Picking the Ideal RF Cables for Dependable LoRaWAN® Network Operations

Picking the Ideal RF Cables for Dependable LoRaWAN® Network Operations

Confronting issues like frequent connectivity drops, reduced coverage, and escalating maintenance costs in your outdoor LoRaWAN network? These problems could be linked to a commonly overlooked part: the RF cables and connectors connecting your gateways and antennas.

Establishing a resilient outdoor LoRaWAN network necessitates ensuring every component, from gateways and antennas to RF cables and connectors, can withstand the elements and maintain optimal performance over time.

The Trials of Outdoor Environments

Outdoor LoRaWAN deployments encounter extreme conditions: rain, snow, freezing temperatures, UV sunlight, sand, and relentless winds. This unforgiving environment can take a toll, particularly on RF cables and connectors, leading to moisture ingress, corrosion, and other degrading factors affecting network performance and boosting costs.

It is essential to know that moisture within RF connectors and cables is one of the leading causes of signal loss, coverage reduction, and equipment failure.

Issue

Here's a breakdown of the primary issues and how choosing the right RF cable can help you dodge these pitfalls:

Impact

Primary Problems Caused by Moisture in RF Connectors and Cables

Effect on Network

| | | || --- | --- | --- || Issue | Impact | Effect on Network || 1. Amped Signal Loss | Moisture intensifies signal loss in RF cables, weakening the signal strength towards the antenna or receiver. | Lessened range and coverage demand extra gateways, boosting deployment costs. Devices farther from gateways may find it challenging to connect, lowering network reliability. || 2. Impasse Impedance and Reflections | Water alters dielectric properties, causing impedance mismatches and signal reflections. | Reflections result in erratic communication and packet loss, especially in minimal-signal zones, degrading reliability and bumping up data retry rates. || 3. Connector and Contact Corrosion | Moisture corrodes metal contacts, upping resistance and hastening damage to connectors. | Corrosion causes signal drops and packet loss, leading to more frequent communication interruptions and costly maintenance or replacements. || 4. Noise and Interference | Moisture adds noise within cables, disrupting signals and introducing interference. | Noise lowers Signal-to-Noise Ratios (SNR), resulting in data corruption, retransmissions, and shorter device battery life. || 5. Damage to Dielectric Material | Prolonged moisture exposure damages dielectric material, altering cable impedance and signal properties. | Dielectric damage reduces coverage and reliability, frequently necessitating costly replacements due to heightened signal loss. || 6. Condensation and Freezing Expansion | In cold climates, trapped moisture can freeze, expanding and damaging cables and connectors. | Physical damage from freezing leads to further signal issues, increased maintenance costs, and potential service outages until repairs are done. |

Choosing a Cable for Durability and Performance

1. Increased Signal Loss (Attenuation)

Deciding on the right RF cables can mean the difference between seamless, dependable performance and constant, costly maintenance. To ensure constant network functionality over 10-15 years without degradation or frequent site visits, it's crucial to select cables with high RF performance capable of enduring extreme weather conditions.

Moisture raises signal loss in RF cables, weakening signal strength to the antenna or receiver.

Outdoor surroundings challenge cables with rain, snow, ice, freezing temperatures, high heat, UV sunlight, dust, sand, and extreme winds. Only the finest RF cable assemblies, equipped with plated N-type connectors and over-molded or sealed cable housing, can bar moisture from penetrating between the cable and connector.

Reduced range and coverage require more gateways, increasing deployment costs. Devices further from gateways may struggle to connect, lowering network reliability.

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

These high-quality cables, especially in lengths of 1-3 meters, are generally on par with the cost of other RF cables but are engineered to tolerate harsh environments without degradation. They uphold stable network performance and withstand extreme conditions for 10-15 years. Moreover, they can be effortlessly weatherized using Butyl tape or telecom-grade silicone, allowing for the protection of connector interfaces without adversely affecting the cable assembly itself.

2. Impedance Mismatch and Reflections

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

Water alters dielectric properties, causing impedance mismatches and signal reflections.

Delving into RF Cable Types Commonly Used and Their Suitability for Outdoor LoRaWAN Deployments

Reflections lead to erratic communication and packet loss, especially in low-signal areas, degrading reliability and increasing data retry rates.

RF Cable Assemblies With Plated N-type Connectors and Over-molded Housing

Several kinds of RF cable assemblies prevailing in the market today, notably RF, LMR, and Heliax, are commonly employed in LoRaWAN deployments. Here's a look at these options and how they stack up in outdoor LoRaWAN deployments:

3. Corrosion of Connectors and Contacts

RG Cables

Moisture corrodes metal contacts, increasing resistance and speeding up damage to connectors.

• Background: Originated during WWII for military applications, RG cables have limited RF properties and are less suitable for prolonged outdoor use.
• Limitations: These cables lack UV resistance and are highly susceptible to moisture ingress, gradually causing signal loss, impedance mismatches, and corrosion over time.
• Lifespan: Typically, under 5 years when utilized outdoors, RG cables deteriorate swiftly in adverse conditions and should be avoided for outdoor LoRaWAN deployments projected to last more than 3-5 years.
• Recommendation: RG cables might be suited for low-power, indoor applications but are not recommended for outdoor LoRaWAN use.

Corrosion causes signal drops and packet loss, leading to more frequent communication failures and costly maintenance or replacements.

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

• Background: Known as "Low Loss RF" cables, LMR cables were initially designed for two-way radio systems used in public safety and military communications.
• Strengths: LMR cables boast a UV-resistant polyethylene jacket, making them more suitable for outdoor use compared to RG cables. They also offer low RF signal loss, vital for longer cable runs.
• Considerations: 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.
• Lifespan: With proper installation and weatherproofing, LMR cables can provide dependable service for up to 10 years in most climates.
• Recommendation: LMR cables represent a solid choice for shorter outdoor deployments or where budget constraints exist, though they will not match the durability of Heliax cables.

4. Noise and Interference

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

Moisture adds noise within cables, disrupting signals and introducing interference.

• Background: Heliax cables are renowned for their extraordinary strength and exceptionally 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, providing powerful 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 bolsters resilience.
• Lifespan: Heliax cables can easily surpass 15 years in harsh environments, frequently lasting 20 years or more.
• Recommendation: In high-performance, long-term outdoor LoRaWAN deployments, Heliax cables are the preferred choice. They are optimized for maintaining signal strength and are highly dependable over time.

Noise reduces Signal-to-Noise Ratios (SNR), causing data corruption, retransmissions, and shorter device battery life.

Conclusion

For outdoor LoRaWAN deployments predicted to last 10 to 15 years, Heliax cables are the optimal choice due to their:

5. Damage to Dielectric Material

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

Prolonged moisture exposure damages dielectric material, altering cable impedance and signal properties.

Numerous suppliers offer Heliax-type cables, and it's recommended to pick cables with corrugated outer conductors for enhanced resilience.

Dielectric damage reduces coverage and reliability, often necessitating costly replacements due to increased signal loss.

LMR cables, especially the LMR-400, offer a suitable alternative when budget constraints are present, though they cannot match the longevity and toughness of Heliax cables.

For cables measuring 1-3 meters in length, the cost difference between Heliax and LMR-400 cables is minimal, as connectors and assembly account for the primary cost factors.

6. Condensation and Freezing Expansion

Weatherproofing RF Cable Assemblies

In cold climates, trapped moisture can freeze, expanding and damaging cables and connectors.

To shield connections between antennas and Heliax or LMR cables, use suitable sealant materials and apply them correctly. Installers lacking 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.

Physical damage from freezing leads to further signal issues, higher maintenance costs, and potential service outages until repairs are made.

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 network reliability and may lead to failure.

Step 1. Prepare the Connector Region

• 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: Confirm connectors are firmly mated and torqued 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 such as Amazon, Alibaba, and similar sites.

Silicone or telecom tape acts as an additional moisture barrier and UV shield for the butyl tape, preventing degradation due to 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.

The Crucial Importance of Moisture Protection

Moisture penetrating RF cables can cause 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 irreversibly damage the dielectric material, altering the cable's impedance and causing permanent performance loss.
• Increased Maintenance and Replacement Costs: Poor weatherproofing results in frequent failures, causing 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.

The Impact of Moisture 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, necessitating 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 crucial 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@our website for expert advice on selecting the right RF cables and weatherproofing solutions. Our team is always here to offer consultations and share our extensive industry expertise.

[4] LoRa Alliance. "Specifying a LoRaWAN® Network." LoRaWAN® Certification Guide. v1.0.0. September 2020. Link to source

1. The harsh outdoor environment experienced by LoRaWAN networks can negatively impact RF connectors and cables, often leading to moisture ingress, corrosion, and other degrading factors.
2. Amped signal loss, impedance mismatches, connector and contact corrosion, noise and interference, damage to dielectric material, condensation, and freezing expansion are the primary problems caused by moisture in RF connectors and cables, significantly affecting network performance and potentially increasing costs.
3. Selecting high-quality, long-lasting RF cable assemblies with plated N-type connectors, over-molded or sealed cable housing, and capable of enduring extreme weather conditions is essential for outdoor LoRaWAN deployments aimed at maintaining seamless, dependable performance and minimizing frequent, costly maintenance.

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