If you have pixelating pictures & unstable audio from time to time (i.e. "intermittent glitches"), it's likely that something isn't quite right with the antenna system. 

The best thing to do is to call an installer - a directory can be found here: http://www.freeviewnz.tv/equipment-installation/installation.aspx#f...

However there're a few things you could check first:

1. If you're using a UHF aerial, did you do a coverage check with your full street address to make sure that you're actually in the 86% of areas where Freeview|HD (via UHF) has been made available?

• For example, if the coverage check states you're "likely" or "likely with high aerial" to get Freeview|HD, you may need a different UHF aerial than the standard 'grid & fishbone' aerial.  E.g. If you're far away from the transmission tower, a phased array UHF aerial may improve signal reception.

2. If you're using an indoor aerial - I'd recommend changing to an external UHF aerial.  While indoor aerials can work when you're close to a transmission tower & have direct line of sight to the tower, under other circumstances, they're not as robust for picking up signals as external aerials.

3. If you have an external UHF aerial, step outside and take a look: do you have tall buildings or trees in front of the aerial?  Obstructions like hills, buildings & trees can cause signal interference (the signal doesn't have a clear path from the transmission tower to your aerial). 

• You can try moving your UHF aerial to another place on the roof so it has an unobstructed view to the transmission tower (coverage maps showing the sites of transmission towers can be found at the bottom of the coverage page).

4. If you haven't checked the condition of your UHF aerial or satellite dish in a while, it might pay to have a look to see if there're any corroded parts on the aerial / dish.  Remember that NZ does have some pretty extreme weather patterns, and any exposed elements outside the house will be affected over time (e.g. if you're lucky to live near the sea, salt water can cause corrosion quicker on antennae so it's especially important to keep an eye on the aerial / dish).

• Corroded parts can be replaced and are usually inexpensive.  However if you're unsure about how to put it in, please contact an installer.

5. Also do a end-to-end check (from the aerial down to your TV) - a loose connection or cabling that is not well sheltered from other electronic devices can cause signal distortion that result in pixelated pictures.

This is not a comprehensive list at all, just a handful of tips.  Please feel free to add more suggested checks that you've found helpful for you so all viewers can benefit from our collective experience - thanks :)