Drake watt meter going below 0
 

Yesterday I was playing around with a new power supply and using an Icom 706
just to provide a load for it. From the Icon I went to a Drake W4 meter and
then to a 200 watt dummy load. The dummy load has a very low SWR by sevearl
metes. Almost no reflected power.

When I put about 100 watts into the system I noticed the W-4 meter
deflecting to the left in the reverse mode and about 100 watts in the
forward mode.

I have seen and understand several other oddities such as more power
reflected than going out and SWR showing up differaent at different power
levels. This is the first time I have noticed a meter going bleow 0.

Has anyone seen this and have an explination for it ?