RG-59 Explained: The Classic Coaxial Cable That Keeps Video Sharp and Signals Strong
In the world of video transmission, the name RG-59 still rings a bell for engineers, technicians, hobbyists, and security installers across the United Kingdom and beyond. The RG-59 coaxial cable has earned a lasting reputation for reliability in analogue video, CCTV installations, and a wide range of signal distribution tasks. This article takes a thorough look at RG-59, exploring what it is, how it behaves, where it shines, and where modern alternatives may be a better fit. If you have ever wondered why RG-59 remains a staple or how to choose the right variant for a project, you’ll find clear guidance and practical tips here.
What is RG-59 and what does it do?
RG-59 is a type of coaxial cable designed to carry video and other high-frequency signals over relatively short to moderate distances. The term RG-59 is part of a historically assigned “RG” (radio guide) class, originating from military specifications but now widely used in civilian applications. The essential characteristics are a 75-ohm impedance, a central conductor surrounded by a dielectric, and an outer shield that protects the signal from external interference. In practice, RG-59 is commonly used for analogue video, CCTV feeds, and low‑to‑medium frequency video distribution tasks. For many installers, RG-59 is the classic choice when the goal is straightforward, dependable video transmission without high loss over modest lengths.
RG-59 vs RG-6: what makes them different?
One of the most frequent questions is how RG-59 compares with RG-6. Both cables share the same 75-ohm impedance and many construction principles, but there are key differences that affect performance and selection:
RG-59 typically uses a smaller conductor and a relatively thinner dielectric layer than RG-6. RG-6 often employs a thicker dielectric and a higher‑quality shielding arrangement, which helps reduce losses at higher frequencies. RG-6 generally exhibits lower signal loss per metre, especially at higher frequencies, which makes it more suitable for longer runs or digital HD video. RG-59 is still perfectly adequate for shorter runs or where cost and flexibility matter.
In short, while the two cables share a common goal—reliable video transmission—the choice between RG-59 and RG-6 hinges on distance, frequency content, and noise environment. For the term rg 59, many technicians will still reach for it when installing legacy CCTV or simple surveillance systems, where the practical performance is more than adequate.
The history and heritage of RG-59
Coaxial cables emerged in the mid-to-late 20th century as a practical solution for radio and video signals. The RG series, including RG-59, became a common shorthand for a range of flexible, affordable coax cables designed for domestic and professional use. The RG-59 family is often associated with 75-ohm systems used in video distribution and consumer electronics. Over time, alternative coax designs such as RG-6 and more modern, shielded variants offered improved performance, but RG-59 retained a niche due to its pliability, ease of termination, and cost-effectiveness. Today, many older installations still rely on RG-59 because the cable colour, diameter, and connector options align well with existing equipment and compatibility requirements.
Technical specifications you should know about RG-59
Understanding the core specifications will help you predict how RG-59 behaves in a given setup. Here are the most relevant figures and concepts:
Impedance and characteristic performance
RG-59 is designed to have a characteristic impedance of 75 ohms. This makes it well-suited to video signals, which also commonly use 75-ohm systems in broadcasting and CCTV. A mismatch anywhere along the chain can cause reflections, colour distortion, or loss of signal integrity. Keeping impedance consistent across the link is crucial for clean video.
Dielectric type and its impact
The dielectric material inside RG-59 typically consists of a polyethylene core or foam‑based dielectric, surrounding a copper conductor. The dielectric thickness and material influence the propagation speed of the signal (often expressed as a velocity factor) and the capacitance per metre. Thicker or higher‑quality dielectrics can help reduce capacitance per metre, which in turn affects signal loss and bandwidth.
Shielding and construction
RG-59 cables may feature a combination of metallic foil shielding plus braided copper or copper‑steel braiding. The shielding protects the inner conductor from electromagnetic interference (EMI) and radio frequency interference (RFI). The level of shielding directly impacts the cable’s performance in electrically noisy environments, such as near mains cables or devices with strong RF outputs. Note that some cheaper RG-59 variants may rely on single‑layer shielding, which is sufficient for modest installations but less robust against interference.
Loss characteristics and frequency response
Attenuation (signal loss) increases with frequency and length. For RG-59, typical losses are modest at standard video frequencies, but they accumulate with longer runs and higher bandwidth content. When planning a CCTV system, consider both the distance and the desired video resolution. The higher the resolution and the longer the run, the more you may benefit from a higher‑performing cable such as RG-6, or from using repeaters or active video distribution methods for longer paths.
Mechanical properties and flexibility
One of RG-59’s practical advantages is its flexibility. The smaller diameter makes it easier to route through walls, conduits, or tight spaces. This pliability is valuable in temporary setups, portable video work, or installations where route options are limited. However, this flexibility comes with a trade‑off: the cable can be more susceptible to physical damage if not carefully handled in harsh environments.
Common applications for RG-59
RG-59 serves a broad spectrum of uses beyond the classic CCTV. Here are some common applications where RG-59 remains relevant:
The most enduring application. RG-59 handles standard definition video feeds from cameras to recording equipment or monitors with dependable signal quality over reasonable distances. Short, straightforward runs of video content between equipment, especially where cost and ease of termination trump ultimate bandwidth. In some cases, RG-59 is used for low‑loss signal paths in consumer or hobbyist setups where the path length remains modest. For do‑it‑yourself enthusiasts building analogue video projects, RG-59 provides a forgiving, easy‑to‑work‑with option.
Choosing RG-59 for your project: practical guidance
Picking the right cable for the job is essential. If you have your eye on RG-59, use these practical considerations to guide your decision:
For short runs of analogue video, RG-59 is typically sufficient. If your path is longer or you plan to push high‑definition or digital signals, consider RG-6 or alternative distribution methods. RG-59 commonly terminates with BNC connectors for video. Ensure you choose the correct connector type and quality to maintain signal integrity. For some applications, push‑on or screw‑on connectors may be suitable, but BNC remains the standard for CCTV and professional video. If the installation involves long cable runs or substantial bending, select a construction with good flex characteristics and adequate shielding to resist wear and deformation over time. RG-59 is frequently more affordable than higher‑spec cables. If the budget is constrained and the performance requirements meet the job, RG-59 can be an economical solution.
Connectors and terminations: how RG-59 links up
Effective connections are critical to preserving signal quality. With RG-59, the most common mating devices are BNC connectors for video. Some installations also use F‑type connectors when RG-59 is adapted for radio frequency (RF) applications, though this is less typical for video. When terminating RG-59, ensure a clean, well‑crimped or well‑soldered connection, with adequate shielding continuity. A poor termination can introduce reflections, mismatch, and increased losses, undermining the advantages of even a well‑chosen cable.
BNC versus other connectors
BNC connectors are a standard choice for analogue video because they provide a solid, quick‑connect interface with reliable shielding. They are straightforward to install and are widely supported in CCTV equipment, video monitors, and older broadcast gear. If your system uses multiple brand devices, ensure you select compatible BNC variants (e.g., 50‑ohm BNCs for RF work vs 75‑ohm BNCs for video). For RG-59, 75-ohm BNC connectors are typical.
Proper installation safeguards include planning routes, maintaining conductor integrity, and minimising signal stress. Here are practical guidelines:
Keep bending radii gentle to prevent micro‑cracking of shielding or insulation. A common rule is to avoid radii smaller than ten times the cable diameter, though consult manufacturer guidance for exact values. Route cables away from sharp metal edges, hot surfaces, or moving components that could abrade the outer jacket over time. Keep RG-59 away from mains cables and other high‑voltage lines to minimise EMI pickup and cross‑talk. Secure the cable with appropriate fasteners that do not pinch or compress the sheath. Extreme temperatures can affect the dielectric and outer jacket. For outdoor or unheated spaces, select weather‑rated variants and protect with conduit where necessary.
Even with a well‑chosen cable, problems can arise. Here are typical symptoms and how to address them:
Check for loose connectors, damaged shielding, and corrosion on connectors. If the issue persists, test the run with a known good length of coax to determine whether the problem lies with the cable or the equipment. This can indicate impedance mismatch or poor shielding. Verify that all terminations use 75‑ohm components and that BNC connectors are properly seated. Inspect for physical damage along the run, kinks, or compression from fittings. Replace if any damage is detected. Route away from power lines and high‑EMI sources. Consider upgrading to better shielding or switching to RG‑6 for heavy interference environments.
The role of RG-59 has evolved as digital video and high‑resolution formats become dominant. For many low‑cost CCTV installations, retrofits, or educational projects involving analogue feeds, RG-59 remains a cost‑effective, straightforward solution. For professional installations with long cable runs, high‑definition video, or future‑proofing considerations, many engineers now lean toward RG‑6 or fibre‑optic solutions. The decision is often influenced by distance, required bandwidth, and environmental conditions rather than a single “best” cable. Nevertheless, RG-59’s flexibility and ease of handling mean it continues to see use in many settings, especially where legacy equipment or quick deployments are priorities.
When shopping for RG‑59, you may see several naming patterns. Some of the most common include:
- RG-59/U: The “/U” suffix indicates an ANSI designation for a universal version of the cable, commonly used in the United States but familiar to UK engineers as well.
- RG-59A, RG-59B: Variants with slight differences in shield construction or jacket material. The practical impact is usually related to shielding effectiveness and environmental resistance.
- RG‑59 coax with BNC connectors: A typical packaged option for video applications in CCTV and studio settings.
- RG-59 with weatherproof jackets: For outdoor or damp locations, variants with protective jackets offer better longevity and performance in adverse conditions.
Testing avoids surprises after the system is commissioned. Here are practical testing steps you can perform with readily available gear:
Use a multimeter to confirm the conductor continuity from end to end, ensuring there are no breaks in the copper core. A simple continuity test between the core and shield can reveal insulation faults. If the shield is shorted to the core, shielding integrity is compromised and the cable should be replaced. For professional results, use a time domain reflectometer (TDR) or a dedicated cable tester to verify the 75‑ohm characteristic and to locate any impedance discontinuities along the run. At a basic level, a signal generator and an observing device can help you estimate attenuation by comparing input and output levels across the intended frequency range.
Care and storage help maximise the life of your RG-59. Consider these best practices:
Prolonged UV exposure can degrade jackets and shielding. Use sealed containers or cabinets for long‑term storage. Moisture ingress can affect dielectric properties and shielding integrity. Store in a dry environment, and avoid exposing cables to damp conditions when not in use. For larger installations, label lengths and routes clearly. This helps maintenance staff scan routes quickly and reduces the risk of cutting or damage during later work.
As video technology evolves toward higher resolutions and new transmission standards, the practical relevance of RG-59 may shift. Digital video, IP-based surveillance, and the adoption of fibre optic links for long runs are driving changes. For short analogue links, educational demonstrations, or legacy installations, RG-59 remains a viable, cost‑effective option. In many projects, designers combine RG‑59 for legacy or local distribution with upgraded cables or active devices for longer, higher‑bandwidth legs of the system. When planning a mixed‑signal installation, treat RG‑59 as a reliable component in a broader toolkit rather than the sole solution for every scenario.
Is RG-59 suitable for high‑definition video?
RG-59 can carry higher‑definition signals only over short distances before attenuation becomes a concern. For modern HD or 4K video over longer runs, RG‑6 or fibre often provides better performance due to lower loss and higher shielding capabilities. If you only need standard definition or short‑range HD taps, RG-59 can still work effectively.
Can RG-59 be used outdoors?
Outdoor use is possible with weather‑rated jacket variants and appropriate protective measures, such as conduit and proper sealing at connectors. If the installation is subject to moisture, temperature fluctuations, or physical wear, select a version designed for outdoor use to preserve signal integrity.
What connectors are best for RG-59?
BNC connectors are the standard pairing for RG-59 in video applications. They provide reliable impedance matching and shielding continuity. When you see RG-59 described in product listings, it is often paired with BNC for CCTV or studio video work. Ensure connectors themselves are high quality and correctly tightened to avoid micro‑gaps that could degrade performance.
RG-59 remains a practical, time‑tested option for a broad spectrum of video transmission tasks. Its 75‑ohm impedance, flexible form, and ease of termination make it especially well suited to analogue CCTV setups, educational demonstrations, and hobbyist projects where cost and convenience are paramount. While the evolving landscape of digital video and long‑distance distribution might steer some planners toward RG‑6 or alternative technologies, RG-59 continues to serve as a reliable, well understood solution for many everyday applications. When you encounter the term rg 59 or RG-59, you are looking at a resilient piece of broadcasting heritage that can still deliver solid performance today, provided you match the right variant to the job, use proper connectors, and respect the practical limits of length and frequency.
With careful consideration of distance, environment, and connectivity, RG-59 can be a strong choice for achieving dependable video transmission. Whether you are refreshing an older CCTV installation or wiring up a compact classroom display, the practical wisdom behind RG-59 remains sound: choose the right cable, terminate it correctly, and ensure your system’s impedance is consistent from camera to monitor.