Two Band Low-pass Filter Kit with Bypass

An easy-to-build two-band filter low-pass kit with optional enclosure. Switching at input and output for improved isolation.

Kit includes:

• High quality double-sided PCB
• SMA sockets x 2
• Switches x 4
   
• Board is designed for all through-hole components (toroids and capacitors not included).

Use your own toroids and capacitors or choose and order them separatly (toroids, wire and capacitors) here at the FUNKBOX shop.

Bypass option makes it a good choice for use with a WSPRlite Classic.

Information for self-designers

The filter board has been designed to accommodate a standard 7 element low-pass filter. The design size for the toroids is T50 but T68 will also fit (not in enclosure). The capacitor footprint is for a 5 mm lead spacing. For good performance (low loss and good attenuation) C0G or NP0 dielectric capacitors should be used (silver mica or polystrene are also good). For flexibility there are footprints for two capacitors in parallel and there are also footprints for capacitors to be placed in parallel with the inductors to allow more complex filter designs to be implemented.

Plated-through holes with cleared roller-tinned copper have been placed along the sides of board. There are also five cleared pads on the ground-plane that can be used for sprung earth contacts if required.

Dimensions 120 x 55 mm. Board includes 4 x 3 mm mounting holes.