The Chair of IARU Region 1 Spectrum Affairs, Barry Lewis G4SJH, reports on the work being done in defending the interests of the Amateur Services in the 1240-1300 MHz band.

On the IARU Region 1 site he writes:

During the period May 4-10, 2022, the IARU continued to engage in the preparatory work for WRC-23 agenda item 9.1b in ITU‑R Working Party 4C (WP4C).

Work continued to develop the coexistence studies between the amateur services in the 23cm band and the radio-navigation satellite services (RNSS) operating across the band. New studies were submitted by France, China and the Russian Federation.

The scale of the problem for the amateur services is becoming clear. For example, the studies predict that even a 10W 23cm band station could cause interference to RNSS receivers at up to 30km on the antenna main beam heading. Although the level of amateur activity and the density of users is quite low (compared to other more popular bands) the issue remains that from a regulatory perspective the amateur services are required to not cause harmful interference to RNSS services.

The figure shows a sample of one result from one study submitted into ITU‑R and further illustrates the scale of the problem. In this example a station using an 18dBi gain antenna is used for both narrow band and wideband (ATV) transmissions and a range of power levels. The protection criteria for the RNSS receivers differs for narrowband and wideband interfering signals. The figure shows the distances out from the amateur station where the RNSS protection criteria could be exceeded along the antenna main beam heading.

These results have been developed based the ITU‑R defined receiver protection level for the GALILEO RNSS. For the narrow band modes this is ‑134.5dBW and for the wideband modes is ‑140dBW/MHz. In addition, measurement campaigns have shown that an improvement in the compatibility potential can be seen if the amateur signals avoid the centre portion of the GALILEO receiver passband.

Of course the studies cannot take into account every possibility that might mitigate the problem (e.g clutter, terrain blocking etc.) but it is clear that the potential for interference is considerable.

The IARU is working hard to ensure that the amateur service can continue to develop in this band and allow all the amateur applications in use today to continue. However, given the heavy spectrum occupancy of the band by the various RNSS systems it is evident that proposals will come calling to restrict our ability to operate in certain parts of the band and at the power levels possible today. IARU is totally engaged in the discussion of these considerations and these will continue within ITU‑R (and other regional bodies).

The IARU summary report on the WP4C meeting can be found at
https://www.iaru.org/wp-content/uploads/2022/05/IARU-Report-from-WP4C_May-2022.docx

Link to the full draft study https://storage.iaru-r1.org/index.php/s/BtpxWjL7La7syr7

Source IARU Region 1 https://iaru-r1.org/

A joint paper by France, Lithuania, Malta, Slovenia and The Netherlands for the CEPT CPG meeting in Ankara, August 26-30, attacks the continued use by Radio Amateurs of our 1240-1300 MHz band.

This is the final CEPT CPG meeting in preparation for the ITU World Radiocommunication Conference 2019 (WRC-19) to be held in Sharm el-Sheikh, Egypt, October 28 to November 22. This conference will define the Agenda Items for WRC-23.

Paper AI10 – Proposal on AS-RNSS says:

Galileo is close to full operational capability and its E6 signals in the band 1260-1300 MHz will support new services such as the free-to-use Galileo High Accuracy Service, and also robust authentication, expected to be used by a variety of applications including autonomous vehicles and the Internet of Things (IoT).

Several cases of interference to Galileo E6 receivers from amateur service emissions have occurred in the recent past, sometimes at significant distance, and have taken several hours or even days to be eliminated. There is therefore a serious concern that as Galileo E6 receivers are deployed and used more widely, cases of interference from amateur stations will rapidly grow in number.

A WRC-23 agenda item is necessary to address this issue because:

1. Unregulated use of the band 1240-1300 MHz by the amateur service is a serious source of harmful interference to RNSS receivers. This is demonstrated by experience.

2. The number of Galileo receivers in 1260-1300 MHz will increase dramatically, and interference cases will multiply if not addressed timely.

3. Galileo and other RNSS systems will deploy at global scale, and interference scenario between amateur emissions and RNSS receivers include cross-border cases. The issue is therefore of international nature and is to be addressed in the ITU framework.

4. Galileo is a major European asset, and a decision at WRC-23 is essential to be compatible with the roadmap of deployment of Galileo receivers in this band.

Download Paper: AI10 – Proposal on AS-RNSS from
https://cept.org/ecc/groups/ecc/cpg/client/meeting-documents/?flid=10031

Also see the IARU paper: RNSS Proposal WRC-19 AI 10 at the same URL

Some background information is at
https://amsat-uk.org/2019/05/31/1240-1300-mhz-band-discussed-by-cept-wgfm-and-cpg-pta/

European Commission Joint Research Centre report written 2014 and published 2015 on Compatibility between Amateur Radio Services and Galileo in the 1260-1300 MHz Radio Frequency Band. It reports the effect of transmissions of 0.1, 1 and 15 watts EIRP on a Galileo receiver up to 10 km away – download PDF here

January 2006 – Potential Interference To Galileo From 23cm Band Operations by Peter Blair G3LTF
http://www.southgatearc.org/articles/galileo.htm