im surprised ur freeview is working well at all with an indoor aerial, i can only get a signal with an outdoor aerial and lots of clammbering around on the roof to get it in the right direction. an outdoor aerial would help alot they are quite cheap in argos.
we have an outdoor aeriel, and yes, the moped make it go all pixelated. You cant prevent it. Its the same things as someone turning on a hoover and yout tv (analog) goes funny. Electrician told me.
so when the analog signal is switched off in 2010 (i think) will we all have to live with it, a mate of mine gets the same problem but only when a bus goes past, bit of a bummer as we live in london lol
Also ( tho I too am surprised it works with an indoor aerial) just check the lead connections at the end. I had breaking up on mine no matter what I did, and it was only when I re-trimmed the wiring that it really cleaned up.
I am in view of the main transmitters up at Crystal Palace, but despite buying an amplifying aerial, the reception is so bad that I have reverted to analogue while it's still there.