[StephanieS]

In your situation it's not a signal strength issue per se. You'll notice you have signal strengths in the 60s of (nm) db value. That is a very very good amount of signal.

Your reception situation is likely suffering from a multitude of problems. These range from electrical interference generated within your home (computers, etc.) to signal multipath caused by the signal having to penetrate your roof and bouncing around.

An amplifier is a general term. Specifically there are two types of amplifiers commonly used. One is a preamp that is mast mounted. The second is a distribution amp. The preamp is mounted on the antenna mast below the antenna and amplifies the signal. This is commonly done for very long runs of coax or situations where you have 2 spits in your antenna feed of say, 150' total. This doesn't "improve" reception, instead it offsets losses in your coax from your preamp to your TV(s). In reading this forum's archives you'll find people who when they split their coax, one TV (or both) lost a particular channel(s). A preamp helps offset this.

A distribution amplifier is generally used when you have 3 or more splits in your coax to different TVs. Instead of amplifying the signal at the antenna mast, inside your home where your coax comes in from the antenna, you install your distribution amp. This type of amplifier takes your signal and seeks to offset the losses from splitting the signal 4 ways and adding a bit of amplification to each signal split.

Think of your coax signal as a stream of water. Each time the signal is split, the stream loses velocity. Do that a few times and without assistance (ie, amplification) the stream reduces and becomes smaller eventually dead ending if split too many times without any additional water. TV signal in coax is like this. Not as a extreme, but this is why at 100' of coax one TV sees a signal and at 200' the other TV doesn't. The signal on the 200' run has degraded more.

The pixel problem isn't a signal strength issue in your case. It's a signal interruption issue (ie. attic installation). If you had a RCA ANT751 outdoors and were chasing a 12 (nm) db signal and were were getting pixellation I would tell you there are better antenna choices and you need more gain and a stronger antenna.

Even with a Antennacraft HD1850 or a Antennas Direct DB8e which are regarding as excellent antennas, they can't overcome signal interruption issues.

Your solution is to get the antenna out of the situation where the signals it is trying to receive are being interrupted, or at very least, finding a attic locale that reduces the signal interruption issues.

Cheers.