A website that catalogued the misbehaviours of the various smart TV operating systems (and the easiest methods of defeat) would be handy here.

E.g. Some TVs will honor wifi off setting. Or alternatively setting the TV to use the Ethernet port.

Or if it needs something on the other end, set up old underclocked Raspberry Pi as a basic router/DHCP server that connects to nothing; power it with TV's USB port.

If you've got a fancy router, connect it to your network with a fixed IP and firewall deny all packets from/to its IP.

If you've got a fancy AP, set up an alternative SSID that connects to an unused VLAN or otherwise routes to nowhere.

A Pi-Hole is good to have in every household. Takes minutes to set up and makes sure that queries to unwanted domains end up in the land of /dev/null

A pi-hole only works against adversaries that rely upon DNS, or haven't been coded to connect directly to "trusted" public DNS servers.

(I'm almost astonished that advertising networks haven't switched to using raw IP addresses everywhere.)

You could probably very easily make a list of the "evil" IP addresses if that happened

You can combine approaches of course. My main in-home DNS, per the DHCP settings on the wi-fi, is a Pi-Hole. Secondary DNS is the pfSense firewall, so nothing's dead in the water if the Raspberry Pi falls over for some reason.

The firewall has the same DNS block-lists as the Pi-Hole, but also has subscription lists of IPs to avoid. Most of those are spammers or malware, but can include whatever other category of malfeasance you desire.

Now we need some DIY guide on how to extract the 5G radio from your TV and turn it into an access point for a laptop.

This will depend on the jurisdiction. In GDPR land neither of this will fly as you obviously don't have consent. I own an Aldi TV which hasn't set up for internet connection. When I first started it I was greeted with a consent form which I declined. I am pretty sure that the setting I did (no internet) is honored both for PR and GDPR reasons.

With 5G, you will have the same problem. And I'd be very reluctant to buy anything stationary which has 5G connectivity.

Unscrew the back of your TV, the internal Wi-Fi antennas may well be be easily identified and disconnected.

e.g.

https://emfaction.userecho.com/communities/1/topics/124-disa...

Fun fact: If the signal is reasonably strong, Wi-Fi will sometimes still work even with the antenna disconnected.

If there is an unwanted and wide-open AP within range of an antenna-less smart TV, you have an unusual problem with countless fun and creative solutions.

I guess it's much less likely if the exposed antenna connector is properly terminated.

Or maybe grounding it? I bet if you mash a little ball of tinfoil into the connector, any residual chance of it working will evaporate.

Who knows? This could make a nice little experiment.

   1. Leave the antenna connected
   2. Unplug the antenna, leave the connector unterminated.
   3. Terminate the connector with ball of tinfoil.
   4. Use a proper impedance matched termination.
   5. Terminate with a proper impedance as close to the wifi chip as possible
   5./b Also cut the antenna trace on the PCB as close to the chip as possible
   Measure signal strength in all scenarios.