I have an old Drake 1KW LPF in line running 1500w output from an Alpha 87A to a TH7DX. It's worked fine for several years. I've pulled the LPF out of the line. At 28000 with 1500W out, the reflected power dropped from 200 to 100 watts. There is also an improvement on 20 and 15. Comments appreciated. 73, Steve WB6RSE