USB Gadgets and Crowded 2.4GHz Band Can Slow Wi-Fi as Wi-Fi Calling Shows Limits

In one report, Engadget said many wireless devices use 2.4GHz, a free-for-all radio space designated in the mid-1980s that microwave ovens also use. Because the frequency is cheaper and easier for manufacturers to build into devices, it has become crowded. Neighboring offices and apartments add to the load, and signals push against each other. Unless a network uses only 5GHz or 6GHz, as with Wi-Fi 6E and 7, the congestion likely affects Wi-Fi speeds. The newer bands are faster and less crowded but have limited range and distance, which is why Wi-Fi 7 networks can sometimes feel slower when signals struggle through walls and devices default to 2.4GHz.

The 2.4GHz band is divided into channels, usually 1 through 11, with some channels left free to reduce friction, Engadget said. Even so, dozens of devices on those channels can weigh on the radio signal. USB 3.0 adds another problem: high-speed data on USB 3.0 creates electromagnetic radiation spanning 2.4GHz to 2.5GHz, which can interfere with wireless networks in those bands. One solution is to use USB extension cables to move USB dongles farther from ports, reducing overall noise. Bad router placement, overlapping Wi-Fi channels, especially in urban areas, and large uploads or downloads also contribute to poor network experiences.

Engadget's advice is to prioritize devices. Users can consider which connected dongles and devices they can live without most of the time, whether basic peripherals can connect using USB 2.0, and whether devices can be moved farther apart with USB hubs or extension cables. Cordless phones and microwave ovens should not sit right beside the router. The goal is to prune the devices crowding the network and create physical space between them, giving radio waves more room. Before diving into router settings, Engadget recommends rebooting the router, which clears its cache and forces it to choose the least noisy channel.

In a separate report, Engadget said Wi-Fi calling, also called VoWiFi, can improve sound quality on Android phones and iPhones. When enabled, it runs calls and texts over a Wi-Fi connection instead of the carrier's cellular network. It routes the connection through an IPsec tunnel and an ePDG connection, similar to a VPN, to the carrier's network. From there, data is sent to the other device as usual, so both devices do not need Wi-Fi calling enabled for the feature to work.

Wi-Fi calling can allow calls and texts in areas with little or no cellular coverage. Engadget said dead zones in homes or offices can come from building materials rather than carrier faults. Certain window types, metallic coatings, metal beams, masonry walls, and thick concrete can weaken signal strength. Wi-Fi calling can also offer better call quality because it avoids cellular obstructions, tower congestion, and fluctuating signals. On a strong connection, it can enable HD voice. The feature is also designed to be seamless: users turn it on, do not need separate apps, and their contacts do not need the feature. Most carriers do not charge extra or count it against a plan, and calls should switch to cellular if Wi-Fi cuts out.

Those benefits depend on the Wi-Fi network. Engadget said poor or congested Wi-Fi can cause choppy audio, lag, or dropped calls, and the seamless handover to cellular is not always guaranteed. T-Mobile requires a minimum of 2Mbps upload and download speeds for Wi-Fi calling, the report said, while other major carriers do not explicitly state minimum requirements but are likely similar. T-Mobile specifically does not support Wi-Fi calling over satellite internet or a phone hotspot. For handovers to work, VoLTE must be enabled because 2G and 3G networks cannot handle them. Even then, handovers can be bumpy.

Emergency calls are an exception. Carriers only route 911 calls over Wi-Fi when there is no cellular network, so if the Wi-Fi signal cuts, there is nothing to hand the call to, according to Engadget. Wi-Fi calling works on private and public networks, but it is not risk-free. Carriers use an encrypted tunnel between the phone and their network, though protection depends on the phone's chipmaker and carrier implementing it properly. A 2024 CISPA study found vulnerabilities that put the Wi-Fi calls of around 140 million customers in different countries at risk. The flaws have been patched, Engadget said, and keeping devices updated is the best way to secure calls. Not every carrier supports the feature, and setup often asks for an emergency address because Wi-Fi calls do not go through a cell tower.