Choosing the Proper RF Cables for Reliable LoRaWAN® Networks

Are you facing connectivity drops, reduced coverage, or increasing maintenance costs in your outdoor LoRaWAN® network?

These issues might trace back to one often-overlooked component: the RF cables and connectors linking your gateways and antennas. Deploying a reliable outdoor LoRaWAN® network means ensuring every part—from gateways and antennas to RF cables and connectors—can withstand the elements and function optimally over time.

The Challenge of Outdoor Environments

Outdoor LoRaWAN® deployments endure extreme conditions: rain, snow, freezing temperatures, UV sunlight, sand, and relentless winds. This harsh environment is unforgiving, especially for RF cables and connectors, leading to moisture ingress, corrosion, and other factors that can degrade your network’s performance and increase costs.

Did you know that moisture inside RF connectors and cables is one of the top reasons for signal loss, coverage reduction, and equipment failure?

Here’s a breakdown of the key issues and how the right RF cable choices can help you avoid these pitfalls.

Key Issues Caused by Moisture in RF Connectors and Cables

Choosing the Right Cable for Longevity and Performance

Selecting the right RF cables can mean the difference between seamless, reliable performance and frequent, costly maintenance. To ensure reliable network operation over 10-15 years—without degradation or constant site visits—it’s crucial to choose cables with high RF performance that can withstand extreme weather conditions.

Outdoor environments expose cables to relentless challenges: rain, snow, ice, freezing temperatures, heat exceeding +65°C, UV sunlight, dust, sand, and high winds. Only the best RF cable assemblies, equipped with plated N-type connectors that are over-molded or sealed with the cable housing, can prevent moisture from penetrating between the cable and connector.

Are your RF cables truly ready for the long haul in outdoor LoRaWAN® deployments?

These top-quality cables, especially those in lengths of 1-3 meters, are often comparable in cost to other RF cables, yet they’re designed to endure the elements without degradation. They withstand harsh environments and guarantee 10-15 years of consistent network performance. Additionally, they are easy to weatherize using Butyl tape or telecom-grade silicone, allowing for protection of the connector interfaces without impacting the cable assembly itself.

After reviewing the key features of durable RF cables, you now understand how choosing the right assemblies can safeguard your network from harsh conditions and ensure long-lasting performance.

Let’s explore the types of RF cables commonly used and how they stack up for outdoor LoRaWAN® deployments.

RF cable assemblies come with plated N-type connectors and over-molded housing

There are three common RF cable types on the market today, specifically RG, LMR and Heliax, that many LoRaWAN® operators use in their deployments.

RG Cables

• Background: Originally developed during World War II for military applications, RG cables have limited RF properties and are not suitable for outdoor, long-term use.

• Limitations: These cables lack UV resistance and are highly susceptible to moisture intrusion, leading to increased signal loss, impedance mismatches, and corrosion over time.
• Expected Lifespan: Typically, under 5 years when used outdoors, RG cables degrade quickly in harsh conditions and are best avoided for any outdoor LoRaWAN® deployments expected to last more than 3-5 years.
• Recommendation: RG cables may be suitable for low-power, indoor applications but are not recommended for outdoor LoRaWAN® use.

LMR Cables (e.g., LMR-400)

• Background: Known as “Low Loss RF” cables, LMR cables were originally designed for two-way radio systems used in public safety and military communications.

• Strengths: LMR cables feature a UV-resistant polyethylene jacket, making them more suitable for outdoor use than RG cables. They also offer low RF signal loss, which is crucial for longer cable runs.
• Considerations: The connector assembly and weatherization for LMR cables require careful installation. While the braided RF shield is applied over the N-type connectors and crimped, this assembly is less robust than the over-molded connectors in Heliax cables.
• Expected Lifespan: With proper installation and weatherproofing, LMR cables can provide dependable service for up to 10 years in most climates.
• Recommendation: LMR cables are a solid choice for shorter outdoor deployments or where budget constraints exist, though they will not match the durability of Heliax cables.

Heliax Cables (e.g., AVA5-50)

• Background: Heliax cables are known for their superior durability and extremely low attenuation, making them ideal for high-performance applications and harsh outdoor conditions.

• Strengths: These cables feature a corrugated outer conductor and high-quality materials, offering strong resistance to environmental stress, including extreme cold, heat, and UV exposure. The tight connection between the N-type connector and the corrugated outer RF shield enhances resilience.
• Expected Lifespan: Heliax cables can easily exceed 15 years in harsh environments, often lasting up to 20 years or more.
• Recommendation: For high-performance, long-term outdoor LoRaWAN® deployments, Heliax cables are the top choice. They are optimized for maintaining signal strength and are highly reliable over time.

Recommendation Summary

For outdoor LoRaWAN® deployments expected to last 10 to 15 years, Heliax cables are the best choice due to their:

• extreme durability,
• superior RF performance,
• longevity.

Several suppliers offer Heliax-type cables, and it is recommended to choose cables with corrugated outer conductors for enhanced resilience.

LMR cables, especially the LMR-400, are a suitable alternative when budget constraints are present, though they do not offer the same lifespan and resilience as Heliax cables.

For cables that are 1-3 meters in length, the cost difference between Heliax and LMR-400 cables is minimal, as connectors and assembly are the main cost factors.

Step-by-Step Guide to Weatherproofing RF Cable Assemblies

To weatherproof connections between antennas and Heliax or LMR cables, use the right sealant materials and apply them correctly. Installers without prior experience should practice applying the sealant and telecom tape multiple times on the ground to determine the optimal amount, as this process can be challenging when applied on antennas mounted on towers.

Preventing moisture ingress is essential for maintaining RF cable performance and network reliability. Any moisture within RF cables degrades LoRaWAN® performance through signal loss, corrosion, and impedance changes, all of which compromise system reliability and may lead to failure.

Step 1. Prepare the Connector Area

• Clean the Surfaces: Ensure both the antenna and RF cable connectors are clean and free from dust, oils, or contaminants that could affect sealant adhesion.
• Inspect the Connector: Check that connectors are tightly mated and torqued according to manufacturer specifications to ensure a solid mechanical and electrical connection.

Step 2. Apply Butyl Tape

• Wrap the Tape: Start at the antenna base and wrap butyl tape around the connector, extending onto the cable jacket. Cover the entire length of the exposed connector and at least 2-3 cm of the cable housing.
• Stretch and Press: As you wrap, gently stretch the butyl tape to ensure it adheres tightly to the connector contours and cable housing. Press down firmly to eliminate air gaps, and slightly overlap each layer for a thick, uniform seal around the entire circumference.

Step 3. Apply Telecom-Grade Silicone or Tape

• Cover with Silicone or Tape: Apply a layer of telecom-grade silicone sealant over the butyl tape or use telecom tape to further weatherproof the connection. Extend the sealant slightly beyond the butyl tape edges onto the cable jacket and antenna base to ensure complete coverage. Many telecom-grade silicone options are available from vendors on Amazon, Alibaba, and similar sites.

Silicone or telecom tape acts as an additional moisture barrier and UV shield for the butyl tape, preventing degradation from prolonged sun exposure.

To remove the butyl tape from the weatherproofed assembly, carefully cut it with an exact knife, then peel it off and clean the cable and connectors.

Why Moisture Protection is Critical

Moisture entering RF cables can lead to several critical issues:

• Corrosion and Oxidation: Moisture inside connectors can corrode and oxidize metal contacts, reducing conductivity and increasing resistance at the connection point.
• Increased Signal Loss: Water causes impedance mismatches, resulting in signal loss and reduced transmission efficiency. This is especially problematic in LoRaWAN® systems, where even minor signal degradation can impact network reliability.
• Permanent Damage to Dielectric Material: In cables like Heliax, moisture can permanently damage the dielectric material, altering the cable’s impedance and causing irreversible performance loss.
• Increased Maintenance and Replacement Costs: Poor weatherproofing leads to frequent failures, resulting in higher maintenance costs, downtime, and potential disruptions in network availability.

Properly weatherproofing with butyl tape and telecom-grade silicone creates a moisture-resistant seal, maximizing the reliability and lifespan of your LoRaWAN® installation in challenging outdoor environments.

Moisture Effects on LoRaWAN® Network Performance and Quality of Service

• Coverage Reduction: Signal loss and reflections can cause devices at the network edge to lose connectivity, decreasing overall reach.
• Increased Packet Loss and Retries: Poor signal quality and noise lead to packet loss, requiring retransmissions that consume additional bandwidth and network resources.
• Lower Data Integrity and SNR: Noise and interference distort data transmission, causing packet corruption and reducing service quality.
• Higher Maintenance and Replacement Costs: Corrosion, dielectric damage, and physical wear increase maintenance and replacement needs, impacting operational costs.
• Reliability Issues: As connection reliability degrades, overall network performance and quality of service decline, impacting user experience and application success.

Preventing moisture ingress is essential for maintaining reliable LoRaWAN® network performance and delivering the quality expected in a Carrier Grade deployment.

Ready to optimize your LoRaWAN® network for long-term reliability? Contact us today info@tektelic.com for expert guidance on selecting the right RF cables and weatherproofing solutions. Our team is always here to provide consultations and share our extensive industry expertise.