POP Module 4 - Wireless Basics

Wireless Alignment and Optimization

Learn wireless fundamentals, sector antenna operation, LiteBeam alignment techniques, signal optimization tools, and troubleshooting connectivity issues

Learning Objectives

By the end of this module, you will be able to:

Understand how wireless signals propagate in rural agricultural settings
Identify the role of the Rocket M2 sector antenna at the hub building
Perform precise LiteBeam alignment using signal strength feedback
Use alignment tools and mobile apps to optimize connectivity
Troubleshoot common connectivity issues including interference and weather impacts
Maintain stable, high-performance wireless links over time

Wireless Fundamentals in Rural Settings

Understanding how radio signals travel and what affects connectivity

 

The POP system uses point-to-point (PtP) wireless technology to create a "backhaul" link between the main building and the remote trailer. Understanding how these signals work is essential for successful deployment and troubleshooting.

 

Key Wireless Components

Line-of-Sight (LOS) Propagation

Understanding Wireless Signal Fundamentals for POP Deployments

Definition: Radio waves at 5 GHz (used by LiteBeam) travel in essentially straight lines, similar to light. They cannot bend around obstacles like lower frequencies can.

Why LOS Matters

  • Clear path required: Any obstruction in the path blocks or severely weakens the signal
  • Height advantage: Elevating antennas (via mast) improves LOS by clearing ground-level obstacles
  • Earth curvature: At distances >5 km, Earth's curvature becomes a factor (not typical for POP deployments)
  • Fresnel zone: Area around the direct path that must also be mostly clear (80%+ clearance ideal)

✅ Good LOS Conditions

  • Flat terrain or gentle slopes
  • No trees/buildings in path
  • Clear visibility between antennas
  • Elevated antenna positions

❌ Poor LOS Conditions

  • Hills or ridges blocking path
  • Dense tree canopy in path
  • Buildings obstructing view
  • Low antenna height

Signal Strength and Quality

Signal strength is measured in dBm (decibels relative to one milliwatt). This is a logarithmic scale where more negative numbers mean weaker signals.

Signal Strength Reference Chart:

-38 to -50 dBm
Excellent
-51 to -58 dBm
Very Good
-61 to -75 dBm
Good
-76 to -85 dBm
Fair
-86 to -95 dBm
Poor
< -95 dBm
Unusable
Target for POP Deployments:
Aim for -50 to -65 dBm signal strength during alignment. This provides excellent performance with margin for weather variations and seasonal changes.

Frequency and Bandwidth

Backhaul Link (Hub ↔ POP)

  • Frequency: 5 GHz (5.15-5.8 GHz)
  • Equipment: Rocket M2 + LiteBeam 5AC
  • Range: Up to 5 km (line-of-sight)
  • Bandwidth: 50-300 Mbps typical
  • Characteristics: High speed, LOS required, weather sensitive

Local WiFi (POP ↔ Devices)

  • Frequency: 2.4 GHz + 5 GHz dual-band
  • Equipment: U6 Mesh Pro / E7 Campus
  • Range: 50-80 m radius (open field)
  • Bandwidth: Shared among all connected devices
  • Characteristics: Wider coverage, penetrates obstacles better
💡 Why Different Frequencies?
Using 5 GHz for the backhaul link and dual-band (2.4/5 GHz) for local WiFi prevents interference between the two systems. The backhaul operates on different channels than the access points, ensuring maximum performance for both.

Environmental Factors

Weather Effects

  • Rain: Can attenuate 5 GHz signals by 1-3 dB in heavy downpours (usually not critical)
  • Fog: Minimal effect at 5 GHz
  • Snow/Ice: Can accumulate on antennas, blocking signal (rare in NM, but possible)
  • Wind: Can cause antenna misalignment if mounting hardware loosens
  • Temperature: Extreme heat/cold can affect equipment performance

Vegetation

  • Trees: Major obstacle—even bare branches cause significant signal loss
  • Foliage: Leaves contain water, which absorbs 5 GHz signals heavily
  • Seasonal changes: Link that works in winter may fail in summer when trees leaf out
  • Crops: Tall crops (corn, sorghum) can partially block signals at ground level

Interference Sources

  • Other WiFi networks: Nearby access points on same channels
  • Radar: Weather radar and military installations (can force channel changes)
  • Microwave ovens: Operate at 2.4 GHz (affects WiFi, not 5 GHz backhaul)
  • Bluetooth devices: Also 2.4 GHz, minor interference potential

Key Takeaways for POP Deployments

1 Line-of-sight is critical—without it, the link won't work reliably
2 Height improves coverage—the 21-foot mast helps clear obstacles
3 Target -50 to -65 dBm signal strength for optimal performance
4 Weather and vegetation can affect signal quality—plan accordingly
5 Precise alignment matters—even small misalignments reduce performance significantly
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