Connection timeouts from pgAdmin

I use the SQL editor in pgAdmin for all of my database work. The
problem I'm having is that after a period of inactivity, pgAdmin loses
the connection to the server. I'm trying to figure out how to avoid
this happening. Not being a network administrator, I'm wondering if
this is related to the tcp_keepalives settings described at
http://www.postgresql.org/docs/8.4/static/runtime-config-connection.html.
Can someone confirm that I'm looking at the right settings, or is
there something else that might cause clients to lose the connection?
The connection seems to be being lost after ~ 15-20 minutes of
inactivity.

Thanks,
--Lee

--
Lee Hachadoorian
PhD Student, Geography
Program in Earth & Environmental Sciences
CUNY Graduate Center