Increase in Signal Background

The following graph shows the recently observed increase in our background signal at 97.7 MHz.

This increase in background signal seems to coincide with the launch of HD radio on the New York City station WSKQ at 97.9 MHz. This station was the main contributor to the background signal before its use of HD radio, but HD radio appears to have greatly increased the adjacent channel interference that we detect. This has spoiled the sensitivity of our meteor detection. A possible fix would be to narrow the bandwidth of the FM radio intermediate frequency amplifier stage, possibly by replacing the SAW filters that are used there.