Standard configuration is a Mast-Mounted Preamp with DC Voltage supplied
via the Coax from a Power Insertion Module, usually located behind the TV.
The PIM is designed so that it does NOT supply DC Voltage to the TV, so
no special protective devices are required:http://winegard.com/kbase/upload/2451964.pdf
If the Coax downlead goes through RF Splitter(s) to various TVs, PCs, etc,
then ONE location for the Power Insertion Module is between the
Preamp and the first Splitter, which sometimes means in the ATTIC.
DC Voltage ONLY goes up the coax to the Preamp, NOT to the Splitter(s).
PS: I have run across a few RF Splitters that had a DC Short on one or
more ports...which I quickly threw in the trash.
If you DON'T want to locate Power Insertion Module between Preamp and
the RF Splitter(s), then use SATELLITE
RF Splitter(s), most of which
have DC PASS on one or both ports. I doubt that there are very many TVs
with a DC Short on the coax input, but if there is, it's probably a stray wire
in one of the coax connections....and if not, a DC Isolator would fix it...http://www.solidsignal.com/pview.asp...u=615798102005
Alternative would be 3-Port SATELLITE RF Splitter pointed out by arxaw above...
If a VHF and a UHF Antenna go through a VHF/UHF Combiner (aka Diplexer)
prior to going through a Preamp, any of several devices listed next will work.
If the Preamp is only intended to amplifiy UHF signals (very common),
then DC PASS is needed on the UHF port, as provided by Radio Shack
15-2586 and Antennas Direct EU-385CF. Pico-Macom and Holland UVSJ
parts have DC PASS only on the VHF port (yes, very bizarre).