cable or broadcast?

Syndication...

so it could have aired on any of your local affiliates, a superstation like WGN, or in first round reruns on SciFi depending on when you found the show

Sheena is currently being aired on cable's H&I (Heroes & Icons) channel on Sundays at 2:00 PM. H&I is usually on a local network affiliate's digital extra channels. They are usually channels with retro content, which can usually be seen with a local antenna and no cable connection.