📡
Frequency
1681 MHz
Frequency
1681 MHz
🧭
Range
1675–1695 MHz
Range
1675–1695 MHz
🧩
Band Group
L-Band MetSat/MetAids
Band Group
L-Band MetSat/MetAids
🌐 Summary
The 1681 MHz allocation is part of the L-Band MetSat/MetAids spectrum. This range is used worldwide for critical applications that keep our communications and infrastructure running smoothly. On this page we highlight how each band is applied in real systems, from regulatory assignments to everyday devices. Our goal is to make spectrum data clear and practical for engineers, regulators, and enthusiasts alike.
Key uses of this band include: 1681 MHz is part of the meteorological‑satellite downlink segment used to deliver weather imagery and environmental data. Signals are space‑to‑Earth and must protect adjacent Radio Astronomy and mobile‑satellite allocations..
Core band; critical for global PNT services.
🔍 Explore the full RF Spectrum database
📡 Band & Geometry key
| Field | Value |
|---|---|
| Wavelength (m) | 0.17834173587151 |
| Waveforms | BPSK(1), BOC(1,1), MBOC – per system specs |
| Antenna Form Factor (Typical) | Passive or active patch (25–35 mm), helical, or chip antenna tuned for ~1575 MHz. |
| Band Family | L‑Band MSS Downlink (1626.5–1660.5 MHz) |
| Band | L‑Band |
| Primary Common Name | Weather satellite downlink (MetSat) / MetAids (radiosonde) |
| FSPL @ 1 km [dB] | 96.3 |
| FSPL @ 10 km [dB] | 116.3 |
| Fresnel Radius @ 1 km (m) | 0.211 |
| Band Group | L-Band MetSat/MetAids |
| Tax Band Family | L‑Band |
| Tax Band Class | 1675 MHz – 1699 MHz L-Band Meteorological Satellite Downlink (Mobitex) |
🧩 Applications & Usage
| Field | Value |
|---|---|
| Primary Application | Meteorological satellite downlink (weather & atmospheric data) |
| Lower Neighbor Use | RAS below 1668.4 MHz; MSS DL below 1660.5 MHz |
| Upper Neighbor Use | MetSat and adjacent regional allocations above 1695 MHz |
| Typical Services Devices | receivers, timing modules, IoT location devices |
| Market Common Devices | Satellite phones, gateways, IoT receivers |
| Refarming Use | Not applicable – protected band |
| Device Ecosystem Size | Specialized (government/agency/meteorology) |
| Device Hotspots (MHz) | Fixed meteorological satellite ground stations, national weather agency facilities, radiosonde launch sites, and research institutions. No consumer, mobile, or mass‑market device hotspots. |
| Device Category | Consumer, automotive, aviation, maritime, IoT, military receivers |
| Typical Use Cases | Positioning, , timing (PNT) for civilian and military systems |
| Modulation (Device) | Spread‑spectrum DSSS/BOC family: C/A (BPSK(1) 1.023 Mcps), (CBOC/MBOC), G1 (BPSK/FM‑CDMA), B1 (BPSK(2)/BOC). |
| Channel Width (Device) [kHz] | ~2000–4000 kHz main‑lobe equivalent (receiver bandwidths vary 2–24 MHz by design) |
| Device Region Profiles | Global profile; multi‑ (, , , ) enabled by default. |
| Per-Region EIRP Or Duty (Device) | N/A – receivers only; no transmit EIRP or duty cycle. |
| Allocation Relevance (Device) | Critical: allocation defines protected receive‑only operation; devices must meet susceptibility thresholds. |
| Adjacent-Band Collision Risks (Device) | High risk from adjacent MSS (≤1559 MHz) and out‑of‑band cellular/ISM emitters; use SAW/ceramic filters, LNA linearity, and tight front‑end selectivity. |
| Example Devices Or Skus | Ground station receivers; weather satellite downlink equipment; radiosonde receivers |
| Common Protocols | Proprietary MSS air interfaces (Iridium, Globalstar) |
🗒️ Notes
| Field | Value |
|---|---|
| Receiver Selectivity Notes | High selectivity (≥60 dB rejection across MHz) |
| Interference Notes | Protect adjacent passive Radio Astronomy below 1668.4–1668.7 MHz (RAS). Control adjacent-band emissions and out-of-band spurious. Coordinate satellite downlinks and ground reception sites; avoid high-power terrestrial emissions. |
| Compatibility Risk Notes | 0 |
| Notes | Core band; critical for global PNT services. |
| Propagation Notes | Free-space propagation dominated; global satellite visibility required |
⚙️ Technical Rules
| Field | Value |
|---|---|
| Lower Band Frequency Limit | 1675 |
| Upper Band Frequency Limit | 1695 |
| EIRP Indoor Limits | Not applicable – receive-only band |
| EIRP Outdoor Limits | Not applicable – receive-only band |
| PSD Limit | Not applicable – receive-only band |
| Emission Mask Class | N/A (Satellite downlink / agency reception) |
| Guardband Minimum [kHz] | N/A – receive-only band |
| Typical Bandwidths | 12.5 kHz–5 MHz (system‑dependent) |
| Autocalculated Bandlimits | 0 |
| Typical Bandwidths (Estimated) | 12.5 kHz–5 MHz (system‑dependent) |
| Max EIRP [dBm] | N/A – receivers only; no transmit EIRP or duty cycle. |
| Power Source Or Duty Profile (Typical) | Receiver‑side only; duty driven by application (tracking vs. timing holdover). |
| Channelization Plan | N/A (Satellite downlink / agency reception) |
| Channelization | N/A (Satellite downlink / agency reception) |
| Guard Band Requirement | N/A (Satellite downlink / agency reception) |
| OOB Emission Limit [dBm/MHz] | Strict OOBE < –60 dBm/MHz to protect adjacent channels |
| Spurious Emission Limit (dBm) | ≤ −60 dBm/MHz (strict protection standard) |
| RX Blocking Min [dBm] | N/A – passive receiver |
| Duplexing | Downlink (space‑to‑Earth) |
| Duplexing Information | Downlink (space‑to‑Earth) |
| Uplink Pairing | Not applicable – unpaired downlink only (space-to-Earth) |
| Downlink Pairing | Not applicable – unpaired downlink only (space-to-Earth) |
| Paired Band Info | Not applicable – receive-only band |
| Max EIRP [dBm] | N/A – receive-only band |
| Channelization Block Size | Operator carriers (kHz–MHz) |
| 3GPP Band Number | |
| Example 3GPP Bands | Not applicable – no 3GPP/LTE/NR band association |
| LTE Uplink Bands | Not applicable – no 3GPP/LTE/NR band association |
| LTE Downlink Bands | Not applicable – no 3GPP/LTE/NR band association |
| NR Uplink Bands | Not applicable – no 3GPP/LTE/NR band association |
| NR Downlink Bands | Not applicable – no 3GPP/LTE/NR band association |
| Guard Bands | N/A (Satellite downlink / agency reception) |
| Protocol Or Standard | ICD-200, OS SIS ICD, ICD, ICD |
🌎 Country Overrides
| Field | Value |
|---|---|
| Tax Service Category | Earth Observation / Weather Satellite |
| Tax License Type | Licensed / coordinated (region‑specific) |
| Tax Regions | Global (ITU Regions 1–3) |
| ITU Region 1 (Europe, Africa, Middle East (west of Persian Gulf), Western Russia & Mongolia) | Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth); Earth exploration-satellite (space-to-Earth) |
| ITU Region 2 (North America, South America, Central America, Caribbean, Greenland, Eastern Pacific Islands (Americas region)) | Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth); Earth exploration-satellite (space-to-Earth) |
| ITU Region 3 (Asia, Australia, Pacific Islands, Oceania, Indian Subcontinent, East Asia & Southeast Asia) | Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth); Earth exploration-satellite (space-to-Earth) |
| License Type | Licensed / coordinated (region‑specific) |
| Primary Application | Meteorological satellite downlink (weather & atmospheric data) |
| Primary Services | Meteorological data dissemination; environmental monitoring |
| Spurious Emission [dBm] | ≤ −60 dBm/MHz (strict protection standard) |
| Lower Neighbor Use | RAS below 1668.4 MHz; MSS DL below 1660.5 MHz |
| Upper Neighbor Use | MetSat and adjacent regional allocations above 1695 MHz |
| Licensing Model | ITU‑coordinated; operator licenses |
| Typical Services Devices | receivers, timing modules, IoT location devices |
| US FCC Alloc | Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth)– |
| CA IC Alloc | Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth)– |
| UK Ofcom Alloc | Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth)– |
| US Ref | ITU‑R M.1902 / M.2012 – performance standards |
| Typical Bandwidths | 12.5 kHz–5 MHz (system‑dependent) |
| Market Licensing Model | Licensed spectrum – coordinated via ITU / satellite operator agreements |
| Market Common Devices | Satellite phones, gateways, IoT receivers |
| Fresnel Radius (1st, 1 km) [m] | 0.211 |
| Typical Bandwidths (Estimated) | 12.5 kHz–5 MHz (system‑dependent) |
| Auction Status | N/A (Satellite downlink / agency reception) |
| Refarming Use | Not applicable – protected band |
| Typical Site Spacing km | N/A – space segment with global footprint. / N/A – space segment with global footprint. |
| Device Ecosystem Size | Specialized (government/agency/meteorology) |
| Traffic Load Share | N/A – receive-only service |
| Device Hotspots (MHz) | Fixed meteorological satellite ground stations, national weather agency facilities, radiosonde launch sites, and research institutions. No consumer, mobile, or mass‑market device hotspots. |
| Device Category | Consumer, automotive, aviation, maritime, IoT, military receivers |
| Typical Use Cases | Positioning, , timing (PNT) for civilian and military systems |
| Typical Center Frequencies [MHz] | N/A (Mission-specific; no standardized channel plan) |
| Rule Part (Fcc Or Region) | International: ITU‑R Radio Regulations (, space‑to‑Earth); National tables allocate ; receivers typically Part 15 (unintentional). |
| Modulation (Device) | Spread‑spectrum DSSS/BOC family: C/A (BPSK(1) 1.023 Mcps), (CBOC/MBOC), G1 (BPSK/FM‑CDMA), B1 (BPSK(2)/BOC). |
| Channel Width (Device) [kHz] | ~2000–4000 kHz main‑lobe equivalent (receiver bandwidths vary 2–24 MHz by design) |
| Device Region Profiles | Global profile; multi‑ (, , , ) enabled by default. |
| Per-Region EIRP Or Duty (Device) | N/A – receivers only; no transmit EIRP or duty cycle. |
| Allocation Relevance (Device) | Critical: allocation defines protected receive‑only operation; devices must meet susceptibility thresholds. |
| Adjacent-Band Collision Risks (Device) | High risk from adjacent MSS (≤1559 MHz) and out‑of‑band cellular/ISM emitters; use SAW/ceramic filters, LNA linearity, and tight front‑end selectivity. |
| Example Devices Or Skus | Ground station receivers; weather satellite downlink equipment; radiosonde receivers |
| Antenna Form Factor (Typical) | Passive or active patch (25–35 mm), helical, or chip antenna tuned for ~1575 MHz. |
| Power Source Or Duty Profile (Typical) | Receiver‑side only; duty driven by application (tracking vs. timing holdover). |
🛡️ Regulatory & Neighbors
| Field | Value |
|---|---|
| Lower Band Frequency Limit | 1675 |
| Upper Band Frequency Limit | 1695 |
| Rx Blocking Min dBm | N/A – passive receiver |
| Lower Neighbor Use | RAS below 1668.4 MHz; MSS DL below 1660.5 MHz |
| Upper Neighbor Use | MetSat and adjacent regional allocations above 1695 MHz |
| Lower Neighbor Band | RAS / MSS |
| Lower Neighbor Range | 1660.5–1668.4 / 1626.5–1660.5 MHz |
| Upper Neighbor Label | MetSat / regional (varies) |
| Upper Neighbor Range | 1695–1710 MHz (MetSat in many regions) |
| Adjacent-Band Collision Risks (Device) | High risk from adjacent MSS (≤1559 MHz) and out‑of‑band cellular/ISM emitters; use SAW/ceramic filters, LNA linearity, and tight front‑end selectivity. |
| Real-World Range (Indoor/Outdoor) | Outdoor sky view: global coverage; indoor: limited – assisted or repeaters required. |
| US FCC Alloc | Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth)Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth) |
| CA IC Alloc | Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth)Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth) |
| UK Ofcom Alloc | Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth)Meteorological aids (radiosonde); Meteorological-satellite (space-to-Earth) |
| Regulatory References | US: ITU‑R M.1902 / M.2012 – performance standards; CA: ITU‑R M.1902 / M.2012 – performance standards; UK: ITU‑R M.1902 / M.2012 – performance standards |
| Global Harmonization | Harmonized internationally (ITU Regions 1–3) for MetSat/MetAids |
| Crossborder Coordination | N/A (Satellite downlink / agency reception) |
| Sharing Mechanism | Passive coexistence only; no active sharing permitted |
| Auction Status | N/A (Satellite downlink / agency reception) |
| Guard Or Pair | N/A (Satellite downlink / agency reception) |
📈 Market & Measurements
| Field | Value |
|---|---|
| Noise Floor | Satellite downlink (space-to-Earth); GEO/MEO/LEO systems |
| Interference Cases | Protect adjacent passive Radio Astronomy below 1668.4–1668.7 MHz (RAS). Control adjacent-band emissions and out-of-band spurious. Coordinate satellite downlinks and ground reception sites; avoid high-power terrestrial emissions. |
| Lower Neighbor Range | 1660.5–1668.4 / 1626.5–1660.5 MHz |
| Upper Neighbor Range | 1695–1710 MHz (MetSat in many regions) |
| Interference Notes | Protect adjacent passive Radio Astronomy below 1668.4–1668.7 MHz (RAS). Control adjacent-band emissions and out-of-band spurious. Coordinate satellite downlinks and ground reception sites; avoid high-power terrestrial emissions. |
| Market Licensing Model | Licensed spectrum – coordinated via ITU / satellite operator agreements |
| Market Commercial Value | High – ubiquitous receiver ecosystem; critical PNT infrastructure |
| Market Common Devices | Satellite phones, gateways, IoT receivers |
| Market Deployment Density | Medium – global satellite coverage |
| Noise Floor (Estimated) | Satellite downlink (space-to-Earth); GEO/MEO/LEO systems |
| Market Commercial Value (Estimated) | High – ubiquitous receiver ecosystem; critical PNT infrastructure |
| Ecosystem Maturity | Fully mature global ecosystem (>10B receivers) |
| Indoor Penetration | N/A (Satellite downlink / agency reception) |
| Known Interference | Protect adjacent passive Radio Astronomy below 1668.4–1668.7 MHz (RAS). Control adjacent-band emissions and out-of-band spurious. Coordinate satellite downlinks and ground reception sites; avoid high-power terrestrial emissions. |
| Device Ecosystem Size | Specialized (government/agency/meteorology) |
| Real-World Range (Indoor/Outdoor) | Outdoor sky view: global coverage; indoor: limited – assisted or repeaters required. |
| Antenna Form Factor (Typical) | Passive or active patch (25–35 mm), helical, or chip antenna tuned for ~1575 MHz. |
| Ecosystem Maturity | Fully mature global ecosystem (>10B receivers) |
| Device Ecosystem Size | Specialized (government/agency/meteorology) |
| Chipset Availability | N/A (not a consumer /cellular chipset band) |
| Operator Deployments | Global constellation operators (US, EU, Russia, China, Japan, India) |
| Technology Generations Deployed | C/A, OS, G1, B1I/B1C |
| Roaming Support | Universal cross-system compatibility via multi- receivers |
| Traffic Load Share | N/A – receive-only service |
| Indoor Penetration | N/A (Satellite downlink / agency reception) |
| Known Interference | Protect adjacent passive Radio Astronomy below 1668.4–1668.7 MHz (RAS). Control adjacent-band emissions and out-of-band spurious. Coordinate satellite downlinks and ground reception sites; avoid high-power terrestrial emissions. |
| Occupancy | >95% utilization – global receivers |
| Occupancy Bucket Pct | >95% global utilization ( receivers ubiquitous) |
| Latency Profile | Deterministic; satellite signal propagation delay ~67 ms (20,200 km) |
| Common Channels Or Profiles | N/A (Satellite downlink / agency reception) |
| Security Features | Civil signals: message authentication ( OSNMA), multi‑ cross‑checks; Military: encrypted P(Y)/M‑code (not publicly specified). |
| Lbt Or Fhss Requirement | N/A (Satellite downlink / agency reception) |
| Popularity (Installed Base) | Extremely high – billions of active receivers worldwide. |
| Coexistence Tips | Protect adjacent passive Radio Astronomy below 1668.4–1668.7 MHz (RAS). Control adjacent-band emissions and out-of-band spurious. Coordinate satellite downlinks and ground reception sites; avoid high-power terrestrial emissions. |
| Latency Class | N/A (Satellite downlink / agency reception) |
| Device Hotspots (Scoped && Tagged) | Fixed meteorological satellite ground stations, national weather agency facilities, radiosonde launch sites, and research institutions. No consumer, mobile, or mass‑market device hotspots. |
