DP-AMP LPF-1k2 Low-Pass Filter-Module
The LPF-1k2 low-pass filter module is a 5th order Chebyshev
filter in Pi configuration.
Great importance was attached to the selection of high-performance capacitors which not only have a dielectric strength > 2 kV, but are also RF current resistant.
Murata capacitors of class 1 LOW ESR are used.
To further increase the power handling all values are halved, so a 200pF capacitor consists of 100pF capacitors connected in parallel. The coils are all Amidon T130-6 toroidal cores and for the higher bands air core coils. The control is realized by applying a GND signal.
The TRX switching has already been implemented on the filter board and two optional outputs for measuring the TRX and PA output are available. Ideal for converting protection circuits or predistortion on the SDR TRX.
7 filters can be switched: