When selecting a CW transmitting frequency, what minimum frequency separation from a contact in progress should you allow to minimize interference?

Continuous Wave (CW) or Morse code signals use a very narrow bandwidth, typically around 150 Hz. Therefore, to avoid interfering with an ongoing CW contact, a minimum frequency separation of 150 Hz to 500 Hz is generally sufficient. This is vastly different from voice modes like Single Sideband (SSB), which require a much wider bandwidth of 2 to 3 kHz. Because CW takes up so little space on the band, many stations can operate very close to one another without overlap. Leaving a gap of 150 to 500 Hz ensures that your signal falls completely outside the narrow audio filters used by the receiving station.