I've noticed that sometime person's will call my number and the call
will go directly to voicemail.  It happens fairly randomly and does it
whether I'm in the house or in the city (ie much closer to the
towers).

I am running a wireless broadband Alltel K650 in a KR1 wireless router,
properly secured with passwords, etc.
I am set up for dynamic DNS.  For the past several days, I have noticed
that my IP address will remain the same even when I turn the router off