My slingbox 500 tries to pick up OTA channels that are geographicly near to me but the Channel Master picks up channels that ate farther from me but have stronger signals. What to do?
That doesn't make sense. The Slingbox 500 doesn't have an internal tuner so it cannot pick up OTA channels. It can only stream an output from another AV Device.
Should I change geographical location during set up by using a different zip code?
That won't make any difference. That settings is used ONLY to display the correct program lineup in the guide.