Total posts : 45366
From your descripton of your situation, I see no advantage to using leaky coax over just a simple wire with a loading coil. Without refreshing my memory about this by reading the rules, I recall the rules for leaky coax are based on field strength and not power. You might search part 15 rules about this but usually the field strength limits, in addition to being difficult to measure, result in less range than the 15.219 provisions regarding power, antenna, ground, and transmission line lengths.
The use of carrier current is intended for campus systems and are also field strength limited. The advantages for a campus which you will not enjoy is that the field strength is specified at the boundary of the campus allowing a pretty strong signal on campus.
Here, I use a SSTRAN feeding a coil loaded antenna tuned to resonance mounted to the ceiling of my basement horizontally. My home is primarily stucco and the hardware cloth and foil faced sheathing underneath form a pretty good Faraday cage, yet I still can hear a strong signal on a cheap portable out to about 150 feet or so (1000 feet on a car radio). Your home may be a better shield than mine so it is not possible to predict what you will experience. A tiny wire extended out one of your windows may perform well.
Keep in mind that many common yard items (patio umbrella poles, poles for bird feeders, clothes lines, etc.) can be used as antennas. I don’t know what leeway you have but maybe you can get some ideas from this. Also, search this site for stealth antennas. There have been many posts here on this topic.