The Radio Board.org
If so, I can write one up.
With the arrival of football season, I decided to add a second ceramic filter in series with the first to increase selectivity in the receiver.
The two stations I absolutely needed to receive were only 4kw ERP and 7kw ERP sandwiched in the middle of the band, with blowtorches a couple of channel slots away. On some ocassions, the receiver would try to re-capture on one of the adjacent channels when receiving the low power stations. This did not happen often, but was annoying when it did. The second filter seems to have fixed this. Senstitivity is probably diminished from the extra insertion losss, but this seems to be a non problem. It hears a station on almost every assigned channel. Fidelity seems unaffected.
Interestingly, the AFC works differently with the addition of the second filter. Before, with only one filter, the radio could be set within twenty or thirty KHz of center channel, and the AFC would walk the station in and hold it within a few KHz of center channel. Now the AFC just holds whatever the frequency the radio is tuned to. When tuned to center channel, the AFC will hold it within a KHz of center channel, even on the weak stations.
Thanks for posting. I now have search optimazation correct for google seraches for this board. You'll be able to find articles easier. Even Bing AI finds them now.