Filter 144 MHz

The filter was tuned with NanoVNA. The attenuation is around 0.5 dB. Input and output impedance is 50 Ohm.

The starting aluminium box.

Both sides were ground to a flat surface. The original gasket
was replaced with a conductive one.

The drilling phase of the project..

The finished filter with the top cover removed.

The detail of one side. The ceramic capacitor is 6.8 pF.
The trimmer is roughly 1...6 pF.

The capacitive coupling must be carefully adjusted..

The completely finished filter.

After some time I began to be curious what the performance of my filter actually is. I measured the professional tuned cavity Rohde & Schwarz type HS to have some comparison:

Obviously the shape of the curve differs, the cavity is more sharp. On the other my filter has a comparable or even higher attenuation at the stop band.

My filter, however, brings these advantages:


< Other Projects
<< Return to Main Page