I have a "decade box" of sorts to use when I attempt calibration, should I actually do it. We have a club event coming up on the 21st of April that I can compare it to better quality analyzers at the location we are doing the event. There are 8-10 antennas on site, so I can compare the MR100 back to back with another analyzer on the same antenna. If it looks similar, I won't calibrate it.