🌐 Summary
43 MHz (range 43–44 MHz) is part of Radio Astronomy within the VHF Low spectrum.
Quick summary: The 43 MHz frequency falls within lower VHF allocations designated for radio astronomy observations. Users benefit from VHF’s superior ground-wave propagation and obstacle penetration at these wavelengths.
Primary use: Radio astronomy observations
Common applications: Radio telescope observations, cosmic signal detection, astronomical research, space phenomena study
Technology:
Quick Facts Low VHF communications band. Used for various land mobile services including business radio, industrial operations, and some government services.
Source: 47 CFR Part 2
📶 Band & Identity
| Field | Value |
|---|---|
| Frequency (MHz) | 43 |
| Lower Band Edge (MHz) | 43 |
| Upper Band Edge (MHz) | 44 |
| Band Name | Radio Astronomy |
| Spectrum Block | VHF Low |
| Popular Name | VHF Low Band |
| Allocation Status | Active |
| Exclusive / Shared | No (shared allocation) |
| Protected Services | Radio astronomy (protected internationally) |
| Related Frequencies | 38-48 MHz band |
📜 FCC Rules & Licensing
| Field | Value |
|---|---|
| FCC Service Type | RADIO ASTRONOMY |
| FCC Secondary Services | See primary allocation |
| FCC Part Number | Part 2 |
| FCC Rule Section | 47 CFR Part 2 (Frequency Allocations) |
| License Required | No |
| License Type | Varies by service |
| License Fee Type | Application fee |
| Annual Regulatory Fee | Varies |
| License Term (Years) | 10 |
| Renewal Expectancy | High |
| Auction History | Not auctioned (comparative licensing) |
| Refarming Status | Stable |
| Geographic Restrictions | Border coordination may apply near Canada/Mexico |
| Quiet Zones | Radio astronomy protection zones |
| Coordination Required | Frequency coordination required |
| Warnings / Notices | Unauthorized transmission is illegal and subject to FCC enforcement |
⚙️ RF & Technical
| Field | Value |
|---|---|
| Technology | |
| Modulation | |
| Typical Bandwidth | Varies (passive observation) |
| Transmitter Type | |
| Receiver Type | Radio telescope receiver |
| Typical Power (W) | |
| Maximum Power Limit | Varies by service type |
| ERP Limit | Varies |
| Antenna Height Limits | Varies |
| Antenna (Quarter-Wave) | 5.44 ft (165.9 cm) |
| Duplex Mode | Varies |
| Paired Frequency | Varies by application |
| Channelization | Varies by service |
| Guard Bands (kHz) | Varies |
| Emission Designator | Varies |
| Emission Mask | FCC standards |
| Part 15 Device Limits | Not applicable (licensed spectrum) |
| Spread Spectrum Allowed | No |
| Frequency Hopping Allowed | No |
| Power Control Required | No |
🌤️ Propagation
| Field | Value |
|---|---|
| Propagation Mode | Line of sight, some diffraction |
| Typical Range (Miles) | 10-50 |
| Day vs Night Differences | Minimal |
| Atmospheric Effects | Minimal |
| Interference Concerns | Standard adjacent channel and co-channel interference |
🛡️ Ecosystem
| Field | Value |
|---|---|
| Primary Use | Radio astronomy observations |
| Common Applications | Radio telescope observations, cosmic signal detection, astronomical research, space phenomena study |
| Can You Listen? | Receive only – passive observation (no transmissions) |
| Encryption Status | Varies by user and system type |
| Popular Radio Models | SDR receivers (RTL-SDR Blog V3, Airspy HF+, SDRplay RSPdx), VHF receivers, scanner receivers |
| License Holders | Various (government, commercial) |
| Major Operators | Government agencies, commercial operators |
| Government Use | No |
| Military Use | No |
| Public Safety | No |
| Critical Infrastructure | No |
| Amateur Radio | No |
| ISM Band | No |
| Unlicensed Operation | No |
| Consumer Equipment | No |
| Common Devices | VHF scanner receivers, SDR receivers (RTL-SDR, Airspy), wideband communications receivers |
| Receive Only | Yes |
| Radio Astronomy | Yes |
| Satellite Downlink | No |
| Passive Service | No |
| Spectrum Occupancy (Estimated) | Varies |
| Urban vs Rural | Varies by location |
| Deployment Density | Low-Medium |
🌎 International
| Field | Value |
|---|---|
| ITU Region 2 Allocation | Fixed / Mobile |
| International Harmonization | ITU Region 2 allocation |
| Cross-Border Coordination | No |
| Year Allocated | Various |
| Legacy Uses | Historical allocations stable |
| Future Plans | Stable |
🧾 Compliance
| Field | Value |
|---|---|
| FCC Certification Required | No |
| Equipment Authorization Type | Certification required |
| FCC ID Required | No |
| Compliance Testing | FCC equipment authorization required |