How to Locate Interference with Device Finder

Device Finder is a feature in Chanalyzer that you can use to physically locate narrowband transmitters.

The Device Finder view shows a signal strength over time graph similar to the Networks Graph, but also shows the signal strength of a selected frequency range. Device Finder will enable you to actively seek out transmitters so you can know exactly what is happening around your network.

What Types of Devices can Device Finder locate?

Narrowband transmitters are devices that create a constant signature in the spectrum that is less than about 10 MHz wide with a strong amplitude. Cordless phones, baby monitors, wireless audio systems, and wireless video cameras typically create narrowband signatures in the spectrum. These devices can be located with Device Finder.

Direct Sequence transmitters make generally curved shape in the spectrum with low amplitude. Since they can cover 20 MHz of spectrum or more, and since the amplitude is usually lower, Device Finder doesn't locate them as easily.

Frequency-hopping transmitters move from channel to channel. Xbox 360 controllers, Bluetooth devices, and most video baby monitors are frequency-hopping. Because they move around, they can't be tracked by Device Finder.

Attaching the Device Finder Antenna

To attach the Device Finder:

1. Unscrew the omni-directional antenna from the antenna connector on the Wi-Spy

2. Screw the device Device Finder to the antenna connector on the Wi-Spy

Note: Since Wi-Spy is receive-only, it's completely safe to switch out the omni-directional antenna for the Device Finder Antenna while the Wi-Spy is active.

How to Use Device Finder

1. Click and drag in the Density view to select the signature of the device that you want to find. Release the mouse button, and select Device Finder.

2. Optional: clean up your selection with the Selection Handles.

3. Click the Checkbox button to begin Device Finder Mode. Chanalyzer will now open the Device Finder view.

4. The Device Finder tab shows the amplitude (signal strength) over time for the area that is selected in the Density View.

5. As you move around, the Amplitude Graph will rise and fall.

• If the signal strength graph moves up, you are moving in the right direction
• If the signal strength graph moves down, you are moving in the wrong direction

6. The Stacked Bar Graph on the right also visualize amplitude trends

• Blue shows the current amplitude (signal strength) of the device
• Red shows the peak amplitude of the device (the more red, the worse)

7. When you locate the offending device and unplug it, the amplitude graph will fall to nearly "zero".

8. Click the X in the upper right to close Device Finder mode.