UNITED STATES

**PRELIMINARY VIEWS ON WRC-07**

**Agenda Item 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)**;

**ISSUE:** Taking into account the results of the compatibility studies,
including the impact on the active and passive services concerned,
consider which band pairs (contained in the Table to Resolution **740**)
need to be added to the consultation provisions of Resolution **739
(WRC-03)**? If so, what are the appropriate threshold levels for
consultation?

**BACKGROUND:** In preparation for WRC--03, Task Group 1/7 conducted
studies that led to the adoption of Recommendation ITU--R SM.1633, which
contains nine Annexes that, using the methodology contained in the
Recommendation, assess the compatibility of various band pairs between
the radio astronomy service and space services. Not all studies in the
Annexes are complete. On the basis of Recommendation SM.1633 and
associated studies, WRC-03 adopted Resolutions **739** and **740**.

Resolution **739** contains guidance to administrations operating space
and radio astronomy stations in the band pairs contained in Tables 1-1
and 1-2, in order to come to acceptable solutions regarding space
station unwanted emissions at a radio astronomy station. The Resolution
includes a consultation process adopted at WRC-03 to assist
administrations in reaching mutually acceptable solutions when unwanted
emissions from space services exceed specified levels in certain radio
astronomy bands. The consultation process is included is included in
Resolution **739** and it will not be considered at WRC-07.

Resolution **740** calls for the completion of studies for the band
pairs indicated in its associated band-pair Table. Comprehensive studies
are needed to determine whether any of the band pairs from the Table of
Resolution **740** should be added to the tables in Resolution **739**,
and, if so, to determine the impact on all the concerned active and
passive services and the appropriate threshold levels for consultation.
In accordance with the *resolves 1* of the Resolution **740**, only the
band pairs listed in the Table of Resolution **740** are to be
considered by WRC-07.

**U.S. VIEW:**

1.  Satisfactory studies in ITU-R TG 1/9 need to be completed before a
    determination is made regarding adding any of pairs contained in
    Resolution **740** to the Table in Resolution **739**. The studies
    must identify the appropriate threshold levels for consultation and
    the impact on the concerned active and passive radio services.

2.  The scope of Agenda Item 1.21 is limited to consideration of the
    band pairs in the table of Resolution **740** (and the associated
    threshold levels for consultation), for purpose of making
    appropriate additions from this table to the existing tables in
    Resolution **739**. Any other proposals for modifications to
    Resolution **739** would be clearly outside the scope of this agenda
    item and would not be appropriate.