I would like to hook my satellite box to my oppo udp-205 for two channel audio

still go the coax option by inserting a ground loop isolator

I know there are ground loop isolators that are made for CATV, cable TV, but I am not aware of one made for a Satellite Dish. I could be wrong though.

no digital out only rca red and white plus optical output

You have two choices. Digital optical out, or, 2 channel analog out.

30 ft analog RCA interconnects are pretty long. I would think they would really need to be well shielded. Next thing, at about a 2V signal output, what will the signal sound like when it finally reaches the other end of the cables? This would be a question for someone like Al, (almarg) to answer. Or someone with first hand experience.

Safe bet is to go with an optical cable. No doubt it will be cheaper. Trade off? Possibly cold and sterile digital sound. That will depend though on the DAC in the oppo upd and on how reveling your audio system is.

 No doubt though the DAC in the oppo is better than the one in the SAT receiver.

pre is c2300 ,,amp is 7b3,,speakers fs-788,,

I will try the optical first

thanks 

With a long cable I would personally start with the digital coax. More generally, however, inputs are often a scarce resource, so if cable length is not an issue I would use the coax for the source with the highest sound quality (e.g. BD player) and optical for e.g. the television.