Sorry to hear you are having trouble; it should work if my analysis is correct. Maybe
ADTech will check my analysis.
There is a Channel Master troubleshooting page for the 7777:
http://support.channelmaster.com/hc/...ing-correctly-
What you call a splitter should be the PCT power inserter, and it sounds like you connected it correctly.
If you connected it correctly, then it could be equipment failure, or an unknown source of overload. I gave the link to your FM signals and you should have the FM filter in which is the default position.
http://www.fmfool.com/modeling/tmp/2...c/Radar-FM.png
The FM report that I did was based on my estimate of your location. Please go here and do your own FM report:
http://www.fmfool.com/index.php?opti...pper&Itemid=29
If everything is OK according to the CM troubleshooting page, the only other thing to try is an attenuator between the antenna and the input of the 7777.
If you are having cellular interference, the Antennas Direct Juice preamp is resistant to overload and has a 4G LTE filter to block cellular interference, but it doesn't have an FM filter which could be added.