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

IARU-R1: 23cm Band and RNSS – Compromises need to be found

RNSS - Credit IARU Region 1

RNSS – Credit IARU Region 1

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:

As we head into 2022 the ITU‑R and CEPT work considering the 23cm band and coexistence with the RNSS systems (GALILEO, COMPASS, GLONASS, GPS…) will continue so where have we got to and where is it heading?

The IARU has provided extensive information regarding the amateur and amateur satellite service applications in the band 1240 – 1300MHz as well as operational characteristics and data indicating the density of active transmitting stations and the busiest periods when these are most likely to be operational. Using this data, one CEPT administration has provided an extensive set of propagation model predictions for a number of amateur operating scenario assumptions (including satellite working and EME operation) that predict an “interfered area” over which an amateur transmissions may be received by a RNSS receiver at levels exceeding a defined protection level. Another ITU‑R member administration contributed a smaller set of predictions using the same model. The received RNSS interference level that the RNSS can tolerate (receiver protection level) is based on ITU‑R recommended criteria and depends on whether narrowband or wideband interfering signals are being transmitted.

The propagation model predicts that an interfered area can extend out to several tens of km (depending on the scenario) but at the extremes of the area, the time probability of exceeding the protection level is very low (1%) and for only 50% of locations. The model can only assume a full power continuous transmission.

In addition much attention has been paid to documenting an interference case recorded in Italy between an Italian 23cm band repeater and GALILEO receivers at the nearby European Commission Joint Research Centre in Ispra where work is undertaken to develop and test GALILEO system applications. The impact of traffic through this very local repeater (12.5km distant) on three different GALILEO receivers has been documented. This work suggests that whilst RNSS receiver bandwidth can have a part to play in enabling coexistence, beyond that nothing has been reported that could help develop any coexistence criteria. Nothing is reported about the mode of failure in the receivers beyond degradation on C/N.

This one case is often cited as the “proof” that interference can occur.

At present the conclusions from this work are being developed (in ITU‑R and CEPT) and IARU work continues to ensure these results are put into a real world context to understand what they imply with respect to successful coexistence.

Amateur transmissions virtually anywhere in the band will be co-frequency with the RNSS receivers from one system or another. It is therefore obvious that any RNSS receiver will be open to any co-frequency amateur transmission and amateur operators have no way of knowing where or when a RNSS service user is active. Therefore IARU has expressed a view that for successful coexistence guidance to be developed, some compromises will need be necessary.

As we move through the work in 2022 we need these compromises will become apparent so that the amateur community can know how to respond appropriately in a way that can allow our diverse set of applications to continue to develop whilst minimising any potential disruption to RNSS services. It is anticipated that the international views on the ITU‑R studies will need to stabilise by the middle of this this year in order to meet the timetable for the WRC-23 preparatory work. These views will likely propose technical and operational measures to be applied to the amateur and amateur satellite services that could be formalised in the Radio Regulations.

As the study activities work towards conclusions it is vital that the national societies engage with their national amateur radio regulators to ensure they understand and hear about the importance of this band for the amateur radio community.

Source IARU-R1

RNSS and Amateur Services

ITU-R: 23cm ham radio band and Sat-Nav Coexistence

Galileo LogoDuring the period October 20-29, 2021, the IARU continued to engage in the preparatory work for WRC-23 agenda item 9.1b in ITU‑R Working Party 4C (WP4C).

The IARU Region 1 reports says:

The working party is considering simulations provided by two administrations to estimate the interfered area that might exist around a 23cm band amateur service transmitter. A number of amateur station configurations are under consideration identified as “Home Station 1”, “Home Station 2” and “Permanent Station” (e.g. Repeater station) based on characteristics developed and contributed by the IARU. Both narrowband and wideband emissions are considered. Two further scenarios are included in which “Home Station 1” operates with antenna uptilt as an amateur satellite uplink station and in which “Home Station 2” operates with antenna uptilt as an E‑M-E station.

The IARU representatives contributed to an off-line email discussion to ensure the amateur station parameters used are more representative than those that had been proposed in the original contribution papers. The studies were revised based on these negotiations during the meeting and are reflected in the draft working document. The interim results show interference distances of up to several km depending on the antenna and power level assumed. Work on these studies will continue into the next meeting.

Other measurements campaigns are investigating the effect of offsetting the transmission frequency of various amateur signals with respect to the centre frequency of the RNSS signal and the impact of the RNSS receiver bandwidth.

The IARU is working to ensure the amateur services are realistically represented in the studies as they move forward and remain consistent with the information developed in WP5A. It remains vital that national amateur communities present their views on the importance of this band to their national regulators in a consolidated and consistent manner.

The work on this topic will continue throughout the year both in ITU‑R and in the regional telecommunications organisations and the IARU is committed to ensure every group hears the amateur position on this important microwave band.

The summary report from the WP4C meeting can be found here

Click to access Report-from-WP4C_Oct-2021.pdf

The parallel work in CEPT SE40 is tracking the activity in the ITU‑R and is at a similar stage of development. This is also within the purview of the R1 SRLC.

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

23cm band: Amateur radio coexistence with Sat-Nav

Galileo LogoThe Chair of IARU Region 1 Spectrum Affairs, Barry Lewis G4SJH, reports on the meeting of the ITU-R Working Party 4C (WP4C) July 5-13 which discussed the amateur radio 1240 MHz band.

On the IARU-R1 site he writes:

During the period 5 – 13 July 2021, the preparatory work for WRC-23 agenda item 9.1b continued in ITU‑R Working Party 4C (WP4C). (See Region 1 Feb 23rd news item for further background). The IARU member representatives from Australia, Brazil, Canada, Germany, Japan, Norway, UK and USA, participated in the meeting and delivered additional information on amateur activities in this key microwave band

Preliminary studies came from France based on the ongoing CEPT work to provide initial estimates of separation distances required between RNSS GALILEO receivers and a sample of amateur emissions. The European Commission GALILEO team provided a set of observations pertaining to a RNSS interference event in northern Italy.

The work contributed by France, although needing refinement, is going in a good direction, using ITU‑R recommended propagation models and assumptions based on operating scenarios provided by the amateur community. Further work is needed to take account of the large disparity between the RNSS service receiver bandwidths and the frequency band offsets of the amateur applications based on the measurements carried out by Germany.

The RNSS community have updated their RNSS receiver protection criteria with an update to ITU‑R Recommendation M.1902 that now includes parameters relevant to the GALILEO E6 signal block. However these criteria only distinguish between a narrow band and wide band interferer level at the receiver and take no account of offset frequency in the receiver bandwidth or any time variance.

The IARU is working to ensure the amateur services are realistically represented in the studies as they move forward. It remains vital that national amateur communities present their views on the importance of this band to their national regulators in a consolidated and consistent manner. The work will continue throughout the year and beyond both in ITU‑R and in the regional telecommunications organisations and the IARU is committed to ensure every group hears the amateur position on this important microwave band.

Read Barry’s full post at

Read the IARU Summary Meeting Report at

Recent activity on the 23cm band RNSS Coexistence Studies

CEPT 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.

His IARU Region 1 post reads:

IARU is continuing to represent the amateur services interests in the 23cm band Galileo/GLONASS radio navigation satellite service coexistence discussions in the CEPT project teams.

The most recent CEPT SE40 project team meeting was held from 24th to 26th March 2021 and the IARU R1 was represented by Barry Lewis, G4SJH (Region 1 SRLC chair). At that meeting the first coexistence calculations were introduced by one CEPT administration, based on some initial assumptions about the amateur service operation. The IARU is continuing to work with the regulators to refine the details of these assumptions and make them and the calculations more representative of typical amateur station characteristics and band usage. These first calculations are considered only as a starting point and the meeting agreed that further work is needed to develop the calculations into a more comprehensive study.

Measurement campaigns have shown that the potential for coexistence depends very much on the frequency of the amateur service transmissions in the 23cm band with respect to the RNSS receiver bandwidth. This aspect needs to be considered more carefully once the initial scenarios and calculations are agreed.

In addition the IARU continues to have questions about the protection criteria required by the RNSS receivers and in particular how they relate to RNSS operational and service provision behaviour. IARU has ensured alignment of the amateur and amateur service information being used in CEPT with that being used in the parallel work in the ITU‑R relating to WRC-23 AI 9.1b.

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

The meeting Input paper “Amateur versus RNSS, interference areas” that was submitted by France as well as other meeting documents can be downloaded from

1240-1300 MHz discussed at CEPT SE 40 meeting

CEPT LogoThe 69th meeting of CEPT ECC Working Group SE-40, held June 23-25, discussed the amateur radio 1240-1300 MHz band, the meeting documents are now available.

Several contributions were received for the ECC Report dealing with the coexistence between the radionavigation-satellite service and the amateur service in the frequency band 1240 – 1300 MHz. The contributions were incorporated in the draft ECC Report. The CPG arrangements for the preparation of WRC-23 for AI 9.1 topic b) was noted.

The Russian Federation noted:
1240-1260 MHz is by the GLONASS system
1260-1300 MHz are used by EU’s Galileo, Beijing’s Beidou, Japan’s QZSS and is planned to be used by Korea’s KPS.

Among the documents available in Input, Info and Minutes are:
• SE40(20)052 Amateur Repeaters – IARU-R1
• SE40(20)051 Section 2 update WI_39 – IARU-R1
• SE40(20)050 Annex Draft report RNSS Amateur – Russian Federation
• SE40(20)049 Suggestions for RNSS and Amateur Service Compatibility – Russian Federation
• Info 1 Amateur repeaters 23 cm – IARU-R1
• Info 3 Letter to SE40 chairman on updated of ITU-R M.1092 – European Commission
• Minutes
• SE40(20)56A3 (1) Draft Report Amateur vs RNSS

Download the meeting documents from