23cm Band and RNSS Coexistence September Update

RNSS Satellites Oribiting EarthAs the WRC-23 approaches so the studies regarding AI9.1b (23cm and RNSS) are working towards conclusions. However the IARU is not content that all the operational aspects of the amateur service usage of the 1240-1300 MHz band are being properly considered to develop an acceptable compromise for all concerned parties.

Having been deeply involved in the regulatory work described below it is the opinion of the IARU that for many national authorities the 23cm band WRC23 agenda item 9.1b topic has a very low priority. Many are taking a “generic” stance stating their support for studies without considering the detail of the work or how it is moving forward. Therefore the IARU requests that Member Societies urgently put this issue on the agenda with their national authorities to discuss the views laid out below.

The IARU view is that the potential for widespread or persistent interference to the radio-navigation satellite service (RNSS) from amateur service transmitters is over-stated. However, recognising the regulatory situation, the IARU and the amateur community are ready to accommodate any technical or operational measures deemed necessary on the amateur services so long as they are proportionate, reasonable and evidence based.

The IARU believes that a careful compromise needs to be found in the outcome of the work and the execution of WRC-23 agenda item 9.1b, that properly takes account of the low likelihood of interference events occurring whilst allowing both the amateur services and the RNSS to develop in the band.

The IARU stresses the opportunity that the higher frequency amateur service bands enable for technical skills development for researching and experiencing radio propagation effects. The 1240 – 1300 MHz band is important for the amateur radio service, being the lowest allocation for radio amateurs on which typical microwave propagation can be experienced. Access to these frequencies is facilitated by commercially available equipment and provides a ‘bridge’ building motivation to become involved in more specialized higher frequency microwave and millimeter wave operations providing the self-training which is at the heart of amateur radio.

Read the paper IARU Perspective on the AI9.1b Progress — September 2022
https://www.iaru.org/wp-content/uploads/2022/09/Sept22-23cm-RNSS-Update-.pdf

Source IARU 23cm Band and RNSS Coexistence
https://www.iaru.org/spectrum/iaru-and-itu/wrc-23/agenda-item-9-1-topic-b/23cm-band-and-rnss-coexistence/

EU WRC23 agenda items consultation and RNSS/23cm band study

The Chair of IARU Region 1 Spectrum and Regulatory Liaison Committee, Barry Lewis G4SJH, reports on the response to the EU WRC-23 consultation and the CEPT RNSS/23cm band study.

On the IARU-R1 site he writes:

In a collaboration between the IARU-R1 Spectrum and Regulatory Liaison Committee (SRLC) and the Political Relations Committee (PRC) an IARU Region 1 response has been provided to the European Union consultation on the WRC23 agenda items.

All the agenda items of interest to the IARU are covered with particular attention paid to the AI9.1b issue on the GALILEO / 23cm band amateur service coexistence. This is an important messaging activity and the IARU response again underlines the IARU view that with only two cases of interference recorded globally, the potential for interference is being over-stated and that any regulatory solutions should be proportionate, realistic and appropriate and should not hinder the future development of amateur services. The IARU would be pleased if member societies could share these same views with their national regulators.

The full IARU R1 response can be found at
https://www.iaru-r1.org/wp-content/uploads/2022/07/Response-to-EU-WRC23-Consultation_submitted.pdf

The PRC/SRLC is also developing a response to the European Commission Radio Spectrum Policy Group (RSPG) on the same topics.

Secondly the CEPT project team SE40 that is carrying out the CEPT studies on the RNSS/23cm band topic met during the week 25 – 28th July 2022. The IARU provided a contribution and participated in the meeting supported by USKA. Good progress was made but further work continues to be required to finalise the conclusions from the studies. The IARU continues to be concerned about the lack of consideration being given to the low probability of interference and more work is needed on this aspect. A summary report can be found at
https://www.iaru-r1.org/wp-content/uploads/2022/07/IARU-Report_SE40_77.pdf

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

Amateur/RNSS Coexistence – 23cm Band

After review and approval by the IARU Region 1 Executive Committee and the IARU Administrative Council a presentation on preliminary Amateur / RNSS Coexistence in the 23cm band has been released.

See the presentation at
https://www.iaru.org/wp-content/uploads/2022/06/23cm-Band-and-RNSS-June2022.pdf

Source IARU
https://www.iaru.org/wp-content/uploads/2022/06/23cm-Band-and-RNSS-June2022.pdf

1240-1300 MHz: ITU-R WP5A Meeting Report

Galileo LogoIARU report on the recent meeting of ITU-R WP5A, the lead group responsible for developing the Conference Preparatory Meeting report about the WRC23 agenda item on the 23cm band.

The latest meeting of ITU-R WP5A concluded on June 2, 2022. The IARU was represented by Ole Garpstad (LA2RR – ITU Lead) and Barry Lewis (G4SJH – WRC23 AI9.1b Lead).

ITU-R WP5A is the study group at ITU which deals in part with topics related to the amateur and amateur satellite services. It is the lead group responsible for developing the Conference Preparatory Meeting (CPM) report on agenda item 9.1(b).

This Agenda Item provides for a “Review of the amateur service and the amateur-satellite service allocations in the frequency band 1240‑1300 MHz to determine if additional measures are required to ensure protection of the radionavigation-satellite (space-to-Earth) service operating in the same band in accordance with Resolution 774 (WRC‑19);” The CPM Report will form the basis for consideration of this issue at WRC-23 next year.

At the conclusion of the recent WP5A meeting a draft recommendation was prepared which will provide guidelines to administrations to ensure the protection of the RNSS primary allocation from the secondary amateur and amateur satellite services.

The draft recommendation will be the most important element of the WP5A work going forward for the amateur and amateur satellite services in the 23cm band. The working document contains a number of proposals for severe limitations on amateur usage of the band including transmitter power constraints. Very low power levels are proposed for large portions of the band (100% in one case). Proposals also identify possible frequency band usage limitations for broadband applications (e.g. ATV), narrowband applications and amateur satellite services in 1260-1270 MHz.

A full report of the WP5A meeting can be found here.
https://www.iaru.org/wp-content/uploads/2022/06/Report-from-WP5A_June-2022-FINAL.pdf

None of these proposals are adopted at this time and work will continue at the next meeting of WP5A to rationalise the variations proposed by national telecom-administrations.

The IARU will work to minimise the constraints on amateur radio activities and continue to seek amendments to the draft recommendations through the ITU process, but as a secondary user, radio amateurs should understand the need to protect the Radionavigation Satellite Service (RNSS) in many consumer and industry applications (like autonomous vehicles) that will lead to some restrictions on our use of the 23 cm band.

23cm band and Sat-Nav Coexistence: ITU‑R WP4C Studies

Galileo LogoThe 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.

RNSS Protection Criteria

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/

IARU-R1 papers on 23 cm band Amateur/RNSS coexistence

CEPT LogoCEPT SE40 meeting #76 being held April 11-13 is studying the issue of coexistence between amateur radio operation in 1240-1300 MHz and RNSS systems such as Galileo.

One of the Agenda Items for the World Radiocommunication Conference (WRC23) is AI-9.1b – Measures to be applied in the frequency band 1240-1300 MHz to ensure the protection of the radionavigation-satellite service (RNSS) in accordance with Resolution-774.

SE40 is the CEPT ECC working group that looks at Space Service compatibility issues.

IARU Region 1 has submitted these documents to the April meeting:
• Amateur density numbers
• Amateur density numbers Background
• Updated Proposals for WI_39 report

These papers and other meeting input documents can be downloaded from
https://cept.org/ecc/groups/ecc/wg-se/se-40/client/meeting-documents/?flid=30061