Harris County officials detail communications impacts of unprecedented flooding in aftermath of Hurricane Harvey

Lin said the Harris County LTE network—the first operational 700 MHz Band 14 public-safety LTE system in the U.S.—encountered more outages , although 90% of the sites remained operational throughout the event.

“We lost four sites, and we were able to bring two back,” Lin said. “With the other two, we’re still evaluating them, but they just had so much water in them—one of them had 49 inches of water in it—that we’re still trying to evaluate the extent of the damage in those two sites.”

Lin said the eNodeB components at the LTE sites have proven to be quite resilient.

“We think some of these sites withstood having a couple of feet of water inside the shelter,” he said.

In terms of backhaul, McMillan said that Harris County encountered “a couple of issues” with sites served by copper wires, but all fiber backhaul paths have maintain functionality, as long as the electronics at either end were not under water.

“We had that happen at probably at least five LTE sites—where we lost the redundant link—because the fiber carrier’s junction box got flooded,” McMillan said.

“We have microwave redundancy at most of the sites. So, where we lost primary fiber, the network automatically went to the microwave [backhaul].”

McMillan said the Harris County LTE system was used to support public-safety communications in area command vehicles and a remote 911 center.

McMillan said the county was able to maintain power at all LMR and LTE sites, although it was challenging to do so in certain situations.

“For the most part, we didn’t lose power,” he said. “Where we did lose power, we just had to get fuel to it. Because the areas were flooded, it was tough to get fuel to the generators, so we had to get high-water assets … to help escort fuel trucks into flooded areas to fuel stuff.”

Harris County did not have any towers on the LMR or LTE networks fail. Most of the Harris County LTE sites are built to meet the TIA 222 Revision G standard—commonly referenced as “Rev G” within the industry—for structural design and fabrication, so the Harvey winds in Harris County were not an issue, Lin said.

 “This is a water event for us and not a wind event,” Lin said. “If we get hit by 170 miles-per-hour winds, I don’t know the answer to the question [about whether towers would remain intact] right now.”

McMillan said that the Corpus Christi LMR system—located near the area where Hurricane Harvey made landfall—lost an LMR site to wind damage and predicted that communications networks affected by Hurricane Irma could be tested similarly.

“In Florida, I think you’re going to see a separate problem, because of the wind,” McMillan said.