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RF & Coax
Coaxial cable types, loss per 100ft, RF connector types, VSWR to return loss conversion, and free space path loss reference.
Coaxial Cable Types
| Type | Impedance | Vel. Factor | Max Freq | Common Use |
|---|---|---|---|---|
| RG-58 | 50 Ω | 0.66 | 1 GHz | Short runs, test leads, mobile HF |
| RG-8X | 50 Ω | 0.78 | 1 GHz | HF and VHF mobile, flexible |
| RG-213 | 50 Ω | 0.66 | 1 GHz | HF base stations, low loss |
| LMR-400 | 50 Ω | 0.85 | 2.5 GHz | VHF/UHF base, very low loss |
| LMR-600 | 50 Ω | 0.87 | 2.5 GHz | High power, long runs |
| RG-174 | 50 Ω | 0.66 | 1 GHz | Pigtails, GPS, tight spaces |
| RG-59 | 75 Ω | 0.66 | 1 GHz | Video, CCTV, CATV |
| RG-6 | 75 Ω | 0.82 | 3 GHz | Satellite, digital CATV |
| RG-11 | 75 Ω | 0.84 | 1 GHz | CATV trunk, long runs |
Coaxial Cable Loss Reference
Approximate attenuation in dB per 100 feet at common frequencies. Actual loss varies by manufacturer and temperature.
| Cable | 30 MHz | 150 MHz | 450 MHz | 1 GHz |
|---|---|---|---|---|
| RG-58 | 2.5 dB | 6.1 dB | 11.8 dB | 20.0 dB |
| RG-8X | 2.0 dB | 4.5 dB | 8.5 dB | 13.5 dB |
| RG-213 | 1.2 dB | 2.7 dB | 5.0 dB | 8.0 dB |
| LMR-400 | 0.7 dB | 1.5 dB | 2.7 dB | 4.1 dB |
| LMR-600 | 0.4 dB | 1.0 dB | 1.7 dB | 2.7 dB |
| RG-174 | 5.0 dB | 11.6 dB | 20.5 dB | 31.0 dB |
| RG-59 | 1.9 dB | 4.2 dB | 7.5 dB | 12.0 dB |
| RG-6 | 1.1 dB | 2.7 dB | 4.7 dB | 7.2 dB |
RF Connector Types
| Connector | Impedance | Frequency Range | Common Use |
|---|---|---|---|
| PL-259 (UHF) | Unspecified | DC – 300 MHz | HF/VHF amateur and marine radio |
| BNC | 50 or 75 Ω | DC – 4 GHz | Test equipment, aviation electronics |
| TNC | 50 or 75 Ω | DC – 11 GHz | Mobile radios, vibration-prone environments |
| N-Type | 50 or 75 Ω | DC – 11 GHz | VHF/UHF base antennas, high power |
| SMA | 50 Ω | DC – 18 GHz | Portable radios, GPS, WiFi modules |
| SMB | 50 or 75 Ω | DC – 4 GHz | Automotive, broadcast equipment |
| F-Type | 75 Ω | DC – 3 GHz | Cable TV, satellite, DOCSIS modems |
| MCX | 50 or 75 Ω | DC – 6 GHz | GPS, compact electronics |
| SC (fiber) | N/A | Optical | Fiber optic — push-pull, data networks |
| LC (fiber) | N/A | Optical | Fiber optic — small form factor, SFP |
| ST (fiber) | N/A | Optical | Fiber optic — bayonet, multimode |
VSWR to Return Loss Conversion
SWR below 1.5:1 is acceptable for most installations. Above 2:1 indicates a significant mismatch requiring investigation.
| VSWR | Return Loss | Reflected Power | Efficiency | Rating |
|---|---|---|---|---|
| 1.0:1 | ∞ dB | 0% | 100% | Perfect |
| 1.1:1 | 26.4 dB | 0.2% | 99.8% | Excellent |
| 1.2:1 | 20.8 dB | 0.8% | 99.2% | Excellent |
| 1.5:1 | 14.0 dB | 4% | 96% | Good |
| 2.0:1 | 9.5 dB | 11% | 89% | Acceptable |
| 2.5:1 | 7.4 dB | 18% | 82% | Poor |
| 3.0:1 | 6.0 dB | 25% | 75% | Poor |
| 4.0:1 | 4.4 dB | 36% | 64% | Very Poor |
| 5.0:1 | 3.5 dB | 44% | 56% | Very Poor |
| 10.0:1 | 1.7 dB | 67% | 33% | Severe |
Free Space Path Loss Reference
Approximate free space path loss in dB at common frequencies and distances. Actual path loss varies with terrain, obstructions, and atmospheric conditions.
| Distance | 150 MHz (VHF) | 435 MHz (UHF) | 1575 MHz (GPS) | 2.4 GHz (WiFi) |
|---|---|---|---|---|
| 1 m | 16.0 dB | 25.2 dB | 36.4 dB | 40.1 dB |
| 10 m | 36.0 dB | 45.2 dB | 56.4 dB | 60.1 dB |
| 100 m | 56.0 dB | 65.2 dB | 76.4 dB | 80.1 dB |
| 1 km | 76.0 dB | 85.2 dB | 96.4 dB | 100.1 dB |
| 10 km | 96.0 dB | 105.2 dB | 116.4 dB | 120.1 dB |
| 100 km | 116.0 dB | 125.2 dB | 136.4 dB | 140.1 dB |