Just a question. Do all jammers emit visible light when activated? I was watching a video today on a jammer don't recall which but I did notice when the jammer was activated I saw blinking of the heads and just wondered if they all do this when they jam. In a night time activation is this apparent and if so at what distance can this be detected? I thought the 904 beam was near infrared and wasn't visual but in the videos the jammers looked like weak strobes firing.