FYI this is the update from the HughesNet technician from the HN Community website.
They have been good about keeping viewers of that site aware of this problem. I hope they can come up with a solution.
"We are continuing to investigate Mountain Lion's behavior. From the outside looking in, it is tough to diagnose somebody else's (Apple's) software. However, what we see is that for individual TCP connections, Mountain Lion stops sending ACK packets regularly, which causes pauses in downloads and overall reduced speeds. If you have multiple connections going at the same time, each is able to get about 1Mbps, so applications (or websites or speed tests) which use multiple connections are less affected.
There are a few kernel settings which can be adjusted on Mountain Lion which improve things, but not drastically. We are hesitant to publish those since they don't seem to address the underlying behavior of Apple's TCP stack - they just mask the symptoms by increasing some of the buffers."
I'm still getting good speeds on my HN9000 using Mountain Lion 10.8.2, so I'm glad it hasn't affected Spaceway service. Today 3989 Down/234 Up.--
Upstate NY HN9000 Apple Airport(802.11n)/ Mac OS X 10.8