ON6LEO needed a high power filter for his station. The coaxial filters described here were to much of an effort in a mechanical viewpoint. We also considered the PCB filter design described here but these were never tested on this power level. The PCB filters were the base for this filter. The capacitors were made out of 64 x 64 mm 2mm thick alu plates isolated from the groundplane by 4 layers of 1mm thick teflon. These forming 18pF capacitors.
With a insertion loss of -0.15dB and a return loss of -21dB the filter performed well
The input and output inductor were 3 turns on 11mm with a length of 17mm. The inductor in the middle is 3 turns on 13mm with a length of 19mm. Adjustment of the filter was done by bending / stretching / pushing the inductors.
The filter was build by ON6LEO
The top view of the filter:
The side view of the filter
The bottom view of the filter
See the measurements below:
