long enough so i grabbed a 10 footer had already. long story short that cable was only a cat5 not even a cat5e which is almost impossible to get a hd signal over. so i put a 18 foot cat6 in its place and would you believe i get picture quality 1000x better.
For "completeness" sake, DIRECTV® DECA is rather at 100BASE-T, so that little1 foot jumper can to the job extremely well. Cat 6 is needed ONLY if you are using long runs on a "giga" network as even cat 5e can do 'giga" speeds.
In other words, you are not gaining ANYTHING by using cat 6. Any improvement means that you either had a bad cable before or is just your imagination and perhaps you having the "monster cable" effect