Consider the TV you are using also. In the 60's Zenith tube sets were
the hottest RF / IF you could get. Consider this. WMTW TV8 was apx
130 miles. CH 7 was apx 30 miles off the back. CH 9 about 50 miles in the
SAME direction. You could pull out TV8 on rabbit ears. With a big antenna
the pix was a bit grainy but little to no adjacent QRM.
https://www.youtube.com/watch?v=-j_2W6GYMvc
For UHF look into NTSC ATV for hints. It can be touchy to work UHF.
You may find if you have a long run using a QUALITY foam twin lead better. There is a lot less loss with it over coax.
73 Zeno
LFOD !