Protecting the spectrum

Many people are aware of the problem that light pollution causes for astronomers. What most people are unaware of is the growing threat to radio astronomy from radio pollution. By radio pollution I mean interfering signals from devices such as mobile phones, TV, CCTV, internet over power lines, wifi, microwave ovens etc. With the attraction to the UK government of selling the radio spectrum, and future technologies such as Ultra-Wide Band (UWB), this problem will only get worse (and could be a problem for others too). This is especially true in the UK where there just isn't space to set aside 13,000 square miles of countryside as a radio quiet zone like they do at the Greenbank Telescope in the US.

I've talked about the threats of UWB before. I've only just noticed that the government Office of Communications (Ofcom) website now contains a 2005 report on the impact of UWB (PDF) on radio astronomy. It reports on a study of the likely impact of UWB on astronomical observations with single radio dishes and with interferometer networks such as MERLIN. There were six responses quoted in the Ofcom consultation document. Five large companies with an interest in UWB technology (Freescale semiconductors, Intel, Texas Instruments, Thales and Philips) all, unsurprisingly, claimed that there wouldn't be a problem.

The report suggests ways for radio astronomers to cope with UWB. These include: a more controlled specification for UWB transmissions (good for astronomers but slightly more effort for the big companies), building huge fencing around radio telescopes (totally impractical and expensive), observing at night (reducing the ability to participate in international observations and observe transient objects) to hugely expensive and ridiculous ideas such as suggesting that current radio telescopes be moved a long way from populated areas (future radio telescopes will be a long way from civilization). The last response was from the UK radio astronomy community (including the late Jim Cohen no doubt) and the Royal Astronomical Society and nicely summaries by saying:

The suggestion of relocation of [radio astronomical] facilities is not realistic as the cost will be in excess of £100M. The suggestion of perimeter fences is also not realistic given that there are 6 sites to be protected to distances of the order of 10 km. The suggestion of restricting observations to periods of low activity will devalue the scientific programmes, which are undertaken 24 hr per day and 7 days a week. There is no understanding of the diversity of radioastronomy techniques, not all of which involve time averaging over long periods.



So what will happen? I suspect that big commercial interests may win in the end. Personally, I would prefer the narrow radio astronomy bands to be protected for passive use by anyone. I see this as equivalent to the way that we protect certain areas of our countryside as national parks for the quiet enjoyment of all.

Posted in astro blog by Stuart on Wednesday 21st Feb 2007 (01:00 CET) | Permalink
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