[Discuss-gnuradio] Unable to find field sync for over the air HDTV signal

[Nirali Patel]

Hello everyone,

I am trying to capture a few seconds of over the air HDTV on a file and then
decode using the files in gr-atsc module according to the instructions in
the README at gr-atsc/src/python. I am using the following command to
capture the signals off the air: /usrp_rx_cfile.py -R B -d 10 -f 587M -g 75
test_file, where 587MHz is the center of the 584-590 MHZ UHF band. I can
successfully capture about 20 seconds of data without any overruns. After I
set up the pipes and start the equalizer, it is unable to find field syncs.
At some gain settings it initially detects field sync but loses it later on.
Am I lacking enough gain/sensitivity in the front-end of the TV_RX? If so
would an lna at the antenna help? Or could I be doing something else that
prevents the equalizer to find field sync? I believe a number of folks must
have decoded over the air hdtv signals using the TV_RX and USRP. Any
suggestions and help appreciated.

Thanks,
Nirali