Criminal’s using Jamming Devices

The jammer would only have to put out a little more than the device being jammed, if it's in reasonable proximity. The receiver is going to look at the strongest signal. The jamming signal would have to be somewhat broadbanded to cover the various frequencies within the 2.4 gHz band.

The link said it jammed police radios too. Usually those are 2m or 440mhz. That would be broadband for sure.