In article , nbs wrote:

I'm looking at designing a broadcasting system to broadcast a one way signal
to a receiver within a large building for speech. I don't want it to be
picked up on AM/FM radios and I also need a very inexpensive receiver to
pick up that signal only. I have to admit, I know nothing in this field and
any information would be greatly appreciated.

What is your budget?

You probably should look into cuing transmitters, as used for IFB to
newscasters and the like. Vega makes a very popular system.

You may also be able to use one of the assisted listening systems that
work on the 72 MHz band (not the infrared ones). This will be more wideband
and may be cheaper.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."