RG-59: The Essential Guide to Coaxial Cable Technology for Video, RF and CCTV

RG-59 is one of the most enduring coaxial cables used in video and RF applications. Its 75-ohm impedance and sturdy construction have made it a staple for decades, from classic CCTV installations to modern CCTV, amateur radio, and broadcast systems. This comprehensive guide unpacks what RG-59 is, how it works, where it shines, and how to choose, install and test it for reliable performance. Whether you are refurbishing an old system or designing a new one, understanding RG-59 will help you make informed decisions and achieve higher signal integrity with practical, real‑world advice.

What is RG-59? A clear overview of the 75-ohm coaxial standard

RG-59 is a type of coaxial cable defined by its construction and its characteristic impedance. The “RG” prefix originates from a U.S. military designation, and in common parlance RG-59 refers to a 75-ohm coaxial cable widely used for analogue video, CCTV, and general-purpose RF distribution. Its core features include a centre conductor, an insulating dielectric, a conductive shielding layer, and an outer jacket. The typical arrangement allows for shielding against external interference and a predictable impedance that is well-suited to video bandwidths and short‑ to medium‑distance runs.

Key construction elements of RG-59

• Centre conductor: The copper or copper-clad steel core provides the signal path.
• Dielectric: An insulating layer around the conductor maintains a stable impedance and supports capacitance control.
• Shielding: A combination of foil and braided shielding minimizes electromagnetic interference and crosstalk.
• Jacket: An outer sheath protects the internal layers from moisture, abrasion and environmental exposure.

In practice, RG-59 offers a good balance between flexibility, signal integrity, and cost. Its 75-ohm impedance makes it particularly compatible with analogue video and many consumer-grade RF devices. For high‑frequency, long‑distance, or ultra‑low‑loss needs, other coax types such as RG-6 or specialised low‑loss cables may be preferred, but RG-59 remains a reliable choice for many standard installations.

History and standards behind RG-59

The RG family of cables has a storied history tied to military and broadcast use. RG-59 is among the most widely referenced versions, especially in the UK and Europe for video and CCTV. Understanding its history helps explain why it is still seen in modern systems, even as new materials and designs have emerged.

Origin of the RG nomenclature

The RG in RG-59 stands for “radio guide,” a designation historically applied to coaxial cables used for radio and television distribution. Over the years, many RG cables have been repurposed for civilian applications, and RG-59 has maintained a reputation for practicality and availability. The term has become ubiquitous in the trade, and technicians often refer to “RG-59” as shorthand for 75-ohm video-quality coax.

Standard families and compatibility

RG-59 is frequently listed as RG-59/U or similar designations, indicating a specific family variant with 75-ohm impedance. Within the same family, there can be minor variations in jacket material, shielding configuration, and pliability. When selecting RG-59, it’s important to check the jacket rating (indoor vs outdoor, UV resistance, fire rating in certain jurisdictions) and the shielding arrangement to match the installation environment and regulatory requirements.

When to choose RG-59: Applications and limitations

RG-59 excels in particular niches where its combination of impedance, capacitance and flexibility suits short- to medium‑distance video and RF distribution. It is a common choice for CCTV installations, home theatre setups, and certain audio/video signal paths. However, for long runs or high‑bandwidth digital video, other cables may provide better performance with reduced attenuation.

Video and CCTV applications

Analogue CCTV and early digital video systems often relied on RG-59 due to its 75-ohm impedance, compatibility with BNC connectors, and availability. In modern settings, RG-59 can still be a viable option for short runs between a camera and a recorder, or for test setups in studios and classrooms. Its flexibility helps with installations in tight spaces, around corners and behind furniture where bulkier cables would be impractical.

Signal loss and distance considerations

Like all coaxial cables, RG-59 experiences attenuation that increases with frequency and distance. Over short channels, the loss is typically manageable; as runs extend beyond several tens of metres, signal strength can decline, affecting image quality or RF performance. When planning a system, calculate the expected loss at the operating frequency and compare it with the required signal margin to determine whether RG-59 is suitable for the intended distance.

Comparison with RG-6 and RG-58

RG-58 is another 50-ohm coax used for different RF applications, while RG-6 offers lower loss per metre and is widely used for satellite, cable television and high‑definition video runs. Compared with RG-6, RG-59 has higher capacitance and greater attenuation at higher frequencies, but for short runs and 75-ohm video networks, RG-59 remains a practical and cost‑effective choice. Choosing between RG-59 and RG-6 or RG-58 hinges on impedance compatibility, the distance of transmission, frequency range, and environmental conditions.

Electrical and mechanical characteristics of RG-59

Understanding the electrical and mechanical traits of RG-59 helps in predicting performance and determining suitability for a given installation.

Impedance, bandwidth and attenuation

RG-59 is designed around a 75-ohm impedance, which aligns with most analogue video and broadcast standards. The usable bandwidth typically extends from DC up into several hundred megahertz, depending on construction and shielding. Attenuation increases with frequency and length; in practical terms, a few tens of metres of RG-59 in an analogue video chain will usually offer acceptable signal strength, whereas longer runs or higher frequencies may require amplification, buffering, or alternative cabling.

Dielectric and shielding performance

The dielectric material in RG-59 provides consistent impedance across temperature variations, while the shielding (often a combination of foil and braid) guards against interference and external noise. The quality of shielding directly influences the cable’s ability to resist cross‑talk and electromagnetic interference, which is crucial in busy environments such as studios, control rooms, and near power lines or other RF sources.

Jacket materials and environmental resilience

Jacket materials vary by product line. Some RG-59 cables feature PVC jackets suitable for indoor use, while others have UV‑resistant or moisture‑proof jackets for outdoor or underground installations. In an industrial or outdoor context, selecting a jacket rated for moisture, heat or chlorine exposure may be essential to preserve lifespan and signal integrity.

Connectorisation and installation tips for RG-59

Connector choice and proper termination are critical for preserving signal quality in RG-59 installations. BNC connectors are ubiquitous for 75-ohm coax, though RCA connectors may be found in consumer setups. Correct stripping, crimping or soldering, and ensuring a solid, air‑free contact are essential steps.

Common connectors: BNC, RCA and other variants

BNC connectors are widely used with RG-59 due to their secure snap‑fit and reliable 75-ohm performance. RCA connectors are common in consumer AV gear and can be used with short RG-59 runs, but engineers prefer BNC for professional contexts where ruggedness and repeatable impedance are valuable. In some installations, F connectors or other variants may appear, but ensure the connector’s impedance matches the cable and the system requirements to avoid reflections.

Best practices for trimming, terminating and routing

• Use proper stripping tools to expose only the intended conductor length and avoid nicking the shielding.
• Maintain consistent impedance through the termination; use proper crimp or solder techniques as recommended by the connector manufacturer.
• Avoid sharp bends and kinks; use gentle curves to prevent micro‑cracks in the shield and dielectric, which can degrade performance.
• Secure runs to minimise movement and wear, protecting against environmental damage in dusty or humid locations.

Testing and troubleshooting RG-59 installations

Reliable RG-59 performance hinges on thorough testing during and after installation. A combination of simple and advanced tests can identify issues early and save time in the long run.

Continuity and shorts testing

Begin with a basic continuity test to confirm the inner conductor is continuous along the cable length and that there are no shorts to the shield. A basic multimeter with the resistance setting can detect gross faults; advanced cable testers provide more precise confirmations and can map the entire length for inconsistencies.

Signal quality tests and measuring loss

For video‑specific installations, testing for signal loss is common. Using a waveform monitor, oscilloscope, or dedicated coaxial test equipment can help verify that the RG-59 line delivers acceptable levels of amplitude and stability. Match the expected attenuation to the system’s tolerance and the equipment’s input sensitivity to judge whether RG-59 is performing satisfactorily over the chosen distance.

Variants and terminology: RG-59 vs RG-59/U and related nomenclature

In practice, you may encounter several labels for the same general cable family. RG-59/U is a frequently seen designation, indicating a particular version of RG-59 used in civilian markets. The “/U” suffix helps distinguish it from other variations and ensures compatibility with standard 75-ohm interfaces. Always verify impedance, shielding and jacket features on datasheets rather than relying solely on the label, as product lines can differ in construction.

What does RG-59/U denote?

The suffix “/U” denotes a general utility grade version of RG-59. It is intended for a broad range of use cases and tends to offer a good compromise between flexibility, durability and cost. In professional projects, confirm the exact construction details with the supplier to ensure it meets the system’s requirements.

Other alternatives and regional naming

Regional naming conventions may vary, but the essential electrical characteristics remain the same: RG-59 typically refers to a 75-ohm coax designed for video and short RF links. For international projects, you may encounter similar cables with different colour codes, jacket materials, or standard references. Always align the product with the engineering specs rather than the marketing name.

Buying guide: How to select RG-59 for your project

Choosing RG-59 involves balancing impedance consistency, attenuation, mechanical durability and cost. Here are practical steps to help you decide.

Indoor vs outdoor use

For indoor CCTV or studio setups, RG-59 with a standard PVC jacket may suffice. For outdoor installations or environments with potential moisture exposure, select a jacket with UV resistance or moisture barriers. If the system must operate in harsh climates, consider upgrades to jackets with enhanced weatherproofing or shield‑integrity features.

Climate resistance and fire ratings

In certain jurisdictions, fire safety standards and cable ratings are required for building installations. Check for compliance with local codes and select RG-59 products that carry appropriate fire-retardant ratings or certification marks. This ensures safety and reduces the risk of compliant issues during inspections.

Future prospects for RG-59 in a streaming and CCTV world

While digital, wireless and fibre‑based solutions continue to expand, RG-59 remains relevant for many existing networks and specific niches. In retrofit projects, legacy CCTV systems and certain RF applications still rely on 75-ohm coax. In new builds, the choice often depends on a balance of cost, speed, distance and compatibility with existing equipment.

Are coax still relevant?

Coaxial cabling, including RG-59, continues to be relevant for controlled, shielded signal paths, reliable connectors, and straightforward installation. In environments where wireless or fibre are impractical, or where a finite budget dictates the use of established hardware, RG-59 offers a dependable option with predictable performance and broad supplier support.

Integrated and hybrid cabling options

Modern installations may combine RG-59 with fibre media converters, RF distribution amplifiers, or hybrid cables that integrate multiple signal paths in a single run. When adopting such approaches, ensure the RG-59 segment remains within the cable’s optimal distance and frequency range and that transitions between media preserve impedance matching and grounding practices.

Common misconceptions around RG-59

Several myths persist about RG-59. For example, some assume it is unsuitable for any modern video system or that all 75-ohm coax behaves identically. In reality, the key is to assess the frequency content, length, environment and connector quality. High‑quality RG-59 with proper terminations and shielding can deliver reliable results in many scenarios, while inferior products or poor installations will underperform regardless of the cable type.

Practical tips for maintenance and longevity

To maximise the lifespan and performance of RG-59 installations, follow these simple guidelines:

• Label and document runs to simplify future maintenance or upgrades.
• Inspect connectors for corrosion, loose fittings or signs of wear during regular checks.
• Avoid physical damage from compression, pinching or excessive bending radii.
• Store spare RG-59 cables in anticipation of future upgrades or repairs, with proper reels or spools to prevent kinking.

Conclusion: Practical guidance for working with RG-59

RG-59 remains a versatile and practical choice for a wide range of video and RF applications. Its 75-ohm impedance, ease of handling and widespread availability make it a logical option for both retrofits and new installations where short‑to‑medium distance transmission is common. By understanding the construction, connectors, environmental considerations and testing methods, you can design reliable systems that deliver solid performance without overpaying for unnecessary complexity. Remember to match the cable to the application, select appropriate jacket materials and connectors, and verify installation integrity through careful testing. With the right approach, RG-59 can be a dependable backbone for high‑quality video and RF signal paths for years to come.