Here is my FT 817 ready to Fit the Filter
With the cover carefully removed - locate the mounting point at the front The Filter sits with the 3 lugs to the left/4 lugs to the right
Filter mounted onto main board ___________________________________________________
Now all that is required is to go into the main menu to #38 where it should say OP FILTER and just above it should read the word OFF, rotate the main dial to read CW. Press the Function button to exit the menu - then quickly press it again to go into the quick functions and rotate the knob until you reach IPO ATT NAR push the NAR button to engage it and it should now switch into cw narrowif it isn't already - if you want to switch between the two press NAR again - All straight forward, and I have to say what difference. I hope this sequence is of use to anyone contemplating this Filter.