Issue with dvbsnoop

Hi

I have been using dvbsnoop for quite a while to get an epg. However it has jjust started hanging when I give a -n value of more than about 300

command
dvbsnoop -s sec -timeout 500-nph -n 1500 0x12

This gets run via a loop which tunes to each available frequency in turn so I dont neccessarily care if each iteration completes as long as it exits.

Any way to stop the hang as I need to get more packets than 300 to get a sensible epg

thanks