Changing USRP subdevice on the fly

[Moses Browne Mwakyanjala]

Hi everyone,
I wrote a simple program for a usrp b210. I would like to change the RX
antenna on the fly. That is, antenna 0 should be RX2 on Subdevice A:A and
antenna 1 RX2 on Subdevice A:B as shown in the piece of code below. The
problem I face is that I can't change the subdevice on the fly. The
usrp->set_rx_subdev_spec(sRxSubDev)
call doesn't seem to have any effect if it is called more than once. How
should I proceed?

        std::string sRxSubDev;
        switch(m_Settings.m_nTMAntenna)
        {
        case 0:// Using antenna 1
            sRxSubDev = std::string("A:A");
            break;
        case 1:// Using antenna 2
            sRxSubDev = std::string("A:B");
            break;
        }
        usrp->set_rx_subdev_spec(sRxSubDev);
        usrp->set_rx_antenna("RX2");

Thanks in advance,

Moses.