1)You have ignition interference on OTA (over the air) digital television? I/E:roof-top antenna? Wow, Since the advent of resistor spark plugs and wires, even analog OTA was relatively interference free here, except for some snowmobiles. With digital, no interference that I've noticed.
2) the vehicles are "blocking" the signal from the antenna. A higher mounting placement for the antenna.
May get better answers, or moved, here: Digital Over the Air (OTA)
help, need to know how I can stop vehicles from interferring with reception, i have a sharp digital antenna converter, and every time my neighbors truck starts up it causes a disruption in the digital signal, is there a box or equipment I need to prevent this from happening, anyone know about this?
I don't think that its car its what car has with it. GPS systems can cause interference when a car or truck goes past my apartment it messes up tv antenna. I live next to a busy road it picks that stuff up all the time.