I would like to axamine this question.
Q. Can I use AP with spectrum expert?
A. Yes. We can connect the machine with any CleanAir capable Ap and it does the same job as spectrum expert. Download the spectrum utility from Cisco.com on local machine and use the CleanAir capable Ap. That is the reason we don't have any new spectrum release. The Spectrum Expert 4 can connect to any Clean Air AP, the AP acting as a remote sensor for your spectrum expert application.
This also allows manual site survey/spectrum analysis without moving a foot !
In reality is not so because I tried to connect Cisco Spectrum Expert to remote sensor in this case to Access Point model 3502I active on WLC with local role and I could only see only the channel that the AP was configurated for example ch11 2472Mhz. It was not possible to view all 13 channel at the same way when I use the external card on the laptop.
If I need to view all the channel is necessary to use external card and not the CAP3502.