There are two main action items at the moment. The first is the continuing struggle to preserve radio astronomy in the face of an active and well-run campaign by the satellite communications industry to minimize the concessions they have to make to radio astronomers while fighting for spectrum space for their new radio services. The second is the need for us to participate in the process of allocating bands above 70GHz. Up till now we have had a pretty free hand in the mm/sub-mm range. The communications industry now has uses for those bands, so over the next two or three years, allocations will be made in the band 70GHz-275GHz.
Dealing with the second issue first, you will remember our circulating around CASCA a request for input regarding the bands we should go after. Five people replied. I thought that the mm/sub-mm community in Canada was stronger than that! However, thanks largely to the efforts of Tom Gergely in the US and the members of IUCAF, a list of bands has been drafted. I added the (few) suggested changes, and passed it as our preferences to Industry Canada. The deadline for any last-minute suggestions is the 20th September. We will also be discussing this list of frequency allocations at the Working Group 7D meeting to be held in Geneva at the end of that month.
In an effort to squeeze more services (mainly those using satellites) into an already crowded spectrum, the national and international frequency managers have decided that a study be carried out for each band allocated to radio astronomy, to establish the type and extent of the protection required against interference by other services. A downside of this is that the communications industry will be able to focus on the needs of its services, and adopt a united, single-minded approach. The astronomy community is very different. People work more independently, and have more diverse interests. Moreover, radio astronomy is a research activity, so it is harder to define its needs in terms of protection against interference. All these points are fully appreciated by the satellite community, and they are being used against us. The satellite people have stated at a number of international meetings that they are fully up to speed on the band-by-band study, but they fear that the radio astronomers will not succeed in completing their obligations. We have no alternative to completing the work of the study. The future of radio astronomy depends upon it. As we proceed, we will need input. Please provide it.
The band-by-band study has been passed by the International Telecommunications Union to Task Group 1/5. In July a meeting of the task group was held in Munich. That meeting was very important to radio astronomy. Out of 133 delegates, about 38 were representatives of the satellite communications industry and FOUR were radio astronomers. The rest were various national spectrum managers. Once again the interest of the radio astronomy community was disappointingly limited. Two represented The Netherlands, one the United Kingdom, and the other Canada. This is really not very good. Besides putting the troops on the ground in difficulty keeping up with all the things happening at the meeting, it sends a very strong and unfavourable signal to the national and international spectrum managers.
One outcome of the meeting is that I am now a coordinator for the band-by-band study. I think this is a good move because we have in Industry Canada a national spectrum manager more sympathetic to radio astronomy than is the case in many other countries, and that in Canadian universities and the HIA we have enough expertise to push forward the core of work of the study. We will of course need full international cooperation, but we need not get bogged down as much with communications delays.
Here is the approach we in Canada are looking at. We put down a number representing the maximum tolerable percentage of data lost in an observing session due to interference (sorry, this is what all the other guys do, and zero, although very desirable, is not a realistic option). For the kind of observations we do, and the equipment we use to do them, this translates into a specification for the allowable intensity and temporal distribution of the interference. If our needs don't collide with the satellite industry's suggestion as to what is practical, then there will be no problem in establishing rules for co-existing in the spectrum. However, if we need more than they expect to provide, negotiation has to begin. Expect a lot of that.
In the past we didn't design radio astronomical hardware and software with interference in mind. Equipment improvements can greatly reduce the effect of interference on our data. For example, development of antennas with lower sidelobes, more selective receivers with larger, linear dynamic ranges, and spectrometers with large dynamic ranges, more amplitude resolution and more flexible programming. However, developing that technology will cost money. Since the development of such technology would benefit astronomers and industry, we are considering the possibility of industrial partnerships to develop it.
The next meeting is in Geneva at the end of September. Before that radio astronomers will be getting together at IRAM to discuss plans, and maybe talk some science. We will be providing input on the protection of the 406-410 MHz band, which is threatened by allocation of the band immediately below to mobile satellite services, and to provide a document on frequency sharing in the 1.6GHz (OH) bands. Industry Canada agrees with us in refusing to support any satellite programme likely to affect observations in the 1400-1427 MHz band. These meetings are not fun, but they are sort of educational, in a masochistic sort of way. As management of the radio spectrum becomes more and more commercially oriented, we must broaden our activities beyond participation in the standard frequency management process. We need to take our problems into a broader forum. Radio astronomy by itself has little public understanding. However, presenting our case together with the issues of light pollution and space junk as unnecessary environmental pollution could be important. If we allow the guys with the most troops and the biggest guns to choose the battlefield, the results will be easy to predict.
Ken Tapping <Ken.Tapping@hia.nrc.ca>
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