Unable to receive signal using GNU radio companion

[RRathi]

Hi,

I am trying to capture signal from some satellites and the setup I am using is a USRP B210 connected to an LNB as the antenna.

I am able to correctly receive the signal when I am running rx_samples_to_file example but I am not able to receive any signal when I am running a simple GRC block using the same variable values.

Below is the command I am using for the example code and the GRC.

 /usr/lib/uhd/examples/rx_samples_to_file --freq 1575.0e6 --rate 2e6 --gain 76 --bw 1.024e6 --duration 10 --file rx

In order to verify that the physical setup is correct, I changed the center frequency to a FM station and the receiver port antenna from LNB to a vertical antenna and then I was able to receive signal using both GRC and rx_samples_...

Can someone help me figure out what am I doing wrong.
Any help is appreciated.

Thank you.