To add to davidandkasies excellent post, for best results the preamp should be as close to the antenna as possible. For a 4-way splitter, you will want something with at least 8 db of gain. Also look for a low noise figure (3 db or less), and doesn't easily overload (100k microvolts or more.) Considering your splitter, coax, and connector losses and such, a Winegard HDP 269, at 12 db of gain might be ideal. More typical is something like a Winegard AP-8700 - which has about 17-19 db of gain. It would also work, but might require a bit of attenuation to avoid overloading your TV sets. A preamp designed to be mounted outdoors on a mast has a separate power supply. The power supply is remotely mounted somewhere out of the weather and sends DC up the coax to power the preamp. You could use something like this. But as davidandkasie says, the power supply will probably want to be on the antenna side of the splitter - since many splitters won't pass the DC through. OTOH, since your antenna is in the attic, there should be a junction box around somewhere were you can install an outlet for an indoor preamp. As far as coax goes, use RG-6 everywhere you can. The new compression connectors are really neat - much better than crimps. But they require an investment in tools. (About $75.) Don't even bother with those stupid 'twist on' connectors.

Day 4 Update: I'm well into phase 2 which is the heat pump portion of the install. Yesterday I removed the old HP and brought the new HP to the site and set it on a new condenser pad. Today's fun project was crawling thru my crawlspace removing old refrigerant line and installing a new 50' lineset. My wife fed me the tubing thru a conduit feedthru I made thru the foundation of my garage right next to the air handler. Surprise #1 The lineset went thru the conduit just fine but hit a stub of a 2X4 hanging below a beam in the crawlspace. It was just a spacer for a water pipe but as luck would have it it was perfectly in line with the conduit feedthru. That was fun cutting off the stub laying on my back. Threading the lineset was slow going because the route was S shaped instead of a straight shot. I had to gradually bend the shape after every 4-5' was fed thru. It's now hung and tie wrapped with nice gradual bends. This time I got lucky since I have about 1-2' extra from a 50' spool. Surprise #2 It was really nice of Mueller to provide a 90 degree ell in the end of the lineset. However it now points 180 degrees from where it needs to to connect to the air handler. Trying to turn 50' of installed lineset 180 degrees just won't happen. I'll guess I'll just have to use a street elbow fitting. Next weekends fun project with be brazing all connections and doing leak testing, evacuation, final charge and checkout. Doing a project like this gives me newfound respect for the pros that do this type of work day in day out.

Consider future use rather than just the room framing project. Most pancakes or portables will handle any nailer. You might want to get a larger cfm'd unit in order to run future tools such as grinders, impact wrenches, cup sprayers, etc., that require higher cfm's. If not, a pancake or portable will handle nailers as well as filling auto tires. If you are out to purchase a nailer as well, it will state the required cfm's. Here's a few from amazon. Most have free shipping. Here is a link that might be useful: air compressor

Thanks for the replies, and sorry for the delay - been away/busy all last weekend and this week. I believe there is a genuine problem with the cable TV cable from my home. It appears the cable tech might be on to something. This afternoon the cable modem kept loosing signal (flapping) frequently. It almost seemed to happen every time the air conditioning came on, and sometimes when it went off. After disconnecting the cable TV cable from my house (i.e. the one attached to my TV's etc) from the cable company splitter outside there were ZERO problems with the cable modem for the rest of the afternoon. So it seems like the cable tech might be sort of correct. The problem has something to do with that cable connected to the TV's etc. Using a digital meter I measure 47.4 ac volts from either the signal (center) wire or the shield on the cable coming from my house to the cable/electrical ground outside at the splitter. Using the same meter I also measure 358 ac micro-Amps from the signal (center) wire and 615 ac micro-Amps from the shield on that cable. This is about 29mW coming from the cable connected to the TVs in the house. I had an electrician check the electrical panel this week, but they really did nothing more than check all connections were tight and voltages etc were normal. They did not find any issues. The incoming cable splitter is grounded to the electrical ground outside. Right now I'm away to check other items, including HVAC connections. Any other suggestions to check?