Case Study: Troubleshooting Wireless Links in the Himalayas

Direct Media Pvt. Ltd. is expanding connectivity to rural mountain areas where reliable internet access is still scarce. One of our projects involves distributing internet from our city office tower to a remote mountain site. The site is connected through a 7.2 km line-of-sight wireless backhaul using Ubiquiti equipment.

A transformer failure in the village recently caused permanent damage to our PowerBeam radio at the mountain site, as well as to equipment from other ISPs. This unexpected failure forced us to re-evaluate, replace, and test different radios under real-world conditions.

Challenge

• Replace the damaged PowerBeam with a LiteBeam at the mountain site.
• Ensure stable connectivity between the city office tower and the mountain distribution site.
• Overcome obstacles such as limited working hours (remote location, darkness, and difficult terrain).
• Evaluate redundancy with TP-Link CPE510 radios.

Approach

1. Initial Attempt (Unsuccessful)

• Installed the LiteBeam to replace the PowerBeam at the original location.
• Unable to detect the SSID of the PowerBeam AP on the city tower.
• Limited daylight forced us to abandon testing and return.

2. Second Attempt (Detailed Testing)

• Reached the site early (40-minute drive, winding mountain road).
• Reinstalled the LiteBeam with better alignment.
• Added a pair of TP-Link CPE510 radios as backup to connect with another CPE510 on the office tower.

3. Field Testing Results

• LiteBeam → PowerBeam: Initially, no SSID detected at the original mountain site.
• CPE510 → CPE510: Achieved 15 Mbps down / 6 Mbps up link, but no usable internet.
• Suspected Fresnel zone obstruction at the first location.

4. Alternative Location

• Dismantled both LiteBeam and CPE510 and tested from another site with clear line of sight.
• LiteBeam connected immediately to the PowerBeam AP.
• CPE510 and Lite AP could detect SSID but still failed to provide working internet.
• The successful LiteBeam connection confirmed the radio itself was functional.

Outcome

• Verified that line of sight and Fresnel zone clearance were the primary challenges at the original site.
• LiteBeam performed reliably once installed at a location with clear LOS.
• TP-Link CPE510 provided some connectivity but with low throughput and no internet routing, reinforcing the importance of choosing the right equipment for distance and conditions.
• The community was encouraged by the progress and interested in the expansion of internet service.

Lessons Learned

1. Redundancy is valuable — testing with both Ubiquiti and TP-Link radios gave us fallback options.

2. Fresnel zone clearance matters — even with strong radios, partial obstructions can severely impact performance.

3. On-site testing is essential — theoretical coverage maps are useful, but real-world terrain and obstacles can change outcomes.

4. Plan for resilience — sudden equipment damage (like the transformer incident) highlights the need for backup gear and diversified vendor solutions.

Conclusion

This case study reflects the real challenges WISPs face in rural deployments. The terrain, power infrastructure, and time constraints all play a role in how quickly connectivity can be restored. By combining experience, redundancy planning, and persistence, Direct Media Pvt. Ltd. is steadily expanding reliable internet access to underserved areas in the Himalayas.