And the tree.

The tree stays

UHF aerial looks fine, you obviously live in a high signal area.

I see a duplexer on the mast.

If it was me I would run a whole new cable from the antenna to the TV ( RG6 ) and eliminate duplexers and joiners.

As a former aerial installer I always recommend using and installer with the proper tools for the job, believe it or not too much signal can give the same as not enough signal.

I have seen a needle on a signal meter barely move and dropping the aerial down 1m it was more than sufficient.

John

Get rid of the diplexor you don't need it and it will only be creating signal loss.

If it like most old vhf uhf diplexors it will be full of cobwebs dirt dust and water