If you’re having trouble with your digital TV picture breaking up, before calling a TV Antenna Guy you should check your TV Fly Lead. This is the aerial cable that connects your TV to the socket on the wall.
TV Fly Leads can easily be damaged internally. You won’t see anything wrong with the cable, but the conductor is broken or the connection between the plug and the cable is damaged. Fortunately it’s easy to check for this. Gently wriggle the cable near each of the plugs while watching the TV picture. If it particularly breaks up badly as you’re wriggling it at one end, that end is probably faulty.
Even if you can’t isolate the issue to an end of the fly lead, if it’s an old or thin one it might be worth replacing. A replacement RG6 Fly Lead will cost about $20 or so depending on length. Cheaper leads will usually also work fine, but are more easily damaged. Either way if it solves the problem it’s much cheaper than having a TV technician come out and replace it!