Whoever was saying 'check, check, check' for the better part of two hours on 123.45 in the NorCal area Thursday morning. Two aircraft were using that freq to do some air-air coordination for some testing. One aircraft would say 'one-minute out', then about the 1 minute mark, this dude would start saying 'check, check, check' obnoxiously for about 30 seconds in what seemed like an effort to mess up the aircraft doing the testing.