Karyn Wall has lived in Lemon Grove for the past 20 years, and to her knowledge, her home has never been targeted by criminals. However, she recently learned how vulnerable her home is to would-be burglars.

“My husband and I feel very secure, but I know we may need to do something about the house, the interior, the lighting, etc.,” Wall said.

Shanah Clevenger is a crime prevention specialist with the San Diego County Sheriff’s Department who runs the free Lemon Grove Home Security Consultation Program. She’ll consider anything that can be done to bolster home security, no matter the budget.

“Some of my suggestions are quick and easy and don’t cost a lot,” Clevenger said. “I just suggest: do what you can, or do it incrementally until you feel your home is secure.”

That security measure includes protection against a relatively unknown type of wifi jammer. NBC 7 Responds spoke to cybersecurity expert Jim Stickley about these devices, who said that even though they are illegal in the U.S., there are several websites where you can buy them and have them delivered to your door.

"I mean, you shouldn't panic," Stickley said. "It's real, but the number of criminals who actually use it is relatively small."

How do Wi-Fi jammers work?

Jammers disable Wi-Fi devices by overloading the Wi-Fi frequency, or any radio frequency, and large jammers have a fairly wide range of interference, Stickley said.

"It could take out a whole house, or even a couple of houses around me, and take out all the Wi-Fi," Stickley said.

Once the Wi-Fi is down, criminals can break in without the cameras capturing it.

How to disable a WiFi jammer?

Wired cameras won't be affected by signal jammer, of course. Remember: The memory chip will record video whether or not there's Wi-Fi. Plus, some security systems offer systems that send owners notifications when Wi-Fi is down.

"If you get a notification that the Wi-Fi can't communicate with the camera, you can say, 'OK, something might be wrong,' and then you can call a neighbor and say, 'Hey, can you go check it out for me?'" Stickley said.

Wall said she couldn’t imagine coming home one day to find her home ransacked by strangers.

“That would be horrible,” Wall said. “That would be horrible because you’d be worried if there was someone else in the house and wouldn’t want to go in. That would be a very scary situation.”

Wall hopes to continue living safely in Lemon Grove for another 20 years.

The sheriff’s department said technology is important to keep your family and home safe, but it’s just as important that you and your neighbors look out for each other. They can also help start a neighborhood watch program.