OK,
so I went and bought a spool of quad-shielded rg6 that says "swept to 3ghz" which I'm hoping is the same as the stuff that's rated for 3ghz HDTV signals. I wasn't sure what swept meant.
Ran a new line of coax from the new matching transformer, inside the house, and directly to the TV with the signal meter. Signal was vastly improved!
I then did the test that GroundUrMast suggested, recording the values from the signal meter with the direct line to the antenna, and then re-recording them once I put the splitter back into the equation. I bought a new 4-way splitter, that said it was rated up to 3ghz as well, since my old one said nothing about it.
Here's a pic of the "before splitter" signal readings, compared to the "after splitter" readings. I was suprised it degraded that much, but it appears to be stable on all except the weakest channel. That one gets a bit blotchy every so often. The virtual channels are on the left, with the signal readings (before and after splitter introduction) after them.
http://i243.photobucket.com/albums/f...174944_246.jpg
In regards to teleview's posts, my antenna is actually above my roof, pointed away from the house, to the closest approximation of where the tower is (I don't have a compass). It's 18 feet above ground level, and I could probably raise it another 6 inches, but I ran out of daylight today.
The aerial picture of my house is a bit misleading, as my roof is 2 different colors, due to a color-matched paint flaking off the old part of the house.
Here's a couple pics of how my antenna is positioned:
http://i243.photobucket.com/albums/f...172141_220.jpg
http://i243.photobucket.com/albums/f...172119_640.jpg
To my knowledge, the antenna is not damaged. However, it is nearly 10 years old, and I'm wondering if it would help to take some fine sandpaper to the terminals where I attached the matching transformer....
Thanks SO MUCH for the help both of you had provided.
I have 2 more small questions if anyone's interested: How much would it help my signal if I bought a terminator for the unused port on the 4-way splitter?
Also, is there anything I can do to regain the signal lost by the introduction of the splitter? I would be willing to buy a better amplifier if needed. I've read that the RadioShack one introduces a fair bit of noise.
EDIT: I see that distribution amplifiers are made to combat signal loss from splitting coax cables. The coax packaging I saw today said that 3ghz was needed for HDTV signals, but when I went to research distribution amplifiers, they typically only go up to 1ghz (which I saw was above the frequency range of UHF). Why, then, was the packaging on the coax trying to sell me on getting something rated for 3ghz?