Hello, I have come to find out that a channel believed to be encrypted in my town is being picked up by a friend with a digital scanner and a rooftop antenna...are there any handheld antennas (maybe powered) as strong as a rooftop antenna?
No, or I should say....no good handheld antenna (while sitting in your home) will outperform a properly designed rooftop antenna, with high quality, minimal length coax feeding the same radio.
However...you CAN move your radio to a spot nearer the transmitter for the station in question and see how your radio works there.
For example, if your handheld is not capable of de-coding digital transmissions and your friend's is, AND that signal is a digital signal...nothing you do will permit your receiver to decode the signal.