Published on 10/13/2026
A stockroom finds a spool of RG58 from 2009. The jacket is stiff and chalky, and a purchasing manager asks whether it is still good. A second engineer has an RG316 jumper from the same year that looks new. Both are coax, and they age very differently.
Short answer: coax cable does degrade, but the rate depends on the jacket and dielectric. PTFE and FEP cables like RG316 can sit for decades. PVC jacket cables like RG58 and RG174 can harden, crack or lose plasticizer in 10 to 20 years, faster in sun or heat. Most failures are caused by moisture, UV and flexing, not by the signal.
This guide covers what ages, how to store cable and a quick test for stock that has been sitting.
On This Page
| Part | Aging mechanism | Result |
|---|---|---|
| PVC jacket | Plasticizer migrates out, UV and heat embrittle | Stiff, cracked jacket |
| Polyethylene dielectric | Slow oxidation, moisture | Higher loss if wet |
| PTFE / FEP | Chemically inert | Essentially no aging |
| Copper braid (bare) | Oxidizes, green and black corrosion | Higher shield resistance |
| Silver-plated braid | Tarnishes but conducts | Cosmetic, solderability drops |
| Connectors | Tarnish, corrosion in humidity | Higher contact resistance |
Key idea: Moisture ingress at a cut or damaged end is the worst enemy. Water wicks along the braid and degrades dielectric and conductors far from the damage.
| Cable | Jacket and dielectric | Typical shelf life indoors |
|---|---|---|
| RG58, RG174 (PVC / PE) | PVC and PE | 10 to 20 years, less in heat |
| RG213, LMR with PE jacket (UV rated) | PE | 15+ years outdoors if sealed |
| RG316, RG402 (FEP / PTFE) | FEP and PTFE | Decades; very stable |
| Low-cost CCA braid cable | PVC | Shorter; corrosion starts early |
These ranges are rules of thumb from storage and field experience, not guaranteed life. Heat, sun and moisture shorten them.
Use assemblies swept before shipment
Every SigmaRF assembly is VNA-swept for VSWR and insertion loss before shipment, so you know the numbers from day one.
Talk to an EngineerGood storage
What shortens life
Check 01
Inspect the jacket and ends
Look for cracks, chalking, green corrosion on the braid and connector tarnish.
Check 02
Flex test
Bend gently. If the jacket cracks or feels brittle, retire it.
Check 03
DC continuity and shorts
Check center-to-center and shield-to-shield, and look for center-to-shield shorts.
Check 04
VNA sweep
Measure S11 and S21 across your band. Compare to a new sample. A TDR shows damage location.
Can coaxial cable go bad over time?
Yes. PVC jackets harden and crack, braid corrodes and moisture damages the dielectric. PTFE cables age very slowly.
How long does coax cable last?
Indoors, PVC cable commonly lasts 10 to 20 years. Outdoors, UV-rated cable can last 15 or more years if sealed. PTFE cable can last decades.
Does unused coax cable degrade in storage?
Slowly. Keep it cool, dry, sealed and out of sunlight.
How do I know if coax is bad?
Look for cracks, corrosion and stiffness, then check return loss and insertion loss on a VNA.
Does coax cable lose signal over time?
Loss rises if the braid corrodes or water enters. A dry, intact cable keeps its loss.
Which coax lasts longest?
PTFE and FEP cables like RG316 and RG402, and semi-rigid cable.
Coax does not wear out from carrying signal. It ages from sun, heat, moisture and flexing. Choose the right jacket for the environment, seal the ends and test old stock before you trust it.
SigmaRF builds assemblies with PTFE and FEP cable in India (Vadodara) and the USA (Cleveland area), VNA-swept before shipment, with lead times as short as 2 days.
Need fresh assemblies?
Standard or custom, swept before shipment.
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