I use two RC305 receivers connected to a diversity controller in my FPV ground station. This was connected using a cable of about 1.5 meters with 4 RCA connectors and a few DC power connectors. After a while the RCA connector become loose and I don’t trust them. So I decided to replace the RCA and DC connectors with a single connector. In the odds and ends box I found a set of 25-pin D connectors and a plastic back-shell.
Remove one of the AV connectors and the DC connector from each RC305 receiver. I used ribbon cable as its reasonably robust, easy to work and solder and suited the IDC connector.