Mobile network fault resolution at a chimney site
8. May 2026
A mobile network site on a chimney, an out-of-service sector and difficult access: our team was deployed to a site in Meißen to investigate a technical fault and resolve its underlying cause.
It was clear from the outset that this would be no routine assignment. The affected equipment was installed on a chimney that was difficult to access. At the same time, precise technical testing was needed to pinpoint the fault and restore coverage as quickly as possible.
Systematic on-site troubleshooting
First, our team examined the affected equipment on site. They found that the signal level reaching the remote radio unit (RRU) on the chimney was too low. Measurements in the equipment room, however, showed an adequate transmit signal level at the baseband unit (BBU).
This finding was crucial, as it allowed several potential fault sources to be ruled out early on. The fibre-optic link was also checked during the investigation. This included a comparative measurement using an optical time-domain reflectometer (OTDR). Initially, this measurement revealed no abnormalities.
Restarting the remote radio unit made no difference either. As the investigation continued, however, the symptoms changed: communication with the affected unit was eventually lost, and the associated sector remained out of service.
Working under challenging conditions
Access to the installation presented a further challenge alongside the technical investigation. The chimney’s access ladder was closed to use, and site conditions ruled out a mobile elevating work platform. An alternative means of access therefore had to be arranged before work could continue safely.
With the help of a crane, our team was finally able to work directly on the equipment installed on the chimney. Further tests were carried out there to narrow down the cause. Repeat measurements of the fibre-optic link between the equipment room and the equipment on the chimney showed insertion loss within normal limits. This allowed the fibre-optic link to be ruled out as the source of the fault.
Cause identified, sector back in service
The fault was ultimately traced to a component in the affected equipment: the SFP module in the remote radio unit. Once the module had been replaced, the alarm cleared and the affected sector returned to full operation.
The assignment in Meißen illustrates what effective fault resolution at mobile network sites requires: technical understanding, structured troubleshooting, field experience and safe working practices, even under demanding conditions.
Assignments like this are part of our team’s everyday work. They demonstrate the variety involved in working on modern communications infrastructure – from testing in the equipment room to resolving faults high above the ground.