1、C:DOCUMENTS AND SETTINGSQGV33745MY DOCUMENTSDOWNLOADSR-QUE-SG06.30-2002-MSW-E.DOC 22.10.03 15.07.10 QUESTION ITU-R 30/6*Transmitting and receiving antennas at VHF and UHF (1990-1993-1994-1995-2002) The ITU Radiocommunication Assembly, considering a) that transmitting and receiving antenna characteri
2、stics are required for frequency planning; b) that planning the most efficient spectrum use often requires establishing the antenna radiation patterns to a high degree of accuracy; c) that planning the most efficient spectrum use may imply using the same antenna for several emissions; d) that in est
3、ablishing transmitting radiation patterns, account must be taken of the influence of the supporting structure, significant nearby structures and the electrical stability of the antenna assembly; e) that it is essential to verify the antenna radiation pattern by measurements; f) that the RF power den
4、sity in the vicinity of transmitting antennas is significant; g) that the Radiocommunication Study Groups have already made significant studies on the radiation characteristics of LF, MF, HF and satellite antennas; h) that comprehensive information on the characteristics of transmitting and receivin
5、g antenna systems at VHF and UHF (including those for direct satellite broadcasting use at frequencies above 1 GHz) is not readily available in the ITU-R publications, decides that the following Question should be studied 1 What are the radiation patterns of VHF and UHF transmitting and receiving an
6、tenna systems (including those for direct satellite broadcasting use at frequencies above 1 GHz)? 2 What is the influence of supporting structures and significant nearby structures on the technical characteristics of antennas in the VHF and UHF bands? 3 What differences are to be expected between th
7、eoretical and practical performance due to practical aspects of VHF and UHF antennas? 4 What are the methods of calculation of the electric and magnetic field strengths in the vicinity of transmitting antennas? 5 What computer-based procedures can be recommended to give, in a standardized form, the
8、gain and directivity patterns of transmitting and receiving antennas (including those for Direct Satellite Broadcasting use at frequencies above 1 GHz) in common use at VHF and UHF? NOTE 1 See Recommendation ITU-R BS.1195, _ *For studies relating to satellite broadcasting refer to Working Party 6S.
9、- 2 - 6/1-E C:DOCUMENTS AND SETTINGSQGV33745MY DOCUMENTSDOWNLOADSR-QUE-SG06.30-2002-MSW-E.DOC 22.10.03 15.07.10 further decides 1 that the results of the above studies should be addressed to prepare a new Recommendation on: receiving antennas at VHF and UHF (including those for direct satellite broa
10、dcasting use at frequencies above 1 GHz); reference receiving antenna patterns for use in planning; transmitting antennas at VHF and UHF (including those for direct satellite broadcasting use at frequencies above 1 GHz); 2 that the above studies should be completed by 2005; 3 that administrations be invited to provide appropriate measurements of VHF and UHF antenna radiation patterns (including those for direct satellite broadcasting use at frequencies above 1 GHz). _
