144 MHz Schematic



In the picture below, the 2m version has been built "ugly style







432 Mhz schematic



The 432 MHz version has a "notch" at 432MHz added to the 2m version
Essentially it is a 144MHz and 432 MHz filter.

The photo below shows this version built on an etched PCB







The 432MHz Band Pass tuned circuit consists of a loop of wire as shown above that is tuned with a Yellow "Phillips trimmer" that has a maximum capacitance of 10pF.

The TINNED COPPER wire is approximately 20mm long and sits about 3mm above the ground plane.

The 144MHz parallel and series tuned circuits are as above for the 144MHz filter.

Placing some shields as depicted in the photographs below increases attenuation because of increased isolation from input to output.