Thanks a lot for all the recommendations.
As it turned out, there wasn't a problem with the router, there was a bad
combination of attenuators on the pole outside. (Apparently if there's too
much difference between uplink signal strength and downlink signal strength
that can cause issues. At least that's what they told me at one point.) So
the techs replaced some attenuators, gave me a new cable 'modem'* and my
connection problems are much better (until the next time).

* I hate calling anything a modem that doesn't actually MODulate/DEModulate
an acoustic signal. However, it's the term that most everyone uses, so I
must as well if I wish to be understood.

-- 
Carl Soderstrom
Systems Administrator
Real-Time Enterprises
www.real-time.com