Quick Answer / Summary: An RG59 cable (Radio Guide 59) is a flexible 75-ohm coaxial cable featuring a 20 AWG (0.81mm) center conductor and an outer diameter of approximately 6.15mm (0.242 inches). Designed for low-frequency baseband video (under 50 MHz), it is the global standard for analog CCTV surveillance cameras, composite video, and studio video patch cords.
In analog video surveillance installations, professional video production patchbays, and retro CRT gaming setups, high-flexibility 75-ohm coaxial lines are essential for routing video signals without stiff cable spring-back. Specifying precision rg59 cable—engineered with a 20 AWG copper center conductor, solid polyethylene dielectric, and a heavy 95% bare copper braided shield—delivers pristine baseband video transmission and superior low-frequency ground hum rejection.
Physical Architecture: 20 AWG Conductor and 95% Bare Copper Braid
Why RG59 is uniquely engineered for baseband video: 1. 20 AWG Solid or Stranded Bare Copper Conductor: Smaller than RG6, providing lower physical mass and smaller bend radiuses (approx. 1 inch), allowing cables to coil smoothly inside tight camera junction boxes and equipment racks; 2. 95% Bare Copper Braid Shielding (Why Foil Fails at Baseband): Aluminum foil shields used in RG6 are effective against high-frequency RF (megahertz/gigahertz), but have high electrical resistance that performs poorly against 60 Hz electrical hum induced by building AC power lines. RG59 incorporates a heavy, tightly woven 95% bare copper braid that provides an ultra-low DC resistance ground path, draining ground hum currents and completely eliminating video hum bars (rolling horizontal dark bars across monitor screens); 3. Solid Polyethylene Dielectric: Provides high crush resistance and ensures that mechanical pinching does not alter characteristic impedance (75 ohms $\pm 3 \ \Omega$) in mobile broadcast applications.
Siamese RG59 Cable (Coax + 18/2 Power Pair)
In security camera installations, ‘Siamese’ RG59 features the coaxial video cable bonded side-by-side with an 18 AWG 2-conductor (Red/Black) power wire in a figure-8 jacket, enabling one-pull installation for video and 12V DC / 24V AC camera power.
Distance Limitations for Analog and HD-CCTV
For standard analog CVBS video, RG59 transmits cleanly up to 250 meters (800 feet); for high-definition analog formats (HD-TVI, CVI, AHD 1080p to 4K), transmission distance is limited to 150-200 meters before high-frequency roll-off degrades color resolution.
BNC Compression and Twist-On Termination
RG59 cables terminate universally with 75-ohm male BNC connectors; while twist-on connectors exist for quick repairs, commercial installations require 360-degree radial BNC compression connectors to prevent moisture and pull-out.
RG59 Coaxial Cable Specifications and Baseband Performance
| Specification Parameter | Standard RG59 Coaxial Cable | RG59 Siamese (Coax + Power) | CCTV Installation Impact |
|---|---|---|---|
| Center Conductor Gauge | 20 AWG Solid Bare Copper | 20 AWG Solid BC + 18/2 Power | Transmits low-resistance video and camera power |
| Shielding Construction | 95% Tightly Woven Bare Copper Braid | 95% Bare Copper Braid | Completely eliminates 60Hz AC power hum bars |
| Cable Outer Diameter | 6.15 mm (0.242 inches) | 6.15mm + 4.5mm (Figure-8) | Flexible, easy to pull through tight 1/2″ conduit |
| Loss @ 50 MHz (Video) | ~ 1.8 dB / 100 ft (Low-Loss) | ~ 1.8 dB / 100 ft | Transparent passband for composite & HD-TVI video |
| Primary Intended Role | Analog video monitors, BNC patch | Security cameras, CCTV DVRs | Single-pull wiring simplifies security camera installs |
Real-World Application Scenarios
Commercial CCTV analog and HD-TVI/CVI camera wiring, professional broadcast studio patchbays, connecting classic video game consoles to Sony PVM/BVM monitors, and composite video distribution.
Recommended Internal Resources
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Frequently Asked Questions (FAQ)
Q: Can I use an RG59 cable for satellite TV or cable internet?
A: No; RG59 has excessive attenuation at frequencies above 1 GHz (losing nearly double the signal of RG6), which will cause severe pixelation or total signal loss on satellite and cable modem lines; use RG6 instead.
Q: What causes horizontal rolling lines (hum bars) on an analog CCTV camera?
A: Hum bars are caused by a ground loop: a voltage difference between the camera ground and the DVR ground causes 60 Hz AC current to flow along the cable shield; using RG59 with a 95% pure copper braid (or adding an inline ground loop isolator) eliminates this hum.