The sheathing (outer jacket) of a coaxial cable for antennas is one of the most important (and sometimes underestimated) factors in signal performance, durability, and environmental reliability.

This article covers materials, ratings, and best applications for antenna feedlines and pigtails — so you can match the right jacket to your use cases (indoor, outdoor, mobile, marine, IoT, etc.).

1. What the Sheathing (Outer Jacket) Does

The sheath (or outer jacket) is the final protective layer of a coaxial cable, surrounding the shield and dielectric. Its functions:

• Environmental protection (UV, moisture, chemicals)

• Mechanical strength (abrasion, crushing, flexing)

• Electrical insulation

• Temperature resistance

• Flexibility and handling characteristics

It does not carry current or affect impedance directly — but it protects the layers that do.

2. Common Coaxial Sheathing Materials

3. Typical Sheath for Popular Coax Families

4. Outdoor and UV Considerations

For antenna cables exposed to sun and weather, the sheath material choice is critical:

• UV Resistance:

  • PE, FR-PE, and TPE are highly UV-stable.

  • PVC will crack and become brittle within a year or two in full sun.

• Moisture Ingress:

  • PE resists water absorption almost completely.

  • PVC absorbs slight moisture; use only indoors or inside sealed enclosures.

• Temperature Range:

  • PE: –40 °C to +80 °C typical

  • TPE: –50 °C to +105 °C

  • FEP: –65 °C to +200 °C

  • PVC: –20 °C to +70 °C (stiffens in cold)

5. Mobile / Rugged / IoT Applications

For IoT, vehicle-mounted, or mobile antennas, the ideal jacket is usually TPE or PUR, because:

• They remain flexible in cold and resist cracking in vibration.

• They tolerate oils, fuels, and outdoor conditions.

• They can handle flexing thousands of times without splitting.

If your IoT devices are outdoors or subject to vibration, choose LMR-240UF (UltraFlex) or LMR-195UF, which use TPE jackets and stranded center conductors.

6. Indoor vs. Outdoor Recommendations

7. Special Features to Look For

• Direct-burial rated: For underground runs; jacket resists moisture and microbes.

• Dual jacket: Some cables add an inner PVC for flexibility + outer PE for weatherproofing.

• Plenum / Riser ratings: For building code compliance (CMP, CMR).

• Abrasion resistance: For cables passing through metal or rough surfaces.

8. Summary Table: Sheath Materials vs. Key Traits

9. Recommendations for Antenna Use

First Line of Defense

The outer sheath is the first line of defense for coax reliability. For antenna applications — especially in sunlight, temperature swings, or vibration — avoid standard PVC jackets. Use UV-rated PE or flexible TPE/PUR depending on your needs.

Conclusion

The outer sheathing of an antenna cable is far more than a cosmetic covering — it’s the cable’s primary defense against the environment and mechanical stress. The right jacket material ensures long-term signal reliability, mechanical strength, and resistance to UV, moisture, and chemicals. For outdoor and mobile antenna systems, materials like PE, FR-PE, TPE, and PUR outperform PVC in durability and weather resistance. Matching the sheath type to the installation — indoor, outdoor, marine, or industrial — maximizes both cable life and signal integrity. In short, choosing the proper sheathing is key to protecting your investment and maintaining consistent antenna performance over time.