What exactly is the difference between a power inserter such as a PI-29 used to power a LNB and an amplifier such as a SA6AL? I read that some parameters used to measure amp. performance are power gain and efficiency. This seems to me to be characteristic of a power inserter. A power inserter locks lines to any of the 4 signals, 13V, 18V, 13V 22KHz, 18V 22KHz. I guess my question is what is the difference between the two devices since they both seem to increase power levels? I should know this but I dont; what is the relationship between power and voltage? Doesnt a greater amplitude imply greater power assuming the frequencies stay the same? Thanks.