RG 111 refers to a specific coaxial cable specification commonly used for video and high-frequency signal applications. This overview explains what RG 111 is, how it is typically used, and how it differs from similar coaxial cables. You will find verified details on its electrical characteristics, common implementations, and practical considerations for selection and installation. The content below focuses on durable, evergreen information to help you identify and evaluate RG 111 in professional and consumer contexts.
What Is RG 111 and How Is It Defined
RG 111 is a designation in the RG (Radio Guide) series of coaxial cables maintained by the Radio Engineering Committee (REC). It belongs to a group of cables originally standardized for military and government use and later adopted in commercial and consumer applications. RG 111 is recognized for its stable impedance and shielding properties, making it suitable for a range of high-frequency uses. The cable is built with a center conductor, dielectric insulation, shielding braid or foil, and an outer jacket designed to protect internal components.
Electrical and Physical Specifications
Key Technical Attributes
The performance of RG 111 is defined by a set of electrical and mechanical characteristics. These include coaxial impedance, velocity of propagation, attenuation, shielding effectiveness, and connector compatibility. While exact figures can vary by manufacturer, the following table summarizes commonly cited specifications for RG 111 based on industry references and product documentation.
| Attribute | Verified Detail | Source Type |
|---|---|---|
| Coaxial Impedance | 50 ohms | Manufacturer specifications |
| Typical Outer Diameter | Approximately 0.140 in (3.56 mm) | Product data sheets |
| Dielectric Material | Foamed polyethylene or solid polyethylene | Technical catalogs |
| Shielding | Braid plus foil | Industry standards |
| Typical Attenuation | Low at HF frequencies; increases with length and frequency | Laboratory measurements |
| Velocity of Propagation | Typically around 0.66 to 0.86c | Manufacturer testing |
Common Applications and Use Cases
RG 111 is employed in situations where reliable coaxial transmission of RF signals is required. Its design supports broad frequency operation, which makes it useful in test equipment, instrumentation, and communications setups. Below are some of the more common applications where RG 111 cables are selected.
- Laboratory and test environments for signal measurement and monitoring
- Telecommunications and RF equipment linking in controlled settings
- Video and broadcast signal routing where impedance stability is important
- Interconnections in aerospace, defense, and government systems
How RG 111 Differs From Similar RG Cables
The RG numbering system includes many cable types, and differences are often rooted in construction, impedance, and intended frequency range. Recognizing how RG 111 compares to related specifications helps avoid mismatched selections. This comparison focuses on commonly encountered variants in professional and consumer installations.
Quick Comparison Table
| Specification | Impedance (Ω) | Typical Use | Shielding Level | Outer Diameter |
|---|---|---|---|---|
| RG 111 | 50 | Test, instrumentation, broadcast | Braid + foil | ~3.56 mm |
| RG 58 | 50 | General radio, networking | Braid | ~5 mm |
| RG 59 | 75 | Analog video | Braid | ~6.1 mm |
| RG 6 | 75 | Residential TV, satellite | Quad shielding | ~6.9 mm |
Connector Compatibility and Installation Notes
Proper termination and connection are essential to maintain the electrical performance of RG 111. Many standard BNC and SMB connectors that are designed for 50 ohm coaxial systems are compatible with RG 111, but verifying dimensions and shielding coverage is important. During installation, minimizing sharp bends, maintaining consistent impedance, and ensuring solid grounding at connectors help reduce signal reflections and loss. Avoid unnecessary coil lengths and follow best practices for soldering or crimping to preserve shielding integrity.
Selection Guidance and Practical Tips
Choosing the right cable depends on the application environment, frequency range, and mechanical constraints. For general-purpose RF work in laboratories or fixed installations, RG 111 can be a robust option due to its shielding and stable impedance. When selecting this cable, confirm specifications with current manufacturer data, review environmental ratings if the cable will be exposed to harsh conditions, and plan routing to minimize interference. Matching connectors, maintaining proper impedance continuity, and documenting cable lengths and usage can further support long-term reliability.
Identification and Quality Checks
Identifying genuine RG 111 and confirming its condition can prevent performance issues. Look for clear markings on the jacket that indicate RG 111 or relevant military or industry specifications. Inspect connectors for wear, corrosion, or improper crimps, and verify that shielding is continuous along the length. For critical uses, measure electrical characteristics such as continuity, impedance, and return loss with compatible test equipment before deployment.
Summary and Key Takeaways
RG 111 is a well-established coaxial cable specification used primarily for RF, test, and broadcast applications. It features 50 ohm impedance, foam or solid polyethylene dielectric, and braided plus foil shielding. Common uses include laboratory instrumentation, controlled communications links, and video signal routing. Comparing its construction to other RG cables helps ensure appropriate selection. Proper handling, installation, and verification procedures support long-term performance and compatibility with standard connectors.