I know this is not exactly the group to post in, but I thought
radio amateurs would have the best ideas for making one's own
antenna. I apologize if this question bothers anybody.

I just spent $800 at an EMC test lab to screen my device for
part 15 compliance. The used a Biconical antenna and a spectrum
analyzer to measure emissions from my device. I was wondering
how inexpensively I could I make my own system for screening?

How hard would it be to make half way decent antenna or antennas that
could listen to a broad spectrum?

Any websites out there have tips on making antennas?

Thanks a lot for your help.
-Mike Dorin