SIGNAL ANALYSIS -
http://www.tvfool.com/?option=com_wr...9038cfbeda1962
ANTENNA - Winegard 7694 (was recommended here). Aimed to about 280deg, turned to provide best picture, on rooftop mast about 25 feet high
PRE-AMP - CM Amplify adjustable (two settings) on the mast, power inserter is about ten feet further downstream.
DIST AMP - CM 8-port, made no difference good or bad, disconnected
OTHER - There are some trees and buildings in the LOS. Long cable run (100') from antenna to 6-way splitter, then to 5 or 6 sets.
As you see on the report, all major channels are located together less than 20 miles away on a mountaintop, and all appear to have good strength. BUT - while we receive most of them well most of the time, we can almost never get TWO stations (Ch 4.1/ real 35 and 20.1/real 19).
At Channel Master's suggestion we added their adjustable pre-amp; two of the sets now get 4.1, but only sometimes; and, curiously, if the signal is initially good, it degrades over time to frozen/pixelated/unwatchable. The other sets continue to show those two channels as "weak," "unavailable," or just a blank screen.
I realize that, theoretically, we shouldn't have to use a pre-amp or anything else, and that doing so risks overpowering these strong signals. But there seems to be no adverse affect on the channels we do receive, with only an inadequate bit of improvement on the two we don't. I've even tried attaching the incoming cable from the antenna to each set by itself, which should provide the strongest unassisted signal - but even that doesn't deliver the two missing channels.
The engineer at 4.1 (CBS affiliate) was unable to suggest why his signal is somehow different, or to otherwise explain why all the other channels broadcast from the same location and with the same strength reach us just fine but his doesn't.
We are willing to try a different antenna if there is a good chance that will help, but it will be a pain to take down the mast to make the switch. We are unlikely to start replacing TV sets to see if a different brand/model/etc works better than another.
What explains why we cannot reliably or consistently receive two channels that seem, at least on paper, to be absolutely no different than those we do receive well? Is there any hope of a solution that we've not tried?
Thanks for your help...
Mike