Q: I use a three-year-old Chromebook on a secure home Wi-Fi network. Recently, the Chromebook has been getting disconnected from the internet every day about 4:45 p.m. After I unplug and plug in the router, the internet works again. This doesn't happen with either my laptop or tablet computer. What's wrong?

Ken Burrows, Colorado Springs

A: Given the clocklike precision of your Wi-Fi outage, I think it's caused by outside electronic interference from another Wi-Fi network, a gadget or a home appliance that turns on at a specific time every day — either inside your house or at a neighbor's.

Why would interference affect only your Chromebook? Perhaps the interference occurs in only one part of your house. Or maybe you haven't used your other devices at 4:45 p.m.

Here are some common causes of Wi-Fi interference:

• Neighboring Wi-Fi networks that overlap with yours.

• Microwave ovens, fluorescent lights, garage door openers, cordless phones and baby monitors.

• Bluetooth electronic devices such as wireless speakers, keyboards, mice and key-finders.

• Motion detectors that use radio waves or microwaves, and wireless security cameras.

Regardless of the source of the interference, you can try to fix the problem by moving your wireless router within your house, or not using too many wireless devices near each other.

Or, if you have a router that uses only the 2.4 gigahertz radio frequency, you can buy a dual-band router that uses both the 2.4 gigahertz and 5 gigahertz frequencies. The 5 gigahertz frequency travels shorter distances, and is less likely to pick up interference from a neighbor's Wi-Fi.

Q: I rent a combination cable modem and Wi-Fi router from the Comcast Xfinity internet service for $14 a month. I'd rather buy a replacement modem than continue to rent one. How can I find a compatible replacement?

James Martin, Maple Grove

A: You have two choices. Buy a Comcast-compatible cable modem that has a built-in wireless router ($90 to $350), or buy two devices, a compatible stand-alone cable modem ($50 to $230) and a stand-alone router ($30 to $240.)

To find cable modems with and without Wi-Fi, read Comcast's "approved modem list" (see tinyurl.com/y2zlt8rv) or go to the websites of electronics retailers such as Micro Center or Best Buy and search for "Xfinity cable modem." Read the product details to find out if a particular modem includes Wi-Fi capability.

If you buy a modem and a router separately, only the modem needs to be Xfinity-compatible.

Two readers, Barbara Meyer of Maple Grove and David Raymond of Minneapolis, responded to a question from Lori Larson of St. Paul, whose Android phone had trouble connecting to her new Hyundai car via the Android Auto software (see tinyurl.com/y628gq2c).

Both said they'd solved similar problems by getting new Android phone cables to connect to their cars. Unfortunately, that's not the solution for everybody. Larson had also replaced her phone cable, but it didn't help. I still think Larson's problem was the age difference between her car's new software and her phone's aging Android 8 operating system.

E-mail tech questions to steve.j.alexander@gmail.com or write to Tech Q&A, 650 3rd Av. S., Suite 1300, ­Minneapolis, MN 55488. Include name, city and telephone number.