On 06/05/2021 21:10, NY wrote:
I remember we had a set of about 10 attenuators daisy-chained together
between the aerial lead from the wall socket and the one to the TV.

Because there's always some signal pick-up at the TV set itself, strong
attenuation could result in pre- or post-echo in the analogue days. If
the aerial was local to the TV set the result would be signal
cancellation in an unpredictable manner, and that is what happens with
DTT. If the aerial is remote, such as with a distribution system, you'd
see 'ghosts'. However, massive signal levels should appear at outlets on
a system. That's unless the tenant has climbed into the loft and
bypassed a high value tap-off unit!

Incidentally a lot of aerial installers short out braid to inner with
one or two strands rather than use an attenuator. Why? Because they're
stupid.

Bill