Before I posted I found these two topics that seemed to hint at interference being an issue for some:
https://forum.hearingtracker.com/t/phonak-tv-connector-interfering-with-wi-fi-signal/55466
https://forum.hearingtracker.com/t/strange-phonak-tv-connector-problems/51730
Over the summer I was watching streaming movies in the evening on a WiFi connected TV using the TV connector and joked with my family that the movies only buffered when I was there: in light of my recent experience and the link above, maybe it was down to the TV connector.
The interference was so bad yesterday that it actually disabled the 2.4GHz channel in use completely on the local router which admittedly is only a few feet from the connector. No devices could connect, my phone included.
I have seen this sort of thing before in my role as a network engineer and it is rare but does happen: i.e one iteration of Apple’s Airport used to take down some Linksys routers just by connecting to them. Audio baby monitors interfere with 2.4GHz whilst video baby monitors annoy 5GHz etc.
This has been a rock solid set up for me that has sent just under 20 million pieces of data over two years and this is the first time that WiFi interference has been an issue.
@sterei
In further testing today I worked out that the connector is frequency hopping to select a clear frequency but not doing a very good job and sometimes selects a noisy value which is the same as the WiFi channel in use. I can either power cycle the connector which causes it to select another frequency or put it in a mylar bag to attenuate the signal.
Putting it in a bag has worked really well for me and only once did the HA streaming connection fail in several hours of testing.
I actually have a brand new TV Connector showing up in a week or two so I can find out if it behaves similarly of if the one on my desk is faulty.