Colin wrote:
From Canada, when trying to tune in a weak signal from the USA to get
National Public Radio I find that at night and on cloudy days the signal is
clear and fine. I am using a Showgun TV antenna and amplifying it through a
Trisonic 10db 10-900 MHz box.

On bright sunny days, at about 10 am when the sun is rising higher in the
sky the signal gets
gradually worse until there is so much interference that the signal is as
good as lost. In the evening it comes back and is clear again. It appears to
affect only weak stations, the local stronger stations have no interference.

Can anyone tell me what may be triggering this noise? Is there anything I
can do about it?

Maybe there's an intermittent connection that's worsened by the
heat of the sun (when heated, most metals tend to expand. This might
be partially loosening a connection to, or even within, the antenna,
causing the signal to weaken).