Stu C <stu@...>
Either Cat6/7 OR add FT240-31 at both ends, good few turns.
Ethernet radiates 60kHz spikes everywhere in the right conditions, to the point I'm mostly fibre now (in a tiny house).
I once counted the clocks and there were about 14 here, in my house Chinese CCTV cameras being just unspeakble
The Large ferrite FT240 really do clean up the long runs and have enough beef to not get saturated in normal use.
Quite if your 80m constitutes normal use I'm not sure....
Running shielded cable will stop the ferrite interacting fully with the CM field so they are more effective on non.
What I'd do under thatch is a couple of fibre to ethernet adapters and a decent run of fibre.
Actually I'd buy two five port managed (CSS106-5G-1S) switches from Mikrotik, adapters and a 60m fibre - why? if he manage to run the CATx over a sharp object and it later sparks due to RF that is er, awkward....
If he later wants 10G from one end of the cottage to the other the fibre won't need replacing (just the kit at either end).
I know he won't do that for many reasons now but if it does'nt work, revisit this and I'll send wifi-stock.co.uk links.