Most transmitters in the 2.4 and 5 GHz bands make a unique shape, or "signature". Since they all look a little bit different, we can use these signatures to identify what kind of device is transmitting, which makes tracking things down a lot easier.
If you are having trouble identifying a transmitter's signature, look through these examples to try to figure out what it is.
Bluetooth devices are active in the 2.4 GHz band. These devices are frequency hoppers that impact all channels, so you can't move your WiFi to avoid their transmissions. However, Bluetooth devices are relatively low-powered and hop very quickly, and will have limited impact on WiFi devices. It isn't until many Bluetooth devices are active simultaneously that you are likely to see problems with your WiFi.
Not all cordless phones create the same pattern in the spectrum. Some may create a constant spike in amplitude, while others may frequency hop across the entire spectrum. Cordless phones may change their frequency each time they are used. Channel changes will be noticeable in the amplitude history or waterfall.
Microwave ovens operate in the 2.4 GHz band, and typically create a mountain-like shape in the Density View. Most people use a microwave oven in exact time lengths like 1 minute bursts, which are easily measured in the Waterfall View. The amplitude levels of microwave oven leakage in the 2.4 GHz vary depending on their age, shielding, and distance from the spectrum analyzer.