The fix is on in one of the menus in the Yaesu 847. After this mod the 847 will tune up to a 7:1 insted of 3:1
The first thing you need to do is get into the service menu. You do this by holding down the three buttons on the mic and turning on the radio.
The first menu will be Fm-51 do not change that one. Rotate the sub-tune knob until you see the menu that says SWR 3.0 to the left this you will see two small numbers or numbers letter combination. Rotate the MEM/VFO CH knob until you see 9A then push the menu button and you are done.