...The HM-102 does have a sensitivity knob on it, on the front that is helpful when trying to use the tuner for bands that are far off, you can turn the sensitivity down and find that you are coming down in SWR, until you dial it in. At full scale it matches the SWR meter in the rig. I just don't understand why at higher power it's SWR rises, but the rig does not...
The SWR meter in the rig is designed to be independent of output power: it contains a circuit that
compares the forward and reflected power and calculates the SWR from that.
The HM-102 gives an indication of forward and reflected power, rather than SWR. You have to
set the sensitivity control so it reads full scale on forward power, then switch to reflected power
in order for the SWR readings to be accurate.
When you change output power, the meter in your rig automatically compensates because the
ratio between forward and reflected stays constant for a given SWR. But the HM-102 just
shows you the relative reflected power on the SWR scale. As your output power increases,
the reflected power increases. That makes the SWR reading higher. But if you readjust
the sensitivity control so the meter is full scale in the forward position again, the SWR
readings should still be good.
So each time you change output power level, you have to readjust the sensitivity control
on the HM-102 to full scale in the forward position, then the SWR readings will be accurate.
If you don't, they won't be.