I have an R8600 receiver on the way and would like to get into shortwave listening. I'm a novice when it comes to shortwave antennas and have been doing a lot of reading and research. I would like to try a "random" or Long wire antenna of about 100-125 ft to see how it performs. I noticed the R8600 has an RCA antenna input on the back listed for Long Wire antennas and is 500 ohm. Would this be the antenna connection I want to use? Or would I be better off using the SO-239 connector instead that is listed as 50 ohm? Thanks in advance, Ed.