Atomic clocks in the US set themselves by picking up a radio signal out of Colorado. For best results select a location where it will be at least six feet away from a TV, computer, air-conditioner or other household electrical appliances. It is best near a window. Windows facing Colorado provide the best access to the signal.
Other sources of interference to be aware of:
- Large buildings
- Metal roofed buildings
- Buildings or rooms full of electrical and/or radio equipment