Hi mike:
I normally stay out of the tall grass, but if I must, I sometimes switch to my 4" coil...It is SLOW going, but it cuts through the grass and weeds better...The VLF machines are notorious for falsing when bumped against a hard object....Just have to live with it....I turn my SENS down to about 10 o'clock when in the tall stuff...loose a little depth (about 1-1 1/2"), but makes life a little better...I sometimes will stomp down an area, then detect it....Best bet, is like nugget suggested...get the owner to mow it, or get permission to weed wack it or something (those hand held metal dual-edged weed wackers you swing back and forth)...
HH
BH-LandStar