The frequency of a digital data signal, such as a digital video signal, is intentionally varied or hopped before being sent over a network. This frequency hopping may be performed in accordance with a frequency hopping pattern shared with only intended receivers. The digital data signal may be further intentionally pre-distorted in accordance with a pre-distortion pattern which is also shared with only intended receivers. The frequency hopping and/or the pre-distortion patterns may be used to vary the frequency and modulation, respectively, on a periodic basis, such as a symbol-by-symbol or packet-by-packet basis.