One thing I notice a lot during contests with my trusty Icom IC-746 (pre pro) is the splatter from power house stations nearby in frequency. I realize I can’t keep their splatter out if it falls within the passband of my receiver. However, I can at least try a more narrow filter to mitigate out of band energy.
The IC-746 comes with a 2.4 kHz wide filters for the first 9 MHz IF and for the second 455 kHz IF along with some wide options for AM and FM use.
I purchased this radio from a CW operator so it was no surprise what I found in the two 9 MHz optional slots: 350 and 250 kHz filters. They work real well for CW and, I suppose, the wider of the two would be good for RTTY work which I am just starting to use.
However, I do lots of SSB work and often get the AGC following the nearby signals rather than the one I want. So I really wanted to try out the 1.9 kHz Icom FL-223. It did not take long to find one on E-Bay from… Taiwan no less. In about a week I had my package.