When constructing shields, care must be taken to get the shield up to the connectors, since even a small length of uncovered wire will radiate effectively, particularly if the interference s RF is very high. Backshells are commonly found in aircraft wiring and may not be seen normally in TOCs. Other common RFI producers such as computer monitors require a more complicated wire screen shield. This gets difficult, since the screen must be very fine to allow the monitor to be viewed and yet also be an effective RFI reducer. An easy method of locating RFI in the TOC is to use a cheap amplitude-modulation transistor radio as a detection device.
Cheap radios have no filtering on the receiver so a broad band of energy is detected.
Simply by tuning between AM stations and then moving the radio near equipment, interference can be detected and heard as an increase in radio-noise level as the receiver approaches the source of interference. Some may argue that checking electrical bonding and tracking down sources of RFI is not the job of TOC Signal personnel. Obviously, once a source of interference is identified, it then needs to be suppressed. The ground rods themselves were always as long and as thick as practical, since physical contact between the surface area of the ground rod and the earth provided the low-impedance electrical path for both DC and RF currents to be dissipated into the soil. Connections to the ground rod were made with a heavy copper cable, copper strap or braided cable and wingnut fasteners.