I think before I spent all that money for something I did not know for sure would work I would order something like this, from Monoprice or online. You can buy two 35 foot RCA's for a total of about $30 plus shipping. I don't know whether these being coaxial are ok for your application but the idea is try some cheaper cable first to see if it works at all. Be careful if you go this route, some cables come as a pair of RCAs that are both in one sleeve.
https://www.monoprice.com/product?p_id=2683
https://www.monoprice.com/product?p_id=2683