Sounds like a rather large house, but I'd venture a guess that the connectors may be the problem. (poor grounding) Easy fix would be to try installing new connectors at both ends. If that doesn't solve the problem, then the more expensive solution would be to purchase a signal strength meter, (or hire a tv technician) to see how much attenuation takes place in the cable run. Then you would either replace the whole coax, or add an in-line amplifier at the source end to boost signal strength.
Is it split off to other areas of the house? Are those cable runs terminated in another TV or left "open"? I'd talk to your local techs if available, and see if you can get some trunk taps instead of splitters. If your cabling is in a series type configuration, (from one room to the next) a trunk-tap would "tap-off" a portion of the signal, and allow the rest of the signal to pass on through to the final termination.(the kitchen TV) This would maybe compensate for any signal attenuation through the extra coax length, without having to add an amplifier.
signal splitters on the other hand, do exactly that; split the signal in half, 2 equal levels of power or signal strength. If you have a tv in the basement, and it's picture looks good, whereas farther down the line, the kitchen set has poor PQ, then perhaps the basement set could get by with less signal(tap off a portion), and you send the rest where it's needed most... to the kitchen set.
Also if you have unused or "open" ports in your household cable distribution, signal reflections can occur which can cause a reduction in useful signal to the other areas of the house. try adding 75 Ohmn terminations on unused splitter ports to see if that helps improve your kitchen signal.
Hope this is helpful.. I think they might have some signal distribution web sites for further info. Try a google search.