I have a loft aerial (Yagi type (9 verical elements; 2 reflectors,
wideband, directional, and connected to a distribution amplifier)
pointing towards a transmitter (relay) and get good reception (high S
and High Q).

On occasions, usually in the early morning (say 2am), I can receive
some signals from another transmitter that I believe is about 90
degrees to the boom (parent). These signals are not transmitted from
the relay. At other times during the day this signal (parent) is very
weak and unwatchable.

My question is: Is it possible to enahance these weak signals at 90
degrees with little effect to the forward direction?

I would be reluctant to alter the position of the aerial due to my
current exellent reception, and the difficulties of working in the
loft.

It would not be possible to point the aerial at the main transmitter
from the current installation. The best I could do would be to point
the aerial between the transmitters (almost certainy lose all
reception). Although I can receive some signals from the main
transmitter, I am not confident that I would be able to receive all
the multiplexes. People around me all use the local relay transmitter
because of geographical considerations.

Any DIY suggestions?

Thanks