I know there are digital to analog converter boxes that run on 12 volts, and there are probably some others which have power bricks which will convert 120 volt AC to a lower DC voltage but I have not researched this matter.
I was considering it to use my old tv and a converter box, but I wanted a 16:9 format over the 4:3 former standard. I wanted a remote which could control volume and everything else.
It was my opinion and choice to buy a LCD portable that had the ATSC tuner built in, when I found a 12 volt one it was moved to the top of the List.
My new TV uses half the electricity of my Smaller screened CRT TV, and Gets both analog and digital channels. I imagine if I had to power a 12 volt converter box in addition to my old TV, my electrical Usage would be nearly 3 times what I use now to watch TV.
So although there are a multitude of options to power your old analog portable TV and a converter box to receive the future digital only signals, for me the cleanest option was a new ATSC TV.
As I stated on previous posts. If your wanting a portable TV for emergencies it's best to be able to use 12 volts and your vehicles charging system to keep you informed during extended power outages.
Stockpiling D cell or AA batteries is IMO a foolish and convienently wasteful method. Since almost all the portable sized TV's come with car cord adapters, the 12 volt Jumper pack in my post above is the easiest, best longest lasting solution.
They also make the jumper packs commonly called portable power stations that have An inverter included with the Battery.http://www.blackanddecker.com/Produc...Path=4033.4034
This inverter will power all 120 volt AC converter boxes, and the carcord can power the Tv. The battery can be recharged by the wall power or hooking the jumper cables to a vehicles battery and running the vehicle.
It should also be stated that any style of 12 volt battery/ automobile starting battery/ jumper pack/ portable power station should always be kept fully charged. If you run the battery down and do not recharge it right away, In six months when you do goto recharge it, it will not have much capacity left. The instructions will say to recharge monthly even if unused.