Editing Diplexer (section)

==Residential==
Diplexers are also used in the home to allow a [[direct broadcast satellite|direct broadcast]] [[Satellite television|satellite TV]]  [[satellite dish|dish antenna]] and a [[terrestrial TV]] antenna (local broadcast channels) to share one [[coaxial cable]].  The dish antenna occupies the high frequencies (typically 950 to 1450&nbsp;MHz), and the TV antenna uses lower [[television channel frequencies]] (typically 50 to 870&nbsp;MHz).  In addition, the satellite also gets a DC to low frequency band to power the dish's [[block converter]] and select the dish antenna polarization (e.g., voltage signaling or [[DiSEqC]]).  The diplexer is useful in homes that are already wired with one cable, because it eliminates the need to install a second cable.  For the diplexer to work, the existing cable must be able to pass the satellite frequencies with little loss.  Older TV installations may use a solid dielectric [[RG-59]] cable, and that cable may be inadequate.<ref>Legacy satellite receivers instructed the LNB to send only one polarization (half the possible channels). Modern receivers have dual channels, so they may need both polarizations at the same time. A DishPro LNB "stacks" the two polarizations (sends both polarizations down the same cable; one polarization is sent in a higher (stacked) band). Consequently, the LNB signal occupies a wider bandwidth, 950 to 2150&nbsp;MHz. RG-59 has significant loss at the higher frequencies.</ref> [[RG-6]] cable is typically used for satellite feed lines.

In this application, there would be a diplexer on the roof that joins the satellite dish feed and the TV antenna together into a single coaxial cable.  That cable would then run from the roof into the house. At a convenient point, a second diplexer would split the two signals apart; one signal would go to the TV set and the other to the [[Integrated receiver/decoder|IRD]] of the DBS [[set-top box]]. These usually have an antenna input and a diplexer, so that the antenna signal is also distributed along with the satellite.

More modern installations confront several issues. There are often multiple satellite dishes that need to feed several receivers or even multichannel receivers. See, for example, [[single cable distribution]].

Diplexers were also used to combine UHF TV and VHF TV and FM signals onto one downlead, which can then be split back into its component parts as required.