DC112A internet connection degrade when docked with Aircard 790S

I have an Aircard 790S which i docked on the DC112A Smart Cradle. When I connected my devices to 790S, everything seems fine. DL/UL would be around ~40Mbps/15Mbps. However as soon as I docked Aircard 790S on the Smart Cradle, DL would go down to 1Mbps to 4Mbps at times and UL would be 0-5kbps. On a good day, speed test would see DL at 8Mbps to 20Mbps, but UL stayed below 30kbps.

 

I connected the same external antenna on the 790S to the Smart Cradle. Did factory reset on both as well. No idea on firmware update as both devices seems to be latest on factory reset(V1.0.0.20_1.0.60 on the cradle). I saw two other discussions here but both did not have any solution. 

 

I doubt the issue is with the network since it is always on 4-5 bars at all time(5 bar is the highest).

 

Any feedback/suggestion would be very much appreciated!