There are two main classes of electronic devices: 1. Devices that are unintentional radiators 2. Devices that are intentional radiators The concern is that pe

There are two main classes of electronic devices: 1. Devices that are unintentional radiators 2. Devices that are intentional radiators The concern is that people may not know which class their device falls into, and also that they may not know how to fully disable their device as well. The problem with intentional radiators is more obvious - it could potentially jam other circuits by producing energy at specific frequencies. However, many people seem to ignore the other class of unintentional radiators. Many circuits require the use of clock generators and phase-locked loops, which can actually radiate a fair distance away if not designed correctly. One of the problems with this is that noise generated by a PLL could intermodulate with the PLLs in the plane's navigation systems (i.e. GPS or ADF) and cause the pilot to use an inaccurate position report in determining the location of the plane. An example of one such interference case: Someone wanted to launch a high-altitude balloon with onboard GPS and an amateur radio transmitter. They added a small keychain camera manufactured by a Chinese company, but when the camera was powered on, it completely disabled the GPS from locking on to any satellites.