Hello, It looks like I'll have to do the T/R mod for my 2012 KPA500 :-( The vy good instruction https://ok1rp.blogspot.com/2017/02/elecraft-kpa500-lpf-tr-switch-rework.html recommends for Q5 -> BU941T, but it is no longer available from any of the major distributors. Is there a replacement model? 73 Tom DK3DUA