TV Antenna Troubleshooting

Pages: 1 2 3 4 »» Next

Your antenna doesn’t meet your expectations. What is going wrong? The place to start is with the symptoms.

Symptom: No evidence of station (No digital lock)

Assuming the station is on the air, the likely causes are:

Weak signal (You might need a better antenna system.)
Interference (See Interference below)
Overload (See Overload below)
Antenna system malfunction

The following experiment will verify that the mast-mounted amplifier is working: Tune the TV to an analog station, then observe the image before and after unplugging the amplifier’s power cord. If there was no change then either the amplifier is dead or there is a bad connection between the amplifier and the power injector. The bad connection could be a short between the coax center conductor and the shield, or it could be an open in either conductor. If AC power makes the image worse then you have overload.

Symptom: Persistent dropouts

On DTV channels you will never see snow, ghosts, or interference, but you will see dropouts. When the signal is corrupted or becomes too weak, you will see “macro-block errors” (parts of the screen that are shifted or obviously wrong) or otherwise known as pixilation, sound dropouts lasting a few seconds, or image freezes lasting a few seconds. All of these errors are crude, unsubtle errors. If these are not present, your image is perfect.

The causes of dropouts are:

Weak signal (You might need a better antenna system)
Interference (See Interference below)
Fading (See Fading below)

Symptom: Day-to-day variation or time-of-day variation

If you are more than 60km from a UHF station the weather will significantly affect the signal strength. At only 30 km a hard rain can diminish a UHF signal. Your antenna must have enough gain to make up these losses.

But if the change in signal strength is sudden and occurs at about the same time each day then you have interference from another station. (See Interference below)

I followed the directions carefully. So why is my antenna too small?

The one problem that usually cannot be predicted is horizon-induced multi-path. This will cause a 3-dimensional pattern of weak and strong spots. See “Short delay multi-path” below.