So this evening I'm hearing voice traffic on 4.025 MHz, on USB. I'm hearing numerous 3 character callsigns all starting with "8", such as "8KD", "8BS", "8AQ", "8AE" and "8JM". It appears to be some kind of traffic handling net (there is definitely a net control so it's some type of net). Numerous people are reading back messages to each other, one character at a time. Could this be MARS traffic? I've heard several references to message numbers. I'm guessing it must be MARS as I can't think of any type of other entity/group that would hold formal nets on HF outside the ham bands.