Inline signal booster for long cable run

I live in a condo unit, and I have comcast cable. There is a long cable run with two couplers running to my cable box. Some of my channels will become pixilated but only some of the time. Will replacing the couplers with inline signal boosters fix this issue? If so, what signal boosters should I buy? I've been looking on the web, and most of what I find is for sat, not cable, and I can't determine quality. Finally, do the inline signal boosters require power?

A little background: The long run with couplers was installed before I bought the place and was done because the builder put the original cable drop on the wall opposite where it would be best. I can access this first coupler at the cable drop plate.

From there, the cable is run through other walls, and I cannot figure out where in the wall this cable runs, despite having cut several holes into the drywall.

I found where this intermdiate run terminates, at which point there is another coupler that connects to a final run of cable, which connects to the cable box.

Troubleshooting revealed that a problem lies somewhere in that intermediate run of cable between the two couplers. I determined this by disconnecting the cable at this first coupler and connecting it directly to the cable box via a short 10 foot cable. This produced a perfect picture on the channels that give me problems when full cable run is used. However, I cannot keep this shorter run in place, because then the cable is just laying out on the floor.

My initial inclination was to replace that intermediate cable run with high-quality coaxial, but, as I mentioned, I can't figure out how it gets from coupler one to coupler two. Any help is appreciated on the benefit of an inline signal amplifier.

All signal boosters are powered.

If I understand correctly...

those combiners/splitters are costing you about 7db of signal at the second wall plate. You could replace those with taps which have almost no thru loss so that the first and second wall plate will have an equal amount of signal.

Easier yet would be to call Comcast and have them come out to trouble shoot it.

Do be aware, though, that inside wiring is completely the subscriber's (financial) responsibility, so calling in Comcast could incur a fee, and any work that they do to remedy signal problems inside the premises could also incur a fee. While they often do a lot of that work gratis, that's just a measure of generosity, which cannot be relied on or expected.