rtl_fm : Freeze with two -f parameters ?

[mrousse83]

Dear,

I use this command in a Debian system :

rtl_fm -N -f 85.955M -f 173.5125M -s 22.05k -p 65 -l 75 | multimonNG -a SCOPE -a POCSAG512 -a POCSAG1200 -f alpha -t raw /dev/stdin

My terminal freeze...

If i use only one -f, it's work fine !

Did you know how i can fix that problem ?

Thanks.