@Mikey67 

On which device are the apps you use running? On the tv itself? Or on a device that is connected via hdmi to the tv? In both cases it could be possible you just get stereo. Many older tv don’t support multichannel audio passthrough from hdmi sources. And tv apps on the tv sometimes just support stereo audio. 
You can check the audio settings and set them to Dolby Digital or bitstream if possible. 

I’ve often found rtings.com a good resource to figure out issues with TV pass through data. They’re not perfect, but a good resource in identifying much of this kind of thing. 

Never used apps on the tv.  Fire stick 4k and a stream device.  I’ve looked on the tv I’m assuming and don’t see any place to select dds

Could you post pictures of the settings pages on your TV?

and the actual model number too.

@Mikey67 

Let‘s cross fingers your tvs manual does have info about hdmi passthrough. Anyway imo you should be ready to live with a bad answer. If passthrough isn‘t supported a hdmi switch with audioextractor will be your friend. 

Reading the manual for you, select Dolby Digital:

http://files.sharpusa.com/Downloads/ForHome/HomeEntertainment/LCDTVs/Manuals/tel_man_LC70LE732U_70LE632U_60LE632U.pdf

I’d also suggest not using the Andy Griffith Show for testing, I suspect it is broadcast in mono, not even stereo, and you won’t get a ‘better’ codec from that. Make sure you’re watching a recent movie with an Atmos soundtrack when making these suggested adjustments. The options will often be ‘grayed out’ when the content being watched doesn’t have the necessary data. 

Yea I was just taking menu picks.  I see no options to select pcm or Dolby. I did try optical but no difference 

And this but it does nothing.  

I wouldn’t expect the Food Network to bother broadcasting in anything beyond stereo. I’d still recommend a recent movie that is being broadcast with an Atmos soundtrack, as I said before. 

My stream service has uhd fhd channels. Tried them and firestick 4k.  See no option for Dolby. Or even pcm.  

I’ll try a blue ray on Xbox.  That should tell us something. 

Played blue ray through Xbox last night and fire tv 4k had an audio diagnostic I ran. It showed only pcm  and same on Xbox.  Idk. 

@Mikey67

All your testing imo indicates that passthrough on the tv isn’t supported. 
As supposed the tv manual seems to have no specific information about digital audio out for hdmi sources. 

Thanks. Unless I get better info. I just wonder why have a HDMI arc if it doesn’t improve anything 

On two of my old Vizio TVs, I had HDMI ports that wouldn’t pass a Dolby Digital plus or higher through to the ARC output. The maximum they could pass through was Dolby Digital. Only the internal apps were ‘allowed’ to send out those higher formats. I’ve gotten rid of both of those TVs. 

Yep I see upgrade in my future 

For me was the same like @Airgetlam told. Panasonic tv with hdmi ARC input but no multichannel passthrough from hdmi connected input devices, just multichannel from internal tuner and apps.  
My solution (including Atmos):

FeinTech VAX04101

Let‘s cross fingers your tvs manual does have info about hdmi passthrough. Anyway imo you should be ready to live with a bad answer. If passthrough isn‘t supported a hdmi switch with audioextractor will be your friend. ICA Smart Service

HDMI-ARC was originally literally “optical over HDMI”, so offered the exact same codec support as s/pdif. However, over time a few codecs were added as the bandwidth is a bit better over ARC than optical (DTS+ I think is one such codec).

However, eARC is a big step up over ARC (and optical), tons more bandwidth so supports things like mulit-channel PCM, Atmos, DTS-HD etc.