Not impossible but very unlikely. I've installed lots of digital boxes and although I have seen reception off an indoor aerial , it's always been unreliable (ie. picture drops out) or only partial coverage. Then again if you're in a very strong reception area you could be lucky. If you analogue reception is very good with no interference it 'may' work.
An outside wideband aerial designed for digital reception is highly recommended.
Also, the cheap digital boxes (sub £50) are a total waste of time.
To pull in a good signal you'll need a good box (expect £75+).
Check here for advice...
http://www.cai.org.uk/
Check here for coverage...
http://www.dtg.org.uk/retailer/coverage.html
Cobweb
October 2005