Hello,
we have a problem with several cards R52n-M.
All are characterized by very low sensitivity in 5GHz A the band.
Cards instead of dozens of transmitters in the 5GHz band will find a 1 or 2 at frequencies around 5.6xGHz.
It’s the same for both antenna inputs.
Cards are approximately the same old ( similarly MAC), but differently used.
For example, one of the card now showed up and was running at 5GHz, another was functional and stored in a warehouse and now behaves the same way.
Each antenna output is fitted SE2593A20] Dual-Band 802.11n Wireless LAN Front-End http://www.skyworksinc.com/uploads/documents/SE2593A20_202431A.pdf
I doubt he would break LNA at both inputs practically at the same time.
There is an EEROM 24C32 on the card, you do not know exactly what’s saved, except MAC, of course?
Did not you solve the same problem?