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How Do I...Connect Multiple DSS Receivers - HomeTechDon't you hate it when everyone tells you that something is possible, but nobody can tell you exactly how to do it? Well, this page describes one the great mysteries of life: How to connect a DSS antenna to multiple DSS receivers. Plus, it describes how to run both DSS signals and antenna or cable signals down a single coax!If you have been researching DSS, you've probably run into terms such as Dual LNB, Multiswitch, and Diplexer in reference to connecting DSS to multiple satellite receivers. We did a lot of research and still didn't really understand how it all worked. It wasn't until we just went out an bought all these things and actually installed a relatively complex system (in one of our own homes), that we finally "got it". There are several ways that you can view DSS programs on multiple TVs. We start out describing the minimum wiring you'll need in your walls, and then we go through some sample distribution systems, by increasing levels of cost and features. |
Frequently Asked Questions about DSS WiringWhy can't I run multiple receivers off of one coax line from my dish?
How Dual LNB and Dual Satellite Systems WorkThe most important thing to understand about DSS systems is that the receiver box actually tells the antenna (dish) which channels it wants. The active part of an satellite antenna is called the LNB. In high-power DBS (Direct Broadcast Satellite) systems such as DirecTV and Dish Network, each channel is broadcast from the satellite with either a "left hand" or "right hand" circular polarization.An LNB can only receive one type of polarization at a time.Roughly half of the channels are one one polarization and half are on the other. The satellite receiver has a table (downloaded from the satellite) of which channels are on which polarization, so it "tells" the dish which polarization to select and deliver down the coax. It does this by placing a variable voltage on the cable. (See table below.)
So lets say that you have a single LNB dish that you have split with the appropriate high-frequency splitter and ran to two satellite receiver boxes. |
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Prewiring for DSSThe current standard for wiring a full-featured video distribution system is pulling two dual- or quad-shield RG6 coaxial cables from the headend to each outlet. (One for signals coming down and one for signals going back to the headend.) Until recently, we've been advising customers that want DSS to run an extra coax to the locations where a DSS receiver will be located. Well, better safe than sorry. It didn't hurt anything and, although we hadheardthat there was "stuff" available that made that unnecessary, we had not actually seen it work ourselves. With the advent of "dual tuner" devices such as DirecTIVO and Ultimate-TV, we are now advising pulling at least three coax cables to any location that may have one of these new devices.I turns out that the rumors were true. Youcanrun both DSS signals and conventional VHF/UHF or CATV signals down the same piece of coax. So now we are advising our customers as follows:
The only hard part is locating the actual DSS satellite in relation to your location so that you'll know where you can mount the dish. Out here in northern California, it's southeast of us and about 40 degrees up in the sky. The satellite is actually located directly south of Texas, above the equator. Use the map to determine the approximate azimuth (compass reading) and elevation of the satellite. For instance, in Los Angeles California, their DSS dishes point at 135 degrees and up 45 degrees. Single DSS Receiver, Modulated For Other TVs The simplest (and least expensive) way to hook up DSS so that any TV can watch is shown in the figure to the right. With this setup, you can watch any antenna or cable station at any TV, and any TV can watch whatever is currently selected by the DSS receiver. Note that everyone will have to watch the same DSS program! Since there is only one receiver, there can only be one DSS program shown on the "in-house system" at a time.
A dual-LNB dish (or it could be a single in this case) feeds a diplexerturned backwards to merge the satellite signal with the antenna or cable signal onto a single cable. (Just be sure to connect the cables to the proper jacks on the diplexer.) At the outlet, another diplexer splits the satellite and antenna signals back out for the satellite receiver and TV to view. Video and audio cables connect from the satellite receiver to a modulatorwhere it is converted to an unused channel. The modulated signal is sent "upstream" to the headend where a combiner (a splitter turned backwards) joins the antenna/cable signals with the new channel. This combined signal is then split as many times as you have TV locations, including the location with the satellite receiver. Note that you will probably need a little amplification of the non-satellite signal between the combiner and the splitter. And you may need amplification of the satellite signalbefore the first diplexer. Two DSS Receivers, Each Modulated For Other TVs The next step up is to use two receivers on a dual-LNB dish with modulators on each receiver. Now, there are two locations where you have all TV channels plus DSS. And the rest of the TVs can watch any channel, or either of the DSS receivers. Note that this arrangement is simply an extension of the previously described hookup.
Note that adding a second receiver does not double your monthly DSS bill; they have special rates for additional receivers that are quite low. The way they keep you from cheating is that all receivers must dial out from the same phone number! Although the drawing at right looks complicated, it really isn't that bad. Notice how all the "differences" from the simple version to this version and beyond occur at the headend and just the TV locations where a satellite receiver is added. The service entry of the satellite signals and antenna or cable remain the same. As does all the wiring in the walls, and all the TV locations where there is not a DSS receiver. Three to four DSS Receivers, No Modulation This figure shows how you can break the "two receiver" barrier using a
multiswitch. The multiswitch takes both cables from the dish and "shares" them with multiple recievers. It also takes in an antenna or CATV signal and, using built-in diplexers, combines it onto each of the outputs. Each output must run directly to one, and only one, satellite receiver. (But it's ok if there isn't a receiver installed on every cable.)
At the other end, if you do have a DSS receiver, you split the DSS and VHF/UHF signals with a diplexer. We sell multiswitchs four or eight outputs. If you have more than eight TV jacks, but only eight or less will have satellite receivers, you can split the VHF/UHF signal just after the combiner and run this signal to the other TV jacks. When using a multiswitch, you can count on needing a regular VHF/UHF/CATV amplifier between the combiner and the multiswitch. The multiswitches we carry amplify the satellite signal, but not the VHF/UHF/CATV signal. Five to eight DSS Receivers, No Modulation To support more DSS receivers, you can use more than one multiswitch. Each multiswitch will have to get feeds from both LMBs so each coax from the dish will have to have a
DSS Signal Amplifierand KU band splitter.
Be sure and connect each feed from the dish to the same port on each multiswitch or they won't work right. SummaryWell, that's about it. These drawings and explanations should give you enough to go on to configure your system. The VHF/UHF/CATV side of things can be as simple or elaborate as you want, but the DSS side must follow one of the layouts described here. Keep in mind that everything you know about VHF/UHF/CATV video distribution just doesn't apply to DSS configurations. Happy viewing! |
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