[asterisk-users] Blip every 30 seconds?

[Matt]

Strange issue.... when I record a file from a phone to the asterisk
system I get a blip in the recording every 30 seconds.  It's a very
small blip, but it is there.    It seems like it's only if I'm
recording, not when I'm playing back that the issue happens.

My SATA drives, ETH0, and my Sangoma card are all on seperate IRQs.

Any thoughts on what might be causing this and how to stop it?