[ADTech]

KGO and KNTV are VHF stations, the C4 is a UHF antenna with extremely limited VHF reception.

You could try adding the C2 VHF reflector kit as an add-on (it can replace one of the two C4 reflectors) and see it that resolves the issue, otherwise, it will be necessary to move either add a high-VHF antenna or to start over with a combo 7-51 antenna.

Send me a private message with your name, address, and email address and we'll hook you up with a kit (and instructions) to see if the problem can be easily fixed.