--- In quizbowl_at_yahoogroups.com, jp_lien <no_reply_at_y...> wrote:
> You see, a crystal radio doesn't need power because it merely
recieves
> radio signals. The buzzers would have to transmit information to
the
> host system, and hence would require transmitters. Transmitters
> require power. Unless you're planning to somehow transduce the
energy
> from the buzzing motion (which probably wouldn't be enough to
> communicate at RF), you need batteries.
>
Um. Radio signals carry energy. Otherwise they couldn't do work on
the antenna. How do you *think* radios work?
Edmund