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Author: Barry, G4SJH

IARU Position on the Utilization of the 430 – 440 MHz Amateur Band by AST SpaceMobile Satellite Constellation
· Spectrum · Barry, G4SJH

The information that follows was posted on the IARU Global web site on July 18th:

AST & Science LLC (operating as AST SpaceMobile) currently deploys commercial satellites in Low Earth Orbit that utilize spectrum allocations within the 430 – 440 MHz amateur and amateur satellite bands for Telemetry, Tracking, and Command (TT&C) operations. The satellites, designated Bluebird 1 – 5, were launched on September 12, 2024, and function under an FCC Space Bureau authorization pursuant to Article 4.4 of the ITU Radio Regulations. This provision permits administrations to authorize stations using frequencies that are not in accordance with the ITU‑R Table of Frequency Allocations or other relevant regulations, provided such use does not cause harmful interference to other administrations authorising services that are in accordance with the Table of Frequency Allocations.

Bluebird satellites employ the following frequencies for TT&C operations with 50 kHz bandwidth utilizing Gaussian Frequency Shift Keying (GFSK 2400): 430.500 MHz, 432.300 MHz, 434.100 MHz, 435.900 MHz, and 439.500 MHz. Additionally, AST’s prototype satellite Bluewalker‑3 transmits telemetry on 437.500 MHz. These frequencies are not intended to carry the service user traffic, and the use of these UHF frequencies is proposed for exceptional circumstances when the normal Q and V Band TT&C channels are not useable (40 and 60 GHz bands).

In June 2025, the FCC Space Bureau accepted a further application from AST & Science LLC for the deployment of 243 additional satellites intended to use the 430 – 440 MHz spectrum for telemetry purposes.

Supporting material for the new application also suggests that use of the 430 – 440 MHz range by the new additional satellites may be limited as these are expected to use the S‑band (around 2 GHz) exclusively for TT&C when needed.

The 430 – 440 MHz band supports a range of amateur and amateur satellite applications, including weak-signal communications, space communications, digital television, data transmission, repeaters, and other uses. There is no specific sharing study considering the impact of the TT&C transmissions in the 430 – 440 MHz band on these amateur applications despite the Primary status of the amateur service allocation in Region 1 and 11 countries in Region 2.

The International Amateur Radio Union (IARU) and its member societies have expressed concerns regarding the lack of any technical assessment on the potential interference arising from AST satellite TT&C transmissions affecting the aforementioned applications. The IARU maintains that invoking Article 4.4 of the Radio Regulations is inappropriate in this context, given the considerable risk of interference associated with AST’s use of the amateur allocation.

To address these issues, the IARU has communicated its position in correspondence to the Director of the ITU Radiocommunications Bureau. IARU member societies are encouraged to engage their respective regulatory authorities about the implications of AST satellite TT&C transmissions within the 430 – 440 MHz band and to inform their members accordingly.

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CEPT ECC Decision (25)01 relating to the 23cm band published and in force.
· Spectrum · Barry, G4SJH

The CEPT ECC plenary meeting in June 2025 finalised and approved ECC Decision(25)01 that includes the technical and operational measures for the use of the frequency band 1258 – 1300 MHz by the amateur and amateur-satellite services in order to protect the radionavigation-satellite service (Galileo).

The Decision is now in force and the ECC plenary agreed that a preferred date for implementation shall be 27 December 2025. This is reflected in Decides 4 of the Decision.

Activity now passes to the individual CEPT administrations to decide how this Decision will be implemented in their country. The status of the national implementation can be found here in the CEPT ECC document database.

Additionally an IARU support paper is available here that provides background on the elements in Annex 1 of the Decision relating to the 23cm band.

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CEPT approves a draft Decision for 23cm band/Galileo RNSS coexistence
· Spectrum · Barry, G4SJH

CEPT WG-FM meeting # 109 held over the week 10 – 14th February approved a draft ECC Decision identifying the frequency bands for the European Galileo satellite navigation system and the operational measures for ongoing 23cm band usage in the range 1258 — 1300 MHz. The draft Decision (No. ECC DEC(25)01) is currently undergoing “member notification” until the 28th February followed by formal Public Consultation that will last for 6 weeks until 11th April. The draft as it stands is available here. With this procedure in mind it can be assumed that the final approval will take place at the end of June at which time the preferred date for implementation will be agreed.

A summary report covering this and some other activities in CEPT is available here.

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The 23cm band/RNSS story continues within the European CEPT region
· Spectrum · Barry, G4SJH

During the week before Christmas, CEPT project team FM44 finished their work on a draft ECC Decision to designate and harmonise the three GALILEO radio navigation satellite service bands including the E6 band 1258 to 1300 MHz. In this band the technical and operational constraints on the amateur and amateur satellite services are to be included for use by any CEPT regulators that decide to implement the Decision nationally. The technical measures are the same as those proposed in ITU‑R Recommendation M.2164 adopted at the end of 2023 just ahead of the WRC-23.

The draft ECC Decision will now go forward to the parent group WG-FM to be considered at the next plenary meeting in February and that meeting may adopt the draft for Public Consultation subject to there being no objections in the two week period following the meeting. The Public Consultation will follow and proceed for at least six weeks. Any comments received will be collated and provided to the project team FM44 for consideration so that a final draft can be provided to the parent WG-FM for their meeting in mid-June. Finally it will be adopted for publication at the CEPT top level (the ECC) and this could happen at their meeting scheduled for the end of June 2025. It is common for the regulators in that meeting who expect to implement a new Decision to identify their intention to do so. 

Then the relevant national procedures will follow.

IARU R1 continues to be actively engaged in the work in CEPT.

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Developing the amateur services in the 23cm band and ITU‑R Recommendation M.2164
· Spectrum · Barry, G4SJH

Certain administrations and regional telecommunications organisations are considering how to implement the outcome from the World Radio Conference WRC-23 and the ITU‑R Radio Assembly which approved and published ITU‑R Recommendation M.2164. This provides guidance on technical and operational measures to be applied to the amateur and amateur satellite services to protect the radio navigation satellite service (RNSS) in the 23cm band (1 240 – 1 300 MHz).

The measures detailed in the Recommendation if applied fully across the whole 1 240 – 1 300 MHz band would severely restrict certain amateur activities and especially the development of broadband applications. Today interesting developments and experiments are taking place with respect to data transmission, digital image transmission and data networking (e.g HamNet). The band is ideal for these purposes and unnecessary restrictions in certain parts of the band would certainly impede these developments.

Regulatory organisations are beginning to consult nationally on this issue and it is vital that the scope of any national or regional implementation of the M.2164 measures remains focussed only on the part of the band relevant for the RNSS system under consideration.

National societies are urged to engage in these national discussions and to aid understanding of the issue the IARU Region 1 Spectrum and Regulatory Liaison Committe (SRLC) has published a paper “Developing the amateur services in the 23cm band when considering ITU‑R Recommendation M.2164″ which can be consulted.

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