The Bromley and District Amateur Radio Society

Ofcom consultation to sell-off Amateur Satellite 10 GHz band
by Paul G1ROK

OFCOM are once again trying to sell off allocations that would affect satellite usage for the Ham Radio and non profit community, after the debacle of the pager frequencies being close to the WX sat frequencies you would have though that the authorities would have learned there lessons but alas no, This mindless pursuit of spectrum auctions and sod everyone else continues.

Ham Radio and non profit usage of these type of bands produce more of the technology that OFCOM want to sell than any government funded research program, when will they learn that we need innovation to make possible the technology and that innovation comes from experimentation, mostly by the very people OFCOM are trying to undermine.
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The 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.

Compare Ofcoms proposed protection levels with those specified by CEPT for Ultra Wide Band (UWB) where -85dBm/MHz is used as protection for valuable services

Secondary User

The consultation document says
A6.31 As use is on a secondary basis a future spectrum access licensee will not be obliged to protect the national Amateur use. Use by the Amateur Service on a national basis would only be permitted where the Amateur licensee could be confident of not causing interference to the spectrum access licensee.

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.

Poorly Researched

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 http://www.ofcom.org.uk/consult/ condocs/10ghz/spec_condoc.pdf

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 http://www.microwavers.org/files/10-40GHz-replysheet.doc

Responses should go to Joe.sonke@ofcom.org.uk and the deadline is 7 September 2006.

We would ask that All amateurs take the time to respond even if you are not directly involved with Microwave or Space comms, it is in all of our interests that an element of sense is restored to these processes.