Originally Posted by dukkha2
I currently has a CM-4308 antenna gave it to me by the local TV station. I add CM-7777 to it. Put it up 4 days ago.
You are very close to your local transmitters so you should not need a pre-amp. Have you tried the antenna without the pre-amp?
I have no idea what is the function of the FM-trap
The FM radio band is in the middle of the VHF TV band, in fact it's very close to TV channel 6. If you have FM transmitters nearby, they can cause problems with nearby VHF TV channels, or overload the pre-amp and cause problems on other channels. I don't have any FM stations nearby so I have my FM trap set to "off".
and the Combine UHF/VHF port or the VHF separate port on the CM-7777.
If you have separate antennas for VHF and UHF then you would set the switch inside the unit appropriately and connect them to the separate inputs. For a single combination VHF/UHF antenna you leave the unit set "as is" and connect the antenna to the "combined" port.
What should I do to get more HD channel ?
More than what? Based on your ZIP code you should be able to receive at least the local ABC, CBS, NBC, FOX, CW and MNT (MyNetworkTV) stations. Your PBS station (WUNC) surely also has a digital channel with some HD programming, but for some reason it doesn't appear in Antennaweb's default list. That's all you can expect to receive over the air. For other HD channels you have to pay for HD cable or satellite service.