One reason why a phone's reception can vry is the cell site can
and does issue commands to your phone to turn up or down the
transmitter power.
.6 watts is the maximum output.  It can be commanded down to .1
watts by the cell site.  If the cell site picks you up real loud,
it will tell the phone to drop the power a bit sounds like an odd
combination of location or something.
Call the cell tel carrier's repair service and beef loudly.  If
you get nowhere, try asking the public utilities commissioner to
help figure out if the problem is the phone, flakey cell site
software or just a weird location.
... I haven't lost my mind; it's backed up on tape somewhere!
--- Blue Wave v2.12 [NR]
---------------