I have Directv whole house coverage now and this has left several open coax connections. I would like to run at least 100 MB ethernet over coax on the unused connections. This will be on coax that will no longer be connected to the Directv coax signals. I do not want to have powered adapters for the ethernet to coax conversion. The coax runs are no more than 50 feet. Any ideas for adapters? Will the adapters from Directv work? Any ideas that are cost effective? I saw some Dualcomm devices that looked like they would work for about $90.