Whether you work with big beasts like this SWM-32 multiswitch or just average DIRECTV equipment, you need to know what to expect when setting up your system. You’ll need a signal meter like our AIM Advanced Installation Meter to test, because signal levels are measured in dBm at the frequencies used by DIRECTV satellite systems. That’s not something you’ll be able to figure out with the sort of meters you’ll find at your local electronics “shack.”
Remember that on satellite systems, dB numbers are negative, measuring from -1 to -100 (typically.) So numbers like -50 are very low and numbers like -20 are high. That’s hard to get used to, but eventually it makes sense. dBs are also logarithmic, meaning that a loss of 3dB means a 50% cut in signal and a loss of 10dB means a 90% cut in signal.
Power levels at the dish can vary wildly depending on your location. However, the LNB itself does normalize the signal somewhat. If this is an installation with a separate multiswitch, you are generally ok using the built-in amplifiers on the SWM but if you measure less than -45dBM (in other words like -60) at the input point of the multiswitch you may want to consider the use of an amplifier like the LA144R-T from Sonora. Commercial installations should consider a trunk amplifier like the SA6AL.
Whether it’s a simple SWM-enabled dish or a fancy multiswitch, look for signals to be around –25 to -28dBm at the exit of the multiswitch. If the number is higher (like -21) that indicates a problem with the internal amplification and could be due to faulty equipment. If you are using an adjustable external amplifier you may choose to turn down the level.
As the signal travels down the cable it loses strength. There are several great signal loss calculators out there. (This one at net-comber.com works well without a lot of extra clutter.) If you reach the point where the signal is -45dBm or less (in other words like -60) at the receiver you will begin to have whole-home problems. If it’s below -60dBm you’ll probably have problems with video and audio dropping out.
If you’re not worried about whole-home issues you can use an amplifier like the SWM-A2 to give you a little more distance. However, this amplifier does not help at all with whole-home signals, so you may need to rearrange splitters, move multiswitches or switch to RG11 cable if you want truly long runs for whole home. Here’s a tutorial on diagnosing those problems.
Working with a satellite meter, it should be possible to figure out where the problems lie and address them so your whole system works as expected.