A larger part of the CWAP exam than you might think, since so much of it is on analysing packets, is diagnosis of various spectrum analyser pictures.
To this end, it is imperative that you download the COLOR views of the diagrams in the book. There is almost no way, unless you are already color blind, to analyze these black and white pictures in the book.
I am hoping that in future editions of the book, that these particular pages will be printed in color.
Off the top of my head I can't remember the website (maybe the download CD'S ?) of where to get these, but be sure you do if you want to pass.
All of the Chanalyzers from Metgeek, are great buys and well worth the cost.
I also suggest that you find and study well, all of the other pictures, especially waterfall diagrams, of every picture you can from every manufacturer that you can find.
If you go to "My Account" on this CWNP website, you can download all the Sybex Companion CDs (all five CWNP study guides). And yes, the downloaded graphics for the CWAP are in color! Ditto as well on Metageek---a great place to study spectrum analysis for CWAP. I also found a few Fluke training videos on YouTube that gave very good training on spectrum signal analysis, using Fluke tools.