Dave wrote:
Do any of you know if there is an available box that can be used on
portable TV's?

Winegard Introduces Battery-Powerer DTV Converter Box
Battery pack would allow DTV-to-analog converters to work in power-outages
By John Eggerton -- Broadcasting & Cable, 8/28/2008 4:44:00 AM MT

Equipment manufacturer Winegard is unveiling a battery pack for its
DTV-to-analog converter box at a DTV expo in Wilmington, N.C. today
(Aug. 28).

http://reviews.cnet.com/tv-hdtv-tune...-33280760.html

Winegard 9-Volt Battery Pack For RCDT09/RCDT09A Converter Boxes (RC-BP9V)

http://www.winegarddirect.com/viewit...wd-rc-12dc.htm

http://www.winegarddirect.com/viewit...wd-rc-bp9v.htm