CBS/ISS Steering Group on Radio Frequency Coordination
Geneva, Switzerland
16-18 March 2006
Report by Bruce Sumner
18 March 2006

The WMO report of the meeting is currently awaiting extra information/input and will be available at: http://www.wmo.ch/web/www/CBS-Reports/ISS-index.html and also at http://www.wmo.ch/web/www/BAS/CBS-meetings.html

Participants
Markus Dreis, Eumetsat, Germany,
Roger Atkinson, Australia
James Mentzer, NOAA, USA
Bob Leck, USA
John Zuzek, NASA, USA
Dave Franc, USA
Giometti, Brazil
Jianguo Zhang, CMA, China
Bryan Hunycutt, JPL, USA
Franc Zichy, NOAA, USA
Phillippe Tristant, France
Bruce Sumner, HMEI
Jean-Michel Rainer, WMO Secretariat, Geneva

1.         ITU, under ITU SC7, has determined that it wants to collect information on all optical MetAids that are being used and manufactured . The optical band means in the THz band. This is to be just a list for information purposes, there are no thoughts about regulation. It’s just a list of sensors and instruments that operate in this band.

Action:
HMEI has been asked to assist in identifying the instruments and sensors that operate in this area. Here is the preliminary version as submitted to ITU SG7).

2.            Discussion on short-range devices in the 401-406 MHz band. A manufacturer of medical implants wants to have partial access to the 401-406 MHz band for medical implants. A preliminary recommendation by ITU is that each frequency agency in member countries licence such devises in their own country. The issue is that a patient is not affected by interference from a radiosonde.  Each medical manufacturer may be able to apply for a waiver not to have to comply with interference mitigation techniques. Only one glucose monitoring device has been given such a waiver in the USA, but other instruments will be making such application for a waiver in the near future. Met services have to very aware that if a person dies because of interference from a radiosonde, the Met service may be found to be responsible. It may be that part of this band may be lost to medical devices . The meeting concluded that regulation of this issue was required, as people now travel extensively around the world with such medical devices operating in the 401-406 MHz band. 

3.             UAV’s and drones.
The meeting discussed the need of these new instruments to possibly be given a radio-frequency band to be used for the downloading of data from these devises. However it is possible that satellite links could be used and thus  the radio-frequency bands would not be affected. It was stated that there are not many manufacturers in this technology yet, but a band may be need to be provided for there use.

4.         A recommendation on the 1675-1683 MHz band used by radiosondes  and met satellite ground stations, and how these two uses should be separated, is now going through the approval process in ITU.

5.         A review of the status of wind-profilers and meteorological radar recommendations was made. The four wind profiler recommendations are several years old and need updating.. ITU Working Party 8 is responsible for these recommendations, and they should be contacted with updates.

            There are also several recommendations regarding conventional Doppler Meteorological radars, but there are inconsistencies, particularly with regard to protection criteria; some recommendations specify a theoretical criteria of -14dB, others -10dB and yet others -6dB. The possibility of combining all the radar recommendations into one composite recommendation, with either a list of criteria, or a methodology to determine the criteria, was suggested. However the best solution was considered to have a recommendation that states both criteria and a methodology, as the characteristics required by one user may not be the same as another user, so sometimes definitive protection criteria may not be appropriate.

            There was a discussion that the interference criteria and the protection criteria should be set by the meteorological user community, and the manufacturers be asked to manufacture radars to these specifications.  It was felt that manufacturers would be responsive to this approach, as they would have specific user specifications to guide them in their development and ,manufacture process.

6.         A document has been prepared discussing the differences between meteorological radars and ordinary radars. This was prepared for general guidance at ITU so that everyone is able to know of the differences between the two radar requirements. However the document has some missing information, and other parts require some updating.

Action:
The Chairman asked HMEI if it would assist with this update, especially on the section on antennae patterns. Other parts needing updating are on the effects of interference and the various types of processing that can be incorporated in the radar processing to minimise the effects of interference.

7.         The 2700-2900 MHz band, used by airport surveillance radars and other met radars, was considered finalised by ITU and was not open to discussion.  However there is now a call to open up this band for use as a candidate band for use by IMT-2000 and IMT-Advanced mobile telecommunications. The consensus here was that it would be recommended that this band not be opened up for new usage.

8.         Of the 160 met radars in Europe, 140 operate in the 5600-5650 MHz band. This band has to be shared with RLAN devices. Interference from these devices happens up to 10km distance. It is proposed to that Dynamic Frequency Selection (DFS) be mandated as essential for all 5 GHz RLAN devices. This requirement will ensure proper protection of all met radars in the 5470-5750 MHz band. It was stated that some radars have become completely unusable because of interference from RLAN devices. An example is in Hungary, which has two weather radars to cover the entire country, and now one radar has become useless and now only half the country has weather radar coverage.

9.         The impact of wind turbines on weather radars was discussed. In France some radars have been blinded because of wind farms built near and around them. Turbines can affect radars up to 50 km distance. Precipitation amounts can be contaminated by nearby turbines. There seems to be a proliferation of these wind turbines, and in many countries their siting is not known to the meteorological community until after they are built. The meeting expressed extreme concern about this issue, but was unable to offer any solutions.

10.       There is an increasing requirement for met radars operating in the 3-30 MHz range for the monitoring of sea-state, including sea-surface winds. There apparently are other applications for RF radars, and the meeting stated that radar manufactures should be made aware of this growing requirement for such radars.

11.       Several papers discussed the need foe assessments studies of how various Earth Exploration-Satellite Service (EESS) passive sensors and other active sensors affect each other in various bands. It was stated that some preliminary assessment studies have already been made.

12.       There was considerable discussion on ground-based passive sensors. These are upward-pointing radiometers. There is experimentation with this technology and several such systems are under development.  Requirements have not yet been specified, nor have frequency bands been allocated. However it has been suggested that the Earth Exploration-Satellite Service (EESS) allocated passive spectrum bands could be used. The issue is more similar to those of radio astronomy than to sensors on satellites. There is a requirement for characteristics and definitions of this type of passive sensor to be specified, but it would be extremely difficult to introduce another technical and information document on yet another passive sensor to ITU. The meeting therefore decided just to ask ITU if these sensors would be added to the current EESS passive sensor area, without any mention of such things as protection criteria.

13.       The need for a general information document called something like ‘Spectrum Allocation Guide’ was discussed. This would be a document/brochure to give to people not aware of the met requirements for radio frequency allocation and protection. WMO said it would possible be able to fund the production of such a publication. It would include information of socio-economic considerations. It would help as a means to advocate the benefits of protection of met spectrum allocation. There was a discussion on possibly hiring a consultant with the right marketing/economic background to prepare this publication.  A first step would be the collection of the technical information, and it was stated that a start could be obtained by extracting the relevant information from NASA/NOAA publications, and also foro European passive spectrum guides.

14.       A draft document on the WMO position on World Radio-Communications Conference 2007 (WRC-2007) was presented. It is a very good overview, generally in non-technical language, of the WMO position on the various relevant agenda items of WRC-07.
A copy of this for HMEI member information is provided (Doc 7(1). 

Actions for HMEI:

1. Update the Optical MetAids report

2. Provide update to Met radar report

3. Be aware of WMO (and HMEI) action items for WRC-07