Hi Mike

I would suggest that the problem isnt so much in finding a good antenna
but calibrating the entire system so that you can measure the absolute
signal strength.

That may also involve a screened room and something to dampen the
reflections inside it. Depends on the required accuracy.

But to answer your question, any broadband design would work. It would
be smart though to use something as low gain as possible to avoid
pointing errors. For your purposes it might be possible to use the one
piece of equipment you had measured, take its actual radiated signal and
use that as a relative measure against new equipment.

Lots of websites! My favourite is http://www.cebik.com/radio.html


Cheers Bob VK2YQA

Mike wrote:
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