🌐 Summary
42 MHz (range 42–43 MHz) is part of Public Safety / Business VHF within the VHF Low spectrum.
Quick summary: Operating at 42 MHz in the lower VHF spectrum, this frequency supports public safety, business radio. Services in this band utilize VHF propagation characteristics for reliable regional communications.
Primary use: Public safety, business radio
Common applications: Police, fire, forestry, utilities
Technology: FM narrowband
Quick Facts Public safety and business communications in the low VHF band. Police, fire, and emergency services in some jurisdictions still use these frequencies. Good building penetration compared to UHF.
Source: 47 CFR Part 90
📶 Band & Identity
| Field | Value |
|---|---|
| Frequency (MHz) | 42 |
| Lower Band Edge (MHz) | 42 |
| Upper Band Edge (MHz) | 43 |
| Band Name | Public Safety / Business VHF |
| Spectrum Block | VHF Low |
| Popular Name | VHF Low Band (Public Safety) |
| Allocation Status | Active |
| Exclusive / Shared | No (shared allocation) |
| Protected Services | |
| Related Frequencies | 37-47 MHz band |
📜 FCC Rules & Licensing
| Field | Value |
|---|---|
| FCC Service Type | PUBLIC SAFETY / INDUSTRIAL/BUSINESS |
| FCC Secondary Services | See primary allocation |
| FCC Part Number | Part 90 |
| FCC Rule Section | 47 CFR Part 2 (Frequency Allocations) |
| License Required | Yes |
| 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 | FM narrowband |
| Modulation | FM / C4FM (P25) |
| Typical Bandwidth | 12.5 kHz / 25 kHz |
| Transmitter Type | P25 radio transmitter |
| Receiver Type | P25/APCO radio receiver |
| Typical Power (W) | 1-50 |
| Maximum Power Limit | Varies by service type |
| ERP Limit | Varies |
| Antenna Height Limits | Varies |
| Antenna (Quarter-Wave) | 5.57 ft (169.8 cm) |
| Duplex Mode | Varies |
| Paired Frequency | Varies by application |
| Channelization | 12.5, 25 kHz |
| 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 | Public safety, business radio |
| Common Applications | Police, fire, forestry, utilities |
| Can You Listen? | Yes – but often encrypted in major cities (varies by location) |
| Encryption Status | Mixed – VHF/UHF analog often not encrypted, digital varies |
| Popular Radio Models | SDR receivers (RTL-SDR Blog V3, Airspy HF+, SDRplay RSPdx), VHF receivers, scanner receivers |
| License Holders | Various (government, commercial) |
| Major Operators | Police, fire departments, utilities |
| Government Use | No |
| Military Use | No |
| Public Safety | Yes |
| Critical Infrastructure | No |
| Amateur Radio | No |
| ISM Band | No |
| Unlicensed Operation | No |
| Consumer Equipment | No |
| Common Devices | Police radios, fire radios, EMS equipment, P25 radios |
| Receive Only | No |
| Radio Astronomy | No |
| Satellite Downlink | No |
| Passive Service | No |
| Spectrum Occupancy (Estimated) | Moderate (30-50%) |
| Urban vs Rural | Primarily urban/suburban |
| Deployment Density | Moderate |
🌎 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 |