The tuner in your box is standard FREEVIEW with no input from TT.
Could you please expand and clarify what you mean, as I haven't got a clue about what you mean by "switch". A lot of the channels don't broadcast 24 hours a day.
OK for example right now I’m unable to watch BBC1, ITV, C4, C5, More 4, 5USA, ITV3+1; this is just a selection on scrolling through the channels that currently are broadcasting programmes.
I have a message on my TV screen stating Your TV signal is weak or lost.
As mentioned in my first post I can’t receive BBC, ITV, C4 and C5 related channels between 1.00-6.00 am. It’s as if the signal is blocked ???
Is your TV Freeview? If so what happens if you plug aerial directly into TV?
Have you enabled antenna out ? YV Button > Settings > Picture and sound >Antenna out.
The hours you mention are the hours that the box goes into standby if set to SMART mode so try YV button > Settings > Standby & Power > Standby Mode > Always Ready.
None of these are relevant to the issue, particularly if it related to the standby mode surely ALL channels would be affected.
It was just a thought. I don't know then as the tuner card in the TT box is just a DVB2 Freeview tuner card like you can install onto a computer to receive TV so it is not TT related.
As I asked, what happens when aerial connected directly?
The throughput is relevant as if box is in standby there would possibly be no aerial signal from box to TV, but if other terrestial channels working then as you say it's not that.
Have you tried a retune without aerial plugged in, then retune again with aerial plugged in as you could be picking up signals from another transmitter during peak hours which then drop out.
Check out here and put in your transmitter info as this is for Crystal Palace. https://ukfree.tv/transmitters/tv/Crystal_Palace
Have you checked that the transmitter is not undergoing maintenance?