On Wed, 21 Sep 2011 13:09:58 -0700, Jeff Liebermann wrote:

On Wed, 21 Sep 2011 07:49:49 -0500, dave wrote:

http://www.tek.com/products/spectrum-analyzer/sa2600/ The scope is
running Windows and can constantly compute intermod products (aka
predict spurs) based on the real time environment. It has an option for
advanced wireless signals.

Nice. I didn't know that existed. However, the way it works isn't
anything magic that can't be done with PC controlled spectrum analyzer.
It also seems to have some serious limitations when looking at broadband
noise (i.e. CDMA). The SA2600 looks at the display and records all the
frequencies and amplitudes that it sees. It then computes the likely
intermod products. This would be really cool for sites where carriers
come and go (i.e. frequency hopping trunking systems, cellular handoffs,
FHSS). However, I didn't see anything in the notes on how it would
handle a broadband signal. If it were smart, it would measure the upper
and lower frequencies of the broadband noise, and use that to predict
similar broadband interference bands. However, I couldn't tell from the
destructions if that's what they're doing. The box would certainly be
handy for "monitoring" the receive frequency waiting for the intermod to
appear. Of course the signal levels would need to be well controlled to
prevent displaying mixing products in the SA front end. Much of what I
see in the way of intermod would never show up on a spectrum analyzer.
For example, you're not doing to see PIM on a SA.

I don't think I can justify the cost on the basis of time saved. For
example, I once isolated the source of intermod to another mountain top,
about 20 miles away.

I could never get my boss to buy me one; they are enamored of Rohde Fish
313s.

http://nefl-dstar.com/blog/2010/07/01/the-fsh313-spectrum-analyzer/
$11,000 spectrum analyzer with tracking generator and you're
complaining? You should try using some of my antique test equipment and
see if your opinion changes. I don't think I have anything newer than
about 20 years old.
http://802.11junk.com/jeffl/pics/home/slides/BL-shop6.html

abt $9,200 street with tracking generator. I also had an Aerotron
(Marconi) for the bench. I am no longer keeping MiniCircuits in business.