I have a Silicon Dust HDHomeRun dual QAM/ATSC tuner feeding a Mac Mini that is hooked up to a HDTV. The same cable feed is used for a cable modem and a direct connection to the HDTV. A passive 4-way splitter was doing the job for over a year, but the HDTV and internet performance was slowly declining. The cable guy replaced the drop cable to house, but unfortunately, the signal strength did not improve significantly. The signal going into the house was +10.5 dBmv (typical expected value), but after a fifty foot run and a final 4-way split, the signal was -8 dBmv at the cable modem (the signal typically varied between -9 and -7 dBmv). The HDHomerun tuners were detecting a signal strength of about 80%, which is at the extreme low end of providing a reliable QAM signal. In fact, many recorded shows were less than perfect. After doing some additional research and reading the reviews of all the PCT amplifier products here at Amazon, I decidied to purchase the 2-port PCT amplifier.
My final setup is a passive two-way splitter where the cable enters the house followed by the PCT amp followed by a fifty foot run, and finally, the original passive 4-way splitter (2 HDHomeRun tuners, HDTV, and terminator on fourth output). As it turns out, the cable modem should either be dirctly connected to the cable (impossible if you have a TV) or at the MOST, after a 2-way split. The outgoing (upstream signal) is often overlooked. Thus, the cable modem has a separate feed from the initial passive 2-way splitter. The upstream cable modem signal went from 53 dBmv to 48 dBmv (below 50 dBmv is great) and the downstream signal varies between -2 and 0 dBmv (-5 to +5 is ideal; note that the cable modem was NOT amplified). The HDTV has been spectacular! Both signal strength and signal quality register well above 95%, more often at 100%. And the bonus is that I have an unused amplified output, that currently has a terminator, that will eventually be used for future expansion of coaxial outlets in other rooms.
The no-brainer is to purchase an inexpensive PCT amp, but do your research on how much ampification is required and if necessary, how to deal with signals for both a cable modem and HDTVs. An excellent source is the supplier of the amps at CableTVamps.com.
Thanks to everyone who posted the previous reviews of PCT amps and inspired me so solve my cable problem.