You make an excellent point VOS. I do have decent head room already. According to tvfool, the NM values for the channels I receive range from 37 to 52 db. I lose part of that due to an attic install but of course add back the gain of the antenna. Conservatively speaking, let's say I lose 50% due to an attic install. My lowest channel drops from 37 to 18.5 db due to attic install but increases to 30.5 after adding back antenna gain. Assuming I lose 4 db per 100 ft of cable run and 3 db for each 2-way splitters, my distribution losses are only 13 db (4 db cable run and 9 db for 1 splitter and 2 AM21's). Perhaps, I'm good to go right now... However, I do want to build in some overhead due to lower signal with snow on the roof or leaves on the trees in the summer. A small distribution amp may be a wiser choice for me than a pre-amp.