How can one satellite dish feed 100 receivers?

DIRECTV’s dishes are the same whether you’re feeding a home or a high-rise. One dish like the one you see here can serve hundreds of apartments or hotel rooms, even though there are only four wires that come out of it. It may seem like magic but it’s simple science.

There are two bits of technology that make this all possible. DIRECTV has over a dozen satellites but your dish doesn’t really know that. It’s looking for signals based on where they are in space and the frequencies they occupy. There’s also a third criterion called “polarity” which (to make this really simple) explains how the signals “look” in 3 dimensions. A radio signal is really a sine wave but it can be “polarized” so it only works when looked at a certain way.

When a satellite dish receives signals, it breaks them up into one of four categories, each corresponding to a different set of satellite signals in the sky. Two different voltages are assigned and two of the signals have a 22kHz “tone” added to them, so there are four possible choices. Most national HD signals are shifted to a low frequency (the so-called “B” Band) while SD signals and a few HD ones are shifted to a higher frequency (the so-called “L” Band.) Since every one of your channels belongs to one of those four categories, only four wires are needed to serve every receiver.

In an old-school setup, the receiver has a lookup table, finds out which type of signal is needed and asks for only that signal. In a modern setup the request is made to the SWM multiswitch which is always receiving all four signals all the time.

That’s the other part of the puzzle. You can split those four satellite lines from the dish as many times as you need (adding amplifiers along the way) but you still have four lines. Plain splitters aren’t going to let you connect to hundreds of receivers but a multiswitch will. A multiswitch, like the one above, connects to all four lines all the time. It takes a request from a receiver for one of the four signals and sends it down the wire. A multiswitch like the one above can feed up to 32 receivers and can feed another multiswitch for 32 more. If you split a satellite line 8 ways (which is quite possible if you’re using multiswitches) that means 512 receivers.

These basic concepts are the core of DIRECTV’s apartment and hotel systems, and that’s what sets DIRECTV so far apart from other systems like traditional cable TV which require expensive headend distribution. It’s what makes DIRECTV a winner!