You have to use a VCR, or a cable box to tune the channel, and then output to RCA. AFAIK, that dongle is for digital audio.

Monoprice has RCA cables in 6", 1', 1.5', 2', and 3' lengths. If you needed to go 80 feet and your only option was 100', I'd support your effort to not have 20' of slack wound up somewhere.

The new Chromecast Audio is neat. But the box only comes with a 1/8th inch aux cable (AKA a headphone cable), so if you want to use that handy little streaming gadget with anything that doesn't ...