WBX Noise floor on 2 meter

I’m running a USRP N200 with WBX which in the 70cm band has a noise
floor of about -110dB on the gnuradio fft. However, I recently started
experimenting in the 2m band and have found that the noise floor is
about 15dB higher. At first I figured that maybe there was just more
noise there but I have a hardware spectrum analyzer which doesn’t
the increase, so I’m thinking this may be either a
USRP/WBX issue or a UHD/gnuradio issue. Any ideas?