I meant bottom of my boots - i.e. my gear. When the "fifty" is called doesn't that mean my gear is 50 ft off the ground? Me sitting 15 ft higher is then 65ish ft up in the air.
I am not saying I have the answer - but I think the radio altimeter is calibrated to read distance between the wheels and the ground. Thus I am not going to drag my wheels through the approach light for being "a tad low on my RA",