Quick answer: Exterior coax is a system, not a single part. The jacket has to survive UV and temperature swings, the cable needs a water block such as gel fill so moisture cannot travel along the braid, and the burial rating has to match the way the cable is installed. Most failures blamed on cable are really water at the connector, so a drip loop, a sealed boot and a sealed wall entry matter as much as the jacket compound.
Every outdoor coax failure follows the same script. The picture is fine for a season, then it degrades after rain, and someone replaces the splitter. By the time the cable is blamed, water has been sitting in the braid for months. Choosing the right jacket, water block and burial rating at purchase time is cheaper than diagnosing the same fault twice.
Jacket: UV, Temperature and Abrasion
Sunlight destroys an indoor PVC jacket within a few seasons. The plasticizer leaves, the surface chalks, then it cracks and lets water in. Exterior cable uses a black polyethylene jacket that resists UV, stays flexible in cold and does not go brittle in heat. Color matters far less than compound, so check the jacket material rather than the look of the spool.
Cold, heat and movement
Aerial and wall runs expand and contract with temperature. A jacket that stiffens below freezing will split at a bend or at a fastener. Leave a service loop and skip the tight cable ties, which pinch the dielectric and change impedance at that exact point.
Connector boots and drip loops
The connector is where water gets in. A rubber boot over the F connector, wrapped with self-amalgamating tape and finished with a drip loop below the entry, stops rain from running along the jacket into the fitting. Face the loop down and seal the wall penetration as well.
Water Ingress: Gel Fill and Burial Rating
Moisture travels through coax by wicking along the braid and by condensing inside a hollow dielectric. Gel fill blocks that path, and a flooded construction is the normal choice for anything outdoors, buried, or routed through a wet riser.
Flooded versus sealed designs
Flooded cable fills the spaces between braid and foil with a compound that stops water travel. Sealed designs use a different barrier and are quicker to terminate. Both beat an indoor jumper outdoors, where one pinhole in the jacket is enough to start corrosion in the braid.
What burial actually requires
Direct burial needs a jacket rated for it, protection from stones and tools, and a depth that matches local code. In conduit the conduit protects the cable, yet water still collects inside the pipe, so gel fill and a sealed connector remain necessary. Never assume conduit means dry.
Loss, Moisture and the Comparison Table
RG6 attenuation runs roughly 6 dB per 30 m at 1 GHz, and that figure is measured on dry cable. Water in the braid raises loss and shifts impedance, so a path that tested clean in spring can fail in the rainy season.
| Feature | Indoor jumper | Exterior grade | Why it matters |
|---|
| Jacket | PVC | UV stable polyethylene | PVC cracks in sunlight |
| Water block | None | Gel fill | Stops moisture along the braid |
| Burial | Not rated | Rated for direct burial | Handles moisture and crush load |
| Attenuation at 1 GHz | About 6 dB per 30 m | About 6 dB per 30 m | Loss follows the RG6 design |
When a customer reports a signal that fades after rain, the cable is usually the last thing to replace and the connector is the first thing to open. Measure loss at the far end, then inspect the fitting before anyone orders a new spool.
Practical scenarios
- House drop: the run from pole or pedestal to the wall needs a UV jacket, a drip loop and a grounded entry, not an indoor jumper pushed through the siding.
- Direct burial: a garden run to a shed should use flooded cable rated for burial, laid in sand or conduit with the connector kept above grade.
- Marine and dock: salt spray attacks braid and fittings, so tinned construction and sealed connectors matter more than the attenuation figure on the datasheet.
- Camera pole: a short exterior drop to an analog camera benefits from a service loop and a boot, because the connector sits in the weather rather than the cable.
FAQ
Can I use indoor coax outside?
Only as a temporary fix. An indoor PVC jacket breaks down under UV, and the cable has no water block, so moisture reaches the braid within a season or two.
Does exterior coax need a ground block?
Where the cable enters a building it should pass through a properly bonded ground block, following local code and the service provider practice for that area.
Does gel fill change signal loss?
Not in any meaningful way while the cable is dry. The benefit is keeping it dry, since water is what raises loss and shifts impedance over time.
Next step
Before you order, compare jacket and shield construction in our RG6 engineering guide, then read the sealing steps in the outdoor and marine install notes. The coax connector types overview shows which fitting suits each jacket and cable diameter.
