Antennas, Antenna Cables, Wireless Products: Technical Articles
Heat Shrink Tubing for Antenna Cables: Types, Tips, Sizing
For antenna cables made with LMR-100, LMR-200 and LMR-400 coaxial cable, adhesive-lined heat shrink tubing is generally better than standard (non-lined) tubing. Here's why:
Adhesive-Lined Heat Shrink Tubing: Recommended
Advantages:
Moisture Seal: The internal adhesive melts and flows during shrinking, creating a watertight seal around both the connector and the cable jacket.
Strain Relief: Provides better mechanical support at the junction between the cable and connector, minimizing risk of damage from movement or vibration.
Environmental Protection: Especially useful for outdoor antenna cables, as it blocks out dust, dirt, and UV exposure.
Longer-Term Durability: It resists thermal cycling, ensuring the seal holds in both hot and cold environments.
Best Use Case:
Outdoor or semi-exposed environments
Where water ingress or corrosion is a concern (e.g., rooftops, towers, marine setups)
Standard (Non-Lined) Heat Shrink Tubing: Limited Use
Advantages:
Easier to apply and slightly cheaper
Works fine in indoor or controlled environments
Can be sufficient if you use other sealing methods (like tape or weatherproof boots)
Disadvantages:
Does not provide a moisture barrier
Can allow air and moisture to seep in, leading to oxidation or RF leakage over time
Practical Tip:
Choose a tubing with:
3:1 shrink ratio to ensure tight fit around the cable and connector
UV resistance if used outdoors
Sufficient length to cover part of the connector and extend onto the cable jacket for secure adhesion
Summary Conclusion
Adhesive-lined heat shrink tubing is the superior choice for sealing and protecting LMR-200/400 cables with SMA and Type N connectors, particularly in outdoor or mission-critical RF applications.
Recommended Heat Shrink Tubing Sizes for Coaxial Antenna Cables
| Coax Cable Type | Nominal Cable Diameter | Recommended Tubing (Before Shrink) | Recommended Tubing (After Shrink) | Shrink Ratio | Notes |
|---|---|---|---|---|---|
| LMR-100 | 0.10 in (2.5 mm) | 3/16 in (4.8 mm) | 0.0625 in (1.6 mm) | 3:1 | Light-duty pigtails, GPS leads |
| LMR-195 / RG58 | 0.195 in (4.95 mm) | 1/4 in (6.4 mm) | 0.08 in (2 mm) | 3:1 | Wi-Fi / LTE cables |
| LMR-200 | 0.195 in (4.95 mm) | 1/4 in (6.4 mm) | 0.08 in (2 mm) | 3:1 | Slightly more rugged than LMR-195 |
| RG-6 | 0.27 in (6.9 mm) | 3/8 in (9.5 mm) | 0.12 in (3 mm) | 3:1 | Often used for TV antennas |
| LMR-240 | 0.24 in (6.1 mm) | 3/8 in (9.5 mm) | 0.12 in (3 mm) | 3:1 | Moderate-power RF uses |
| LMR-400 | 0.405 in (10.3 mm) | 1/2 in (12.7 mm) or 3/4 in (19 mm) | 0.17 in (4.5 mm) to 0.25 in (6.4 mm) | 3:1 | Heavy-duty outdoor cable |
| LMR-600 | 0.59 in (15 mm) | 3/4 in (19 mm) to 1 in (25 mm) | 0.25 in (6.4 mm) to 0.33 in (8.5 mm) | 3:1 | High-power runs, long lengths |
| RG-213 / RG-214 | 0.405 in (10.3 mm) | 1/2 in (12.7 mm) or 3/4 in (19 mm) | 0.17 in (4.5 mm) to 0.25 in (6.4 mm) | 3:1 | Shielded mil-spec coax |
| RG-8X (Mini-8) | 0.242 in (6.15 mm) | 3/8 in (9.5 mm) | 0.12 in (3 mm) | 3:1 | HF radio and marine use |
Adhesive-lined tubing ensures a weatherproof, tight bond with both the connector and cable jacket.
Select a tubing that is just large enough to slide over the connector but will shrink tightly around the cable.
Use a heat gun, not an open flame, to activate the adhesive and ensure even shrinkage.
For long-term outdoor use, choose tubing that is UV-stabilized and rated for -55°C to 125°C.
Materials Used in Heat Shrink Tubing for Antenna Cables
The material composition of heat shrink tubing for antenna cables—especially when used for outdoor RF connectors like SMA, N-Type, RP-SMA, TNC, and LMR-series coax—is critical for ensuring weather resistance, UV durability, and electrical insulation. Here's a breakdown of the most common materials used:
| Material | Typical Use | Key Properties | Applications |
|---|---|---|---|
| Polyolefin (cross-linked) | Most common heat shrink tubing | - Excellent insulation - UV and chemical resistance - Shrinks uniformly | General-purpose, indoor/outdoor cable sealing |
| Adhesive (hot melt glue) | Inner lining in dual-wall tubing | - Seals out moisture and dust - Bonds to plastic, rubber, and metal | Outdoor weatherproofing, marine, telecom |
| Fluoropolymer (e.g., PTFE, FEP, PVDF) | High-performance tubing | - High-temp (up to 200–250°C) - Chemically inert - Non-stick surface | Aerospace, military, extreme weather |
| Elastomeric polyolefin or Neoprene | Flexible and oil-resistant use | - Rubber-like stretchability - Good abrasion resistance | Strain relief for high-flex installations |
| Silicone Elastomer | High-flex, high-temp settings | - Very flexible - Temp resistance to ~200°C | Special RF/microwave use (less common) |
Dual-Wall Adhesive-Lined Polyolefin Tubing
This is the go-to tubing for outdoor antenna connectors due to:
Outer Layer: Cross-linked polyolefin
Shrinks uniformly
Resists UV, water, and abrasion
Inner Layer: Thermoplastic adhesive (hot melt glue)
Flows when heated and seals tightly
Bonds to connector knurling and cable jacket
Typical shrink ratio: 3:1 or 4:1
Temperature rating: -55°C to +125°C
Dielectric strength: ~15–25 kV/mm
Adhesive melt point: 80–110°C
Why Polyolefin Is Ideal for Antenna Cables
RF-Safe: Does not interfere with signal
Environmental Durability: Resistant to UV, rain, snow, and ozone
Mechanical Protection: Protects against cable flex and pull-out
Chemical Resistance: Handles fuels, oils, and cleaning solvents
Notes
Use UV-resistant tubing if cable will be exposed to sunlight continuously.
For marine or desert environments, choose tubing labeled MIL-DTL-23053/4 or similar military-grade spec.