Question about 5.1 audio with TiVo Bolt OTA

Hi again folks,

Another question from the newbie. ;-)

So I got the new Bolt, and now have it all set up. I'm very happy with it. Everything works as I had hoped. My question though is, is it possible to get 5.1 digital audio from the HD antenna?

Currently I have the antenna connected directly to the back of the Tivo box, and then an HDMI cable from the TiVo to my Sony AV surround unit. I get sound, but it's not 5.1. It's only coming in as 2 channel audio. I get 5.1 audio from the streaming services (Amazon, Netflx, etc), but not when watching live tv.

Is it even possible to get 5.1 audio from the antenna? If so, any instructions on how to change my set up would be greatly appreciated. :)

Thanks so much!
Kat

P.S. Both the tv and the AV surround unit have toslink capabilities. Should I have hooked that up for the audio?