'VV' or 'HV' polarization

Dear all,
‘TOPS Interferometry Tutorial’ used ‘VV’ polarization while we have ‘HV’ as well. I used both. Results by ‘VV’ are perfect but by ‘HV’ are so bad. ‘HV’ intensity is so but while ‘VV’ intensity is perfect. Do you know why?
Cheers,
Marjan