time related reception issue
Winegard FlatWave Air VHF/UHF Outdoor Amplified Antenna (60 Mile Range)
50ft RG-6 cable with inline amp (near the TV) included with the antenna
I installed this antenna on the roof of my family member's house with flat face of antenna facing at about 330 degrees (North by Northwest). All the standard VHF channels pull in (2, 4, 5, 7, 9, 11 - virtual stn number). The problem is that Ch 7 starts to breakup after watching for 5-10 min beginning around 4pm. The other channels aren't affected.
Winegard customer service said antenna not built to receive low-VHF. Do not think KGO-TV is Lo-VHF. TV receiver scan produces two 7.1 channels. Tried both, but pixilation and loss of sound occurs sporadically. They suggest calling station or Coit tower (35 miles away), because problem seems to be subject to certain time frame not antenna.
What can I do to get channel 7 better and still keep other channels? Is this the wrong antenna for the job?