Anything that emits at the same frequency range as GPR, from around 10MHz up to 6GHz, can be a potential source of noise for your data. Cell phone towers are a main source of interference. Collecting data close to cell phone towers will introduce significant noise levels into your data. Two-way radios, walkie-talkies and similar devices are also a source of interference. Also, the way an antenna is built and/or the method it uses to collect data can introduce noise into your data.