I picked up a BCD996XT last weekend and a RS antenna. I installed it in the attic using RG6 --> F connector -> PL-259/BNC adapters respectively. I get better reception then it sitting it on top of my desk, but i'm still not that impressed. Am i losing anything with the RG6 and F connectors? The coax run is 20-25 ft
http://i.imgur.com/MIwBC3Z.jpg
You fail to mention what frequencies you're interested in monitoring (links to them from the RR database will be very helpful!). Since an antenna and associated coax are frequency dependent, an answer for the VHF-Low band (think 30 - 50 MHz) could be quite different from one for the 800 MHz band. Without any specifics, here is some general guidelines based on what is provided.
That antenna is generally designed for the VHF-Hi band, with some performance in the UHF band. If you listen there it should work fine for you. If you listen to the VHF-Low band or 700/800/900 MHz bands you will have limited performance using that antenna (it'll work fine for strong signals, but weak ones may not be strong enough to pick up well using the scanner).
The RG-6 is a 75 ohm coax while your antenna and scanner are both optimized for 50 ohms. While this could be important if you transmit, it will not be an issue for most scanner users. If the tiny fraction of a dB loss is that important to your installation, you have larger issues than the 75 vs. 50 ohm difference. RG-6 is designed to be a low loss coax for use on the standard Broadcast-TV and Cable-TV frequencies. Since the scanner frequencies generally fall between the TV channels, it is a good choice for scanner use.
While adapters do increase loss, if you have quality adapters that are attached correctly you shouldn't see any difference for most scanner installs. If you need half-a-dozen to make your transition from the connector on the coax to where it needs to plug in you may have some noticeable loss. One adapter on each end of the coax, not so much.
The best thing going for you is your 20 - 25 foot run of coax. With that short of a run, unless you have a really bad choice of coax (think that very thin and extremely lossy RG-174) or are trying to listen to frequencies well above 1 GHz your loss isn't going to be enough to worry about.
Things to check out on your install is:
1) is everything tight and installed correctly?
2) is the antenna designed for the frequency you're wanting to use it on (note the phrase "designed for"! Often the designer will create a design that works great on the one or two bands they're creating the antenna for and then the marketing department will write all over the package that it will "Also works on xxx, yyy, zzz" so it will sell more units. Be smart enough to know that "works on" doesn't really indicate that it "works
well on".)
3) are there any nicks, kinks, or other abnormalities in the coax run that indicate it may be damaged?
