Any ideas how good or bad of a reception i would have on a train from Sheffield to Newcastle? I have no experience of portable TVs.

Cheers

You'll probably be travelling beneath the overhead power cables, even if you are travelling diesel, so I wouldn't hold my breath ;)

If you change at Donny to get on a GNER, you may be lucky enough to find they have Wi-Fi though (if you have the necessary equipment to take advantage of that)