Wiring an older house for HDTV... a few questions

I'm adding OTA HDTV to a house that was built before structured wiring and "home run" cabling. There are three CATV drops made with cheapo steel-core RG59. I'm thinking of keeping these existing CATV connections for locals and adding an OTA antenna for HDTV (Comcast in my area probably won't have any HDTV until 2005) with "all new" cabling using Belden 1624A or 1625. I think I need maximum quality DTV cabling because I'm tucked in close to some mountains and have had to resort to serious reception hardware to get much of anything: CM4228 with 7775 preamp and rotor. It's also nearly 120 feet from one end of the house (master bedroom) to the other (dedicated CRT FP theater).


1) Is it necessary to duplicate all of the cabling or can/should I combine DTV and CATV on the existing cables?


2) Retrofitting the added DTV cabling would be easier if I could put a few "breaks" in the cable. How much loss is incurred with a "barrel" and F-connectors?


3) It turns out that there is a handy 100+ foot conduit between two places I need new cable. It has 120V wiring in a dedicated circuit for smoke detectors (probably mirco-amps). Would it be OK (disregarding any NEC issues) to add the coax into this conduit (re-pull the THHN with the coax)?


4) I know this has been discussed before... but is the 1695 (teflon) cable a worthwhile upgrade from 1694A? The extra cost is not really significant, considering the substantial cost of the whole project.


Thanks for any and all help...


Dave