Hello, is it possible to receive anything if I khooked up a cable modem to an IC 8500?
Yes, a bunch of noise.
We run a small cable system at work and have a few hundred cable modems on it. The guy who used to run it was an amateur radio operator. He did a lot of research on the actual modems to see if they could be tricked into doing something other than running data over a cable system.
No dice.
They use space below the lowest TV channel for data communications. Nothing useful, and you won't pick up anything other than a bunch of noise. I also don't know for sure what signal levels are coming out of there, but I wouldn't connect the RF side of a cable modem up to a nice radio like an 8500 without some attenuation in there just to be safe.
Connecting your 8500 direct to the cable system might get you something. Most systems have gone digital, but you might get some FM stations on there. It's been a long time since I had cable TV, but back then they ran the FM radio stations on there. That was well back in the 90's and things have likely changed.