Cheap “spy bug” detectors are not good for much other than giving a false sense of security, a MyBroadband test of the K–68 Anti-Spy RF Detector has found.
MyBroadband recently came across an inexpensive bug sweeping device for around R1,500, which claims to be able to detect spy devices such as wireless cameras and the like in your home.
We could not resist buying one and putting it to the test.
The K–68 Anti-Spy radio-frequency (RF) detector has 3 different operating modes to detect unwanted devices.
Its main mode detects RF signals and should help you narrow down where a signal is coming from to locate a specific device that may be spying on you. This is the main feature of the device.
It also has a magnetic detection mode and an infrared mode marketed as an easy way to spot cameras.
We compared our bug sweeper with an RS Pro IM–195 RF field strength detector to verify that the RF detection mode is working, using a Wi-Fi router and 2.4GHz RC transmitter as sources.
As expected, the reading on the Bug detector did increase similarly to the reading on the RF field strength detector and had a loud alarm going off when it got close.
The bug detector claims to be sensitive to frequencies up to 6.5GHz, so the next test was with a 5.8GHz analogue wireless camera.
These are readily available and could transmit video from outside a building, and are also commonly used on consumer drones.
While the detector did manage to pick up a difference in field strength very close to the transmitter, it was much more sensitive to the 2.4GHz Wi-Fi signals.
When set sensitive enough to pick up the video transmitter, the alarm would already go off due to Wi-Fi devices in the same room.
The camera detection mode shines some red and infrared lights out of the back of the device and has a little window that filters out most other light.
This should allow you to see reflections from a camera lens very easily, but in reality, any somewhat reflective surface looks the same as a camera lens.
So it is not really any more useful than just looking for cameras with your own eyes.
The magnetic detector seems to use a basic magnetic switch on an extended rigid wire, which allows you to get in behind objects to look for magnets.
Unfortunately, it has to get very close to a magnet to detect it. So without going over every square centimetre of your house, it will likely miss devices attached with magnets.
Finally, we planted some hidden video transmitters and cameras in a room and tried using the bug sweeper to find them.
For this, we mainly used the K–68’s radio-frequency signal detection.
The sensitivity was adjusted so that the bug sweeper just barely picked up a signal and then pointed in various directions to see where the signal was the strongest.
We then moved in that direction, turned down the sensitivity a little, and repeated the process.
In the first attempt, this test led us to a nearby TV box connected to the Wi-Fi network.
When the TV box was disconnected, the next device to be found was the main alarm controller for the house, which has both Wi-Fi and other proprietary wireless connections.
After this too was powered down, we could still not find the hidden video transmitters and cameras. The bug sweeper gave random alarms when set to any sensitivity above the noise floor and in no particular direction.
While our budget bug detector detects some wireless signals and allows you to trace them to their source, it is not practical in the modern world with connected devices and Wi-Fi signals all around you.
Without being able to differentiate between radio-frequency bands and signals like a true spectrum analyser, the usefulness of the bug sweeper was limited.
In the end, it could not detect the signals coming from hidden spy cameras over the rest of the RF noise in the room.