AD9361 LO Leakage


I'm using the ZedBoard+FMCOMMS right now, and I notice that as soon as I set the Tx LO, the Tx channel begins to output that LO at about -10 dBm. When I start streaming my data, I get the expected signal output. But as soon as I stop streaming (by destroying the Tx buffer via libiio), the LO immediately comes back at around -10 dBm.  This isn’t really the behavior I expect or want.  I would expect Tx channel to stop emitting as soon as I stop streaming. I thought it might be a problem with how my software configures things, but I see the same behavior with the ad9361-iiostream ( example. As soon as the application exits, the LO pops up at around -10 dBm right at 2.5 GHz.  Any idea why?

There is a solution I read here in forum that add internal attenuation by adding internal attenuation , the LO leakage really dropped down but with that the desired frequency level also get lowered. 

I'm in FDD mode, btw.

Thank you,