The CM4228HD is designed to be a UHF antenna channels 14 thru 51 antenna and also fair a job of receiving the VHF high band channels 7 thru 13 , if the VHF signals are strong.
WRC-DT to the east is REAL UHF channel 48 , virtual number (4.1) NBC.
WHAG-DT to the north is REAL UHF channel 26 , virtual number (25.1) NBC.
The main groups of receivable Digital Tv stations/channels are to the , north east , east , east south.
I recommend aim the CM4228HD antenna at about 75 degree magnetic compass direction.
Here is how to aim antennas ,
http://www.kyes.com/antenna/pointing/pointing.html.
Digital tuners can develop , Digital Glitches , that are not cleared out with a simple channel scan.
Do a Double Channel Rescan ,
http://www.dtv.gov/rescan.html.
I also recommend have only 1 Tv connected for this testing setup.
No splitters , splitters reduce the signal strength.
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How many Tv's are connected??
Is a amplifier being used?? And if so , what is the make and model number.
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As always , trees and tree leaves do a real fine job of reducing or blocking Tv reception and so do buildings and other obstructions including your own house and the roof.
It is best to install the CM4228HD antenna at a location that has the least amount to no amount of obstructions of any type or kind in the directions of reception including the roof and house.
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The CM4228HD antenna can be adjusted for best reception.