Radio Regulations

Source: the Radio Regulations published by the International Telecommunication Union (ITU).

WRC Agenda Item › WRC-27 › AI 1.2
AI

1.2

WRC-27 · Agenda item 1.2

to consider possible revisions of sharing conditions in the frequency band 13.75-14 GHz to allow the use of uplink fixed-satellite service earth stations with smaller antenna sizes, in accordance with Resolution 129 (WRC-23)

Current WP 4A Res. 129 (WRC-23) › 13.75–14 GHz
At a glance Summary & background Regulatory Studies

At a glance Beta

Frequency band
13.75–14 GHz
Governing resolution
Res. 129 (WRC-23)
Responsible group WP 4A
Agenda-item type Technical

The band and its sensitive neighbours

13.75–14.0 GHz Fixed satellite Radiolocation Earth exploration-satellite 13.25–13.75 SPACE RESEARCH 13.77–13.78 13.2 13.75 14.0 14.05 GHz
Fixed satellite
Radiolocation
Earth exploration-satellite
SPACE RESEARCH

Blocks group a service with its direction and mode variants; the table names each allocation as the Radio Regulations name it.

Current framework

Services in this band

FIXED-SATELLITE (Earth-to-space) Primary
Radiolocation Primary
Earth exploration-satellite Secondary
Standard frequency and time signal-satellite (Earth-to-space) Secondary
SPACE RESEARCH Secondary

Key figures in today's rules

Parameter GSO Non-GSO
Min. antenna diameter
 1.2 m 4.5 m
PFD at coast / border
for antennas below the diameter threshold
 ≤ −115 dB(W/m²·10 MHz)
Radar e.i.r.p. (RLS/RNS stations)
 ≤ 59 dBW (>2° elev.) / 65 dBW — unchanged
SRS mask 13.77–13.78
 ≤ 4.7·D + 28 dB(W/40 kHz)

Reference figures, verified against the Radio Regulations.

What's being studied — points to watch

Replace the size proxy

Revisit the minimum antenna size and its associated power limitations (Res. 129) — keep today's interference ceilings without the fixed-diameter proxy.

Non-GSO minimum size

The 4.5 m floor is the most consequential number for new constellations — the likeliest focus of debate.

Space-research mask

Re-express the 13.77–13.78 GHz e.i.r.p.-density mask for small antennas without weakening deep-space protection.

Coast & border PFD

Show smaller, higher-power terminals still meet the coastline and border limits that shield radar.

Radar that can't coordinate

Ship and mobile radiolocation stations cannot be notified under No. 11.14, so coordination cannot fix interference — hard limits carry the protection (Res. 129).

Preparation timeline

  1. Dec 2023 WRC-23 agenda adopted
  2. Dec 2023 CPM 27-1 studies allocated
  3. ITU-R studies 2026
  4. ITU-R studies 2027
  5. 5–15 Apr 2027 CPM 27-2 final report
  6. RTO Prep meetings 2027
  7. 11–15 Oct 2027 RA-27
  8. 18 Oct–12 Nov 2027 WRC-27

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Source: ITU Radio Regulations, editions of 2008, 2012, 2016, 2020 and 2024. The English, French and Spanish texts are each taken from the official edition in that language, not translated from one another. Sources and citation.