[RFI] Tecsun PL-660 for chasing RFI [Was: Is Icom IC-T90a AM-mode good for chasing RFI?]

[Ray, W4BYG]

Am thinking about buying a PL-660 for RFI chasing.  I see by the specs 
it has synchronous detection which is great for SWL apps.  I do not see 
if it has a diode detector option on it.

If it only has synchronous detection, I wonder if there is any 
significant difference between the two AM detectors for tracking down 
RFI noise?

Your attention is appreciated.
Ray, W4BYG