentioned in the third column. The epfd value at a given
radio astronomy station shall be evaluated by using the antenna pattern
and the RAS maximum antenna gain given in Recommendation ITU‑R RA.1631.
Guidance on the calculation of epfd can be found in Recommendations
ITU‑R S.1586-1 and ITU‑R M.1583. The elevation angles of the radio
astronomy stations to be taken into account in the epfd calculation are
those higher than the minimum elevation angle θ*~min~* of the radio
telescope. In the absence of such information a value of 5° shall be
taken. The percentage of time during which the epfd level shall not be
exceeded is mentioned in Note ^(1)^ of Table 1‑2.

TABLE 1-1

pfd thresholds for unwanted emissions from geostationary space stations\
at a radio astronomy station

TABLE 1-2

epfd thresholds^\*^ for unwanted emissions from non-GSO satellite
systems\
at a radio astronomy station

**Reasons:** Recommendation ITU-R SM.1633 has been replaced by Report
ITU-R SM.2091. For some band pairs ITU-R has completed compatibility
studies and concluded that the unwanted emissions from active space
services can meet, without undue constraints, the threshold interference
levels detrimental to the radio astronomy service. There is a minor
editorial change due to the update of Recommendation ITU-R RA.769.

ARTICLE 5

Frequency allocations

Section IV -- Table of Frequency Allocations\
(See No. 2.1)

**MOD** ASP/41A21/335

**5.347A** In the bands:

137-138 MHz,\
387-390 MHz,\
400.15-401 MHz,\
620-790 MHz,\
1 452-1 492 MHz,\
1 525-1 559 MHz,\
1 613.8-1 626.5 MHz,\
2 655-2 670 MHz,\
2 670-2 690 MHz,\
21.4-22 GHz,

Resolution **739** **(Rev.WRC-07)** applies.     (WRC-07)

**Reasons:** Consequential to the changes in ASP/41A21/334, also minor
editorial changes in the frequency band 1 613.8-1 626.5 MHz.

**MOD** ASP/41A21/336

75.2-137.175 MHz

+----------------------+----------------------+-----------------------+
| Allocation to        |                      |                       |
| services             |                      |                       |
+----------------------+----------------------+-----------------------+
| Region 1             | Region 2             | Region 3              |
+----------------------+----------------------+-----------------------+
| **137-137.025**      |                      |                       |
| SPACE OPERATION      |                      |                       |
| (space-to-Earth)     |                      |                       |
|                      |                      |                       |
| METE                 |                      |                       |
| OROLOGICAL-SATELLITE |                      |                       |
| (space-to-Earth)     |                      |                       |
|                      |                      |                       |
| MOBILE-SATELLITE     |                      |                       |
| (space-to-Earth)     |                      |                       |
| 5.208A 5.209 MOD     |                      |                       |
| 5.347A               |                      |                       |
|                      |                      |                       |
| SPACE RESEARCH       |                      |                       |
| (space-to-Earth)     |                      |                       |
|                      |                      |                       |
| Fixed                |                      |                       |
|                      |                      |                       |
| Mobile except        |                      |                       |
| aeronautical mobile  |                      |                       |
| (R)                  |                      |                       |
|                      |                      |                       |
| 5.204 5.205 5.206    |                      |                       |
| 5.207 5.208          |                      |                       |
+----------------------+----------------------+-----------------------+
| **137.025-137.175**  |                      |                       |
| SPACE OPERATION      |                      |                       |
| (space-to-Earth)     |                      |                       |
|                      |                      |                       |
| METE                 |                      |                       |
| OROLOGICAL-SATELLITE |                      |                       |
| (space-to-Earth)     |                      |                       |
|                      |                      |                       |
| SPACE RESEARCH       |                      |                       |
| (space-to-Earth)     |                      |                       |
|                      |                      |                       |
| Fixed                |                      |                       |
|                      |                      |                       |
| Mobile-satellite     |                      |                       |
| (space-to-Earth)     |                      |                       |
| 5.208A 5.209 MOD     |                      |                       |
| 5.347A               |                      |                       |
|                      |                      |                       |
| Mobile except        |                      |                       |
| aeronautical mobile  |                      |                       |
| (R)                  |                      |                       |
|                      |                      |                       |
| 5.204 5.205 5.206    |                      |                       |
| 5.207 5.208          |                      |                       |
+----------------------+----------------------+-----------------------+

**Reasons:** Consequential to the changes in ASP/41A21/334 and
ASP/41A21/335.

**MOD** ASP/41A21/337

137.175-148 MHz

+-----------------------+-----------------------+-----------------------+
| Allocation to         |                       |                       |
| services              |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Region 1              | Region 2              | Region 3              |
+-----------------------+-----------------------+-----------------------+
| **137.175-137.825**   |                       |                       |
| SPACE OPERATION       |                       |                       |
| (space-to-Earth)      |                       |                       |
|                       |                       |                       |
| MET                   |                       |                       |
| EOROLOGICAL-SATELLITE |                       |                       |
| (space-to-Earth)      |                       |                       |
|                       |                       |                       |
| MOBILE-SATELLITE      |                       |                       |
| (space-to-Earth)      |                       |                       |
| 5.208A 5.209 MOD      |                       |                       |
| 5.347A                |                       |                       |
|                       |                       |                       |
| SPACE RESEARCH        |                       |                       |
| (space-to-Earth)      |                       |                       |
|                       |                       |                       |
| Fixed                 |                       |                       |
|                       |                       |                       |
| Mobile except         |                       |                       |
| aeronautical mobile   |                       |                       |
| (R)                   |                       |                       |
|                       |                       |                       |
| 5.204 5.205 5.206     |                       |                       |
| 5.207 5.208           |                       |                       |
+-----------------------+-----------------------+-----------------------+
| **137.825-138** SPACE |                       |                       |
| OPERATION             |                       |                       |
| (space-to-Earth)      |                       |                       |
|                       |                       |                       |
| MET                   |                       |                       |
| EOROLOGICAL-SATELLITE |                       |                       |
| (space-to-Earth)      |                       |                       |
|                       |                       |                       |
| SPACE RESEARCH        |                       |                       |
| (space-to-Earth)      |                       |                       |
|                       |                       |                       |
| Fixed                 |                       |                       |
|                       |                       |                       |
| Mobile-satellite      |                       |                       |
| (space-to-Earth)      |                       |                       |
| 5.208A 5.209 MOD      |                       |                       |
| 5.347A                |                       |                       |
|                       |                       |                       |
| Mobile except         |                       |                       |
| aeronautical mobile   |                       |                       |
| (R)                   |                       |                       |
|                       |                       |                       |
| 5.204 5.205 5.206     |                       |                       |
| 5.207 5.208           |                       |                       |
+-----------------------+-----------------------+-----------------------+

**Reasons:** Consequential to the changes in ASP/41A21/334 and
ASP/41A21/335.

**(MOD)** ASP/41A21/338

**5.208A** In making assignments to space stations in the
mobile-satellite service in the bands 137-138 MHz, 387-390 MHz and
400.15-401 MHz, administrations shall take all practicable steps to
protect the radio astronomy service in the bands 150.05-153 MHz,
322-328.6 MHz, 406.1-410 MHz and 608-614 MHz from harmful inter­ference
from unwanted emissions. The threshold levels of interference
detrimental to the radio astronomy service are shown in Table 1 of
Recommendation ITU-R RA.769-2.     (WRC-07)

**Reasons:** Minor editorial change by Recommendation ITU-R RA.769-2
(2003).

**MOD** ASP/41A21/339

335.4-410 MHz

+-----------------------+-----------------------+-----------------------+
| Allocation to         |                       |                       |
| services              |                       |                       |
+-----------------------+-----------------------+-----------------------+
| Region 1              | Region 2              | Region 3              |
+-----------------------+-----------------------+-----------------------+
| **387-390** FIXED     |                       |                       |
|                       |                       |                       |
| MOBILE                |                       |                       |
|                       |                       |                       |
| Mobile-satellite      |                       |                       |
| (space-to-Earth)      |                       |                       |
| 5.208A 5.254 5.255    |                       |                       |
| MOD 5.347A            |                       |                       |
+-----------------------+-----------------------+-----------------------+
| **390-399.9** FIXED   |                       |                       |
|                       |                       |                       |
| MOBILE                |                       |                       |
|                       |                       |                       |
| 5.254                 |                       |                       |
+-----------------------+-----------------------+-----------------------+
| **399.9-400.05**      |                       |                       |
| MOBILE-SATELLITE      |                       |                       |
| (Earth-to-space)      |                       |                       |
| 5.209 5.224A          |                       |                       |
|                       |                       |                       |
| RADI                  |                       |                       |
| ONAVIGATION-SATELLITE |                       |                       |
| 5.222 5.224B 5.260    |                       |                       |
|                       |                       |                       |
| 5.220                 |                       |                       |
+-----------------------+-----------------------+-----------------------+
| **400.05-400.15**     |                       |                       |
| STANDARD FREQUENCY    |                       |                       |
| AND TIME SIGNAL-\     |                       |                       |
| SATELLITE (400.1 MHz) |                       |                       |
|                       |                       |                       |
| 5.261 5.262           |                       |                       |
+-----------------------+-----------------------+-----------------------+
| **400.15-401**        |                       |                       |
| METEOROLOGICAL AIDS   |                       |                       |
|                       |                       |                       |
| MET                   |                       |                       |
| EOROLOGICAL-SATELLITE |                       |                       |
| (space-to-Earth)      |                       |                       |
|                       |                       |                       |
| MOBILE-SATELLITE      |                       |                       |
| (space-to-Earth)      |                       |                       |
| 5.208A 5.209 MOD      |                       |                       |
| 5.347A                |                       |                       |
|                       |                       |                       |
| SPACE RESEARCH        |                       |                       |
| (space-to-Earth)      |                       |                       |
| 5.263                 |                       |                       |
|                       |                       |                       |
| Space operation       |                       |                       |
| (space-to-Earth)      |                       |                       |
|                       |                       |                       |
| 5.262 5.264           |                       |                       |
+-----------------------+-----------------------+-----------------------+

**Reasons:** Consequential to the changes in ASP/41A21/334 and
ASP/41A21/335.

**MOD** ASP/41A21/340

460-890 MHz

+----------------------+----------------------+-----------------------+
| Allocation to        |                      |                       |
| services             |                      |                       |
+----------------------+----------------------+-----------------------+
| Region 1             | Region 2             | Region 3              |
+----------------------+----------------------+-----------------------+
| > **470-790**        | > **470-512**        | > **470-585**         |
| >                    | >                    | >                     |
| > BROADCASTING       | > BROADCASTING       | > FIXED               |
| >                    | >                    | >                     |
| > 5.149 5.291A 5.294 | > Fixed              | > MOBILE              |
| > 5.296\             | >                    | >                     |
| > 5.300 5.302 5.304  | > Mobile             | > BROADCASTING        |
| > 5.306\             | >                    | >                     |
| > 5.311 5.312 MOD    | > 5.292 5.293        | > 5.291 5.298         |
| > 5.347A             | >                    | >                     |
| >                    | > **512-608**        | > **585-610**         |
| > **790-862**        | >                    | >                     |
| >                    | > BROADCASTING       | > FIXED               |
| > FIXED              | >                    | >                     |
| >                    | > 5.297              | > MOBILE              |
| > BROADCASTING       | >                    | >                     |
| >                    | > **608-614**        | > BROADCASTING        |
| > 5.312 5.314 5.315  | >                    | >                     |
| > 5.316 5.319 5.321  | > RADIO ASTRONOMY    | > RADIONAVIGATION     |
|                      | >                    | >                     |
|                      | > Mobile-satellite   | > 5.149 5.305 5.306   |
|                      | > except\            | > 5.307               |
|                      | > aeronautical       | >                     |
|                      | > mobile-satellite\  | > **610-890**         |
|                      | > (Earth-to-space)   | >                     |
|                      | >                    | > FIXED               |
|                      | > **614-806**        | >                     |
|                      | >                    | > MOBILE 5.317A       |
|                      | > BROADCASTING       | >                     |
|                      | >                    | > BROADCASTING        |
|                      | > Fixed              |                       |
|                      | >                    |                       |
|                      | > Mobile             |                       |
|                      | >                    |                       |
|                      | > 5.293 5.309 5.311  |                       |
|                      | > MOD 5.347A         |                       |
|                      | >                    |                       |
|                      | > **806-890**        |                       |
|                      | >                    |                       |
|                      | > FIXED              |                       |
|                      | >                    |                       |
|                      | > MOBILE 5.317A      |                       |
|                      | >                    |                       |
|                      | > BROADCASTING       |                       |
+----------------------+----------------------+-----------------------+
|                      | > 5.317 5.318        | > 5.149 5.305 5.306   |
|                      |                      | > 5.307\              |
|                      |                      | > 5.311 5.320 MOD     |
|                      |                      | > 5.347A              |
+----------------------+----------------------+-----------------------+

**Reasons:** Consequential to the changes in ASP/41A21/334 and
ASP/41A21/335.

**MOD** ASP/41A21/341

RESOLUTION 740 (Rev.WRC-07)

Future compatibility analyses between the radio astronomy service and\
active space services in certain adjacent and nearby frequency bands

The World Radiocommunication Conference (Geneva, 2007),

considering

*a)* that adjacent or nearby primary service allocations have been made
to the radio astronomy service (RAS), and to various space services,
such as the fixed-satellite service (FSS), mobile-satellite service
(MSS), broadcasting-satellite service (BSS) and radionavigation
satellite service (RNSS), hereafter referred to as "active space
services";

*b*) that unwanted emissions from active space services may cause
unacceptable interference to the RAS;

*c)* that, for technical or operational reasons, the general limits in
Appendix **3** may be insufficient in protecting the RAS in specific
bands;

*d)* that, in many cases, the frequencies used by the RAS are chosen to
study natural phenomena producing radio emissions at frequencies fixed
by the laws of nature, and therefore shifting frequency to avoid or
mitigate interference problems may not be possible;

*e)* that Report ITU‑R SM.2091 provides a list of band-pairs and a
methodology for conducting, and a framework for documenting the results
of, the compatibility studies between certain active and passive
services operating in specific adjacent and nearby band-pairs;

*f)* that it is necessary to ensure an equitable burden sharing for
achieving compatibility between active and passive services,

recognizing

*a)* that Report ITU‑R SM.2091 addresses the compatibility between the
RAS and the active space services in specific band-pairs;

*b)* that the relevant Annexes in Report ITU‑R SM.2091 need further
refinement;

*c)* that measures beyond the general unwanted emission limits in
Appendix **3** may be required to protect the RAS from unwanted
emissions of active space services for the band-pairs listed in the
Table,

TABLE

Band-pairs to be considered for further studies

resolves

1 to invite ITU‑R to study the compatibility between the RAS and the
corresponding active space services as listed in the Table only, with a
view to updating or developing ITU‑R Recommendations, if appropriate;

2 that future conferences should consider the results of the studies as
identified in *resolves* 1, in order to review and update, if
appropriate, the tables of threshold levels for consultation in the
Annex 1 to Resolution **739** **(Rev.WRC‑07)**,

invites administrations

to actively participate in the ITU‑R studies identified in *resolves* 1
and to provide, where practicable, the relevant characteristics of
active and passive service systems operating in the bands identified in
the Table to this Resolution, as well as to indicate the impact on all
concerned services of implementing or not implementing the compatibility
solutions.

**Reasons:** ITU-R studies have been carried out for some band-pairs
listed in Resolution 740 (WRC‑03) and provide additional threshold
interference levels detrimental to the radio astronomy service. The
remaining band-pairs listed in Resolution 740 (WRC‑03) may need to be
extended for another study period.

\_\_\_\_\_\_\_\_\_\_\_\_