Coaxial cable rejection filters. Three coaxial cable were cut, for the notch frequency of 57.8 Mhz and tuned with the MFJ259 analyzer. As the cable length is critical the cable was directly soldered to the filter components. The coils were also wound and measured on the analyzer, as was the small variable trimmers. It was felt that there may be a voltage break down problem, but none has been experience with operation over several months.

With the filter specification at over two hundred db's, and with sloppy construction methods, it was assumed that the filter should at least be achieving - 150db's loss at 56.7Mhz. The picture shows the finished item which has a close fitting sliding grooved lid. Further, end plates were riveted on to make an RF tight environment. Whilst A full length case could have been accommodated the coax was folded back with ends left OC. Sealant would have effected the Q of the circuit of unknown sealant compounds. Coiling up was also an alternative, but that would have made the case wider. I worked with what material are locally available.