Air Play / TV as Second Screen, Resolutions

You can get better resolutions than you have obtained. but maybe NOT over-the-air using Airplay.

to get the full manufacturer resolution, connect with a high quality HDMI cable other appropriate cable.

HDMI cables you want for HDMI-only Displays (higher resolutions than 720p TV sets) are marked as Certified with an anti-counterfeiting tag and are labeled:

"Premium High Speed HDMI cable" or that + "with Ethernet"  --OR--

"Ultra High Speed HDMI cable" or that + "48G"

Cables with No Certification tags are good for your standard 720p TV set, and not much more.

Hi Eldermist,

Thanks for contacting Apple Support Communities!

We understand that you need to change the resolution of the TV that is connected to your Mac as a second screen.

You can change the resolution of a connected display on your Mac and may have an option to choose “Show all resolutions” to choose more options. You can learn how here: Change your Mac display’s resolution - Apple Support

"Set the resolution for a connected display

If you have more than one display, additional resolution options are available after the other display is connected.

1. On your Mac, choose Apple menu  > System Settings, then click Displays  in the sidebar. (You may need to scroll down.)
2. Select your display on the right, click the pop-up menu next to Resolution, choose Scaled, then select the resolution you want to use.
3. You may be able to turn on “Show all resolutions” to see additional resolutions for the display."

We hope this helps.

Cheers!