Are there TVs out there that are specifically designed to be small and portable, and receive over the air signals via antenna and tuner? i.e. Something with a 4" to 10" screen or so?
Alternatively, is there an easy way to turn a netbook or the like into a portable TV showing over the air channels?
Yes. Those 7-10" screens you buy for cars or just to bring on holidays are also available with antennas - Philips make a bunch (but there’s a lot of brands).
But an USB tv-tuner with a small antenna for your netbook/laptop can be bought for next to nothing if you go noname (we recently gave them away to new subscribers) and somewhat more expensive if you want a good brand like Hauppauge.
Just to offer the same service:
How good is the signal on these sort of things? I remember using over the air when I was a kid/teen and it was pretty dodgy reception on most channels. I have heard the new digital signal is much better i/r/t over the air, but haven’t tried it myself.
If you get a clear signal, it’s perfect. If you don’t, it’ll be choppy and pixelated. But static is a thing of the past. It’s essentially all-or-nothing.