JJJelectronics- 4 channels Band Pass Filter (BPF)

*2 tuned circuits, give narrow band filter for amateur bands* Frequency: Band 1: 3.4MHz-4.0MHz. Band 2: 6.8MHz – 7.3MHz Band 3: 13.7MHz-14.7MHz. Band 4: 20.8MHz – 21.8MHz*4 way switch to select your band

Tool required.Soldering iron (25w-40w), small cutter, trimming tool

Now let’s build the BPF

I would recommend fitting the parts in the order they appear in the part list.Capacitors first, then coils, .keep all components lead as short as possible.

When you have finished assembly of the board, check all the parts are in the right places.The soldering looks bright and good. Re-solder any suspect joints with a little fresh solder, check that there are no short or splashes of solder between tracks.

Solder 2 pieces of wire to J1 and J2

Capacitor

You will find the capacitors values on a paper with your order

C4, C6, 15 2

C10, C12 20 2

C7, C9 17 2

C8 17 1

C5 15 1

C2,C11 20/ 10 2

C1, C3 10 2

Coils

L12, L13 20m 2

L10, L11, 17m 2

L1, L2 15m 2

L9, L14 10m 2

Solder all coilsSolder the 4 way switch as shown

20m position 10m position

Testing

*When you build your receiver, put you frequency to the center of the band (for example 80m has range from 3.5 to 3.8MHz) so the center frequency will be 3.65MHz).*adjust the BPF for the higher noise, do that for other channels *Or use Spectrum analyzer with tracking generator if you have, adjust the BPF for right frequency and lowest loss * Pictures below are for real measurement