Ah, first world problems. What if your guest house were 700 feet from the main house? It’s a problem few of us have. Still, our phone reps talk to a lot of people and this question came up. One of our customers wanted to run a cable 700 feet from the multiswitch to the receiver. You can’t do it, and I thought the reasons might make a good article.
It’s all about loss.
As a signal travels through a cable, it loses some of its strength. The higher the frequency, the more it loses. Think of a signal traveling through a cable like you walking through a swimming pool. The further you go, the weaker you get. Eventually you can’t go any further.
DIRECTV SWM signals live up around the 1800MHz range. At that point, losses are pretty serious. Using typical RG6 cable, you would expect to lose about 42dB. That’s far beyond the range you can deal with.
Exiting from the multiswitch, the signal is about -25dBm. (If you don’t understand dBm, it’s ok, Just know that as the numbers get further from zero, the signal gets weaker.) The SWM signal should be stronger than -55dBm at the receiver or Genie client, so overall you can tolerate about 30dB of loss. By itself that would mean you could theoretically go 500 feet. Theoretically. There are a few problems with that theory, though.
You need to account for splitters.
A DIRECTV 8-way splitter will introduce 14dB of loss into the equation. Each connector introduces 1dB of loss. So if you’re going from the SWM, to a cable (2 connectors) to a splitter, to another cable (2 connectors) figure you’re at about 18dB of loss. So keep in mind the maximum amount of loss is 30dB, meaning you really have only 12dB to play with (30-18=12). Taking all that math into account gives you the commonly accepted number of 200 feet of total cable run between SWM and receiver/client.
What about an amplifier?
Amplifiers don’t work for SWM lines. They should, because they’re digital signals, but they don’t do anything to deal with a big issue with SWM technology. You could amplify the line but you’re not doing anything to deal with latency.
Latency is the time difference between any two things. Like, the difference between the time it takes for a signal to leave the receiver and the time it gets to the multiswitch. SWM is a bidirectional technology. It’s not like regular satellite where the signal comes in, goes down the line and gets to the receiver. Here the receiver is always sending information back to the multiswitch. That’s a key part of how SWM works. When you press the PLAY button in front of your Genie Mini Client, a signal is sent back to the SWM and then to your Genie DVR, then back to the SWM and back to the Genie Client. (In some cases the signal can take a shortcut and stop at the splitter, but that’s not the point.)
An amplifier won’t speed up that time it takes for the signal to get from place to place. With 700 feet of cable going on, it just takes too long for the signal to get somewhere. The receiver or client gets tired of waiting and something just fails. You get an error message, or you lose the picture, or something.
The most frustrating part of this is that it will work sometimes and not others. This makes putting long cable runs in very frustrating.
Amplifiers are only used in SWM installations when you’re going to an apartment and the apartment has a splitter to itself. The amplifier can overcome the losses of the splitter if need be but it won’t compensate for long cable runs.
So what can you do?
If you think you need to run a SWM cable 700 feet, there are some options.
You can put up a second dish on your property and use receivers instead of Genie clients.
You can run 4 cables to the SWM, over a long run like 500 or 600 feet. These can be amplified, since they are before the SWM. Put the SWM where it needs to be.
You can use the DIRECTV app for smartphones and tablets to put video on a distant TV and play programs from your playlist.
These may not seem like perfect options but unfortunately they are the options that are available. If you’re interested in finding out more about custom DIRECTV installations that do actually work, give the folks at Solid Signal a call at 877.312.4547.