On Tue, 23 Sep 2008 11:01:53 -0700 (PDT), Art Unwin
wrote:

I would really like something smaller or say
modify something like a audio setup as a project.

Audio spectrum analyzer (free):
http://www.sillanumsoft.org
I use this one on my laptop for audio generating and testing. Try to
get a 96Khz sound card or dongle as the typical internal laptop sound
card is really marginal. No RF, no antenas, but good for audio.

Look into SDR (software defined radio) projects. Most of them will
also act as a spectrum analyzer. For covering bands above 30MHz, use
a mixer and a signal generator:
http://www.rfspace.com/SDR-14.html
I really don't know much about these but they look interesting.

Now, if you have a sizeable bank account, one of the various Anritsu
hand held spectrum analyzers are really nice:
http://www.us.anritsu.com/products/ARO/North/Eng/Spectrum-Analyzers.aspx?lc=Eng&cc=US&rc=ARO&cat=1&cat2=2&ca t3=5&cat4=0

There are also a large number of hand-help CATV spectrum analyzer
available if you want portability. I've only played with a few, so I
can't offer any useful recommendations. They usually don't have
sufficient resolution to seperate HF stations.

Incidentally, in order to use a spectrum analyzer for antenna testing,
you'll need a directional coupler (or VSWR bridge) and an RF sweep
generator.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558