RG6 for subwoofer - Sub goes to sleep and never wakes up....

[computergeek@xxxxxxxxxxx]

I finally finished retrofitting inwall speaker wiring for a 6.1 system
in my family room.  The final piece was the subwoofer.  After reviewing
a number of posts it seemed that RG6 should work fine, and given I've
got a large spool of it just lying around, the price was right.  After
plugging everything back in, much to my dismay, the sub will go into
sleep mode after a period of inactivity and never wake up.  The only
way to get it back is to un-plug and re-plug the line level connector
(powering off the receiver, and/or sub doesn't seem to be enough).
Seems very strange since the strung together pieces of rca patch cables
of the same length (roughly 45') work just fine.  Any thoughts as to
why it misbehaves with rg6?  Should I expect different behaviour from
something like shielded microphone cable?  Any help greatly appreciated.