This is interesting: Wireless sniffing HDMI display content

potatohead

What is that app they are using?

dgately

Looks like a variant of: https://rtl-sdr.com/tempestsdr-a-sdr-tool-for-eavesdropping-on-computer-screens-via-unintentionally-radiated-rf/

dgately

localroger

It's TEMPEST but for HDMI.

Heater.

Yeah, people were sniffing text off of old green screen monitors and IBM PC screens way back in the day.

Which is why on one project our office had no windows, no phone line or network connection and had to be tens of yards inside the site's boundary fence.

Impressive that it's done with the much higher speed and complex encoding of HDMI.

Wuerfel_21

Very interesting, but likely won't work well with reasonably-sized text with subpixel AA.

Beware of black vans with antennas on top

Heater.

People were complaining recently that the WiFi did not work on their Raspberry Pis. Turned out that at certain resolutions/refresh rates and with cheap HDMI cables there was enough radiated power on the WiFi bands to kill it.

Oddly enough my MS Surface Pro 4 had the same problem. When I hooked it up to my Samsung monitor the WiFi died.