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www.southgatearc.org
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Ofcom launch consultation on plan to sell-off Amateur Satellite 10 GHz allocationThe United Kingdom regulator OFCOM has announced a consultation on its plans to sell off 10.475 to 10.500 GHz. This is the top half of the internationally agreed Amateur Radio Satellite Service 10 GHz allocation. This vital Amateur Satellite allocation at 10 GHz was recently used by the AO-40 satellite. Other Amateur satellites currently under construction such as the P3E and the Mars Orbiter will be using that segment. Interference Levels Ofcom envisage that a future commercial user would run up to 55dBW eirp in this band. Such transmissions would completely wipe out the weak satellite signals received by Amateurs. It is not just the top half of the Satellite allocation that would be affected. Ofcom propose the following protection for adjacent bands “43 + 10Log10(P) dB or -70dBc, whichever is the less stringent for out of band emissions where P is the output power applied to the transmission line - dBc refers to a level relative to the main carrier.” This is remarkably lax, for a 55dBW transmitter; out of band emissions
which could fall in the lower half of the Satellite allocation 10.450-10.475
GHz, would be 15dBm which is way above receiver noise floors. Amateurs
operate narrowband with receivers as good as -130dBm. Secondary User The consultation document says MoD is the Primary User and therefore other new users will also be Secondary.
Under the Radio Regulations there is little/no concept of one Secondary
having precedence over another Secondary. The document appears to be poorly researched, claiming in one place that 10.45-10.5 GHz is designated as only Space to Earth. This is incorrect, the allocation can be used for both Space to Earth and Earth to Space communications. This could mean Amateur ground stations running in excess of 55 dBW eirp in the 10.45-10.5 GHz segment that they propose to sell off. Page 80 of the consultation document references the AMSAT-NA web site. It tries to use it to claim that the Amateur Satellite Service does not utilise this allocation. Yet if they’d have looked more carefully at the web page they would have found a very recent Amateur Satellite used it and that other satellites currently being constructed will use it. Consultation Announcement The consultation announcement - Award of available spectrum: 10 GHz, 28 GHz, 32 GHz and 40 GHz can be seen at http://www.ofcom.org.uk/consult/condocs/10ghz/ The full consultation document is at Anyone can respond to the consultation - it is not restricted to UK nationals. It is not necessary to answer all the questions in the response form (page 6). A response to Question 1 that just related to 10 GHz would suffice. A preformatted reply sheet can be downloaded from Responses should go to Joe.sonke@ofcom.org.uk and the deadline is 7 September 2006.
P3E P5A Mars Orbiter AO-40 IARU Amateur Satellite Frequency Coordination
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