Several Minneapolis readers have reported uneven city Wi-Fi service quality, and they wondered whether the leaves on the trees are blocking the signals more than expected.

The answer is yes. The re-emergence of leaves this spring has caused network delays and slower-than-expected download speeds in parts of the citywide network. But the problem is being fixed with antenna adjustments that should be completed by mid-June, said US Internet, the Minnetonka firm that built and is operating the Wi-Fi network.

The scope of the leaf problem is small, affecting 163 antennas out of 3,000 in the city, said Joe Caldwell, marketing vice president of US Internet. The problem is twofold: Leaves might block a homeowner from receiving a signal from a US Internet Wi-Fi antenna, or they might obscure the view between two antennas, which disrupts the network's radio relay system.

The leaf problem is unrelated to the much-discussed Wi-Fi "black hole" areas -- particularly around Lake of the Isles, Lowry Hill and Loring Park -- where existing light poles can't support Wi-Fi antennas and new poles must be installed. Those areas should get service by the end of September, city officials say.

To solve the leaf problem, US Internet is adjusting the height of antennas on city light poles in order to transmit signals under or above the leaves, Caldwell said. In other cases, the firm is adding relay antennas to reroute signals around trees.

Some readers asked why leaves still are a problem, since that issue supposedly was resolved last summer by adding more Wi-Fi antennas citywide.

Construction delays caused much of the Minneapolis Wi-Fi network to be built over the winter, when potential leaf interference could not be taken into account, Caldwell said.

"The stuff we're fixing was installed during the winter months," Caldwell said. "We'll only have the leaf problem this year."

Lynn Willenbring, chief information officer for the city of Minneapolis, agreed that the leaf problem is "very addressable."

The city is not paying for the network, but it will be an anchor tenant on it and also will decide this month whether the network meets the performance levels agreed to in the city's contract with US Internet. The city expects to approve the network, Willenbring said.

The city is shifting some inspection and construction workers and some city facilities to the Wi-Fi network from cell phone or land-line data connections, Willenbring said. The city police and fire departments are testing the network, but they won't use it until the "black hole" areas have service, she said.

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