Where to find my Sirius/XM radio antenna/box?

I have an old SkyFi that has a Lifetime on it. I found the Sirius tuner on the firewall just left of the steering column, and there was enough of an antenna lead to route it to the center console where I mounted the SkyFi. After I did mine, I did one for a neighbor, his was a Winnebago, and I found his Sirius receiver behind the surround sound woofer, mounted on the sidewall next to the driver's seat. His also had enough on the antenna lead to route it to the center console.