updated 03/08/03 12:15 PM

The BPF kit includes 5 plastic envelopes and a schematic.
  1. BPF PCB
  2. Capacitors (do not install until you read special instructions)
  3. Toroids
  4. Headers
  5. Wire

We will build the BPF in this order:
  0. Review instructions. Inspect PCB and parts.
  1. Install ALL trimmer caps.
  2. Wind and install all toroids
  3. Install fixed capacitors
  4. Install headers
  5. Test and align bands


INVENTORY all the parts against the parts list.

NOTE: For reference, there are two types of trimmer caps.

This is the Yellow Plastic coated version shown with Minimum Capacitance
Note the small dots on the inside of the trimmer.

This is the White Cermic version shown with Minimum Capacitance
The solder blob is on the right side of the trimmer.

____Install 18 Yellow Trimmers. These are for 10-30 Meters
    The flat side of the trimmer goes into the square pad

The White Ceramic trimmers need to be "reformed" so that all the
components will fit on the PCB correctly.
Notice the way that the pin on the flat side of the cap is bent inward.
Straighten this pin. Then form the other pin inward. In other words,
reverse the way the pins are shaped.

____Install 12 White Ceramic Trimmers. These are for 40-160 meters.
    The flat side of the trimmer goes into the square pad

____Preset all 30 trimmer caps to mid capacitance position

All dual turn toroids should look like this:
note that the picture shows the leads from top to bottom as
wire on bottom, top, bottom, top

Use this schematic for the parts below. The numbers are repeated
for each band on the PCB

Here are the turns and capacitance values for each band:

BAND    L1             L2          L3             C2,C5,C7   C3,C6
160M    46T:4T:T37-2   47T:T37-2   46T:4T:T37-2   820pF      12pF
        25"#32+4"#32   25"#32      25"#32+4"#32
80M     30T:3T:T37-2   30T:T37-2   30T:3T:T37-2   470pF      6.8pF
        17"#28+4"#28   17"#28      17"#28+4"#28
60M     29T:3T:T37-2   29T:T37-2   29T:3T:T37-2   220pF      4.7pF
        17"#28+4"#28   17"#28      17"#28+4"#28
40M     27T:3T:T37-2   27T:T37-2   27T:3T:T37-2   130pF      3.0pF
        16"#27+4"#27   16"#27      16"#27+4"#27
30M     25T:2T:T37-6   25T:T37-6   25T:2T:T37-6   100pF      2.7pF
        15"#27+3"#27   15"#27      15"#27+3"#27
20M     21T:2T:T37-6   21T:T37-6   21T:2T:T37-6    68pF      1.5pF
        13"#27+3"#27   13"#27      13"#27+3"#27
17M     18T:2T:T37-6   18T:T37-6   18T:2T:T37-6    43pF      1.0pF
        11"#27+3"#27   11"#27      11"#27+3"#27
15M     17T:2T:T37-6   17T:T37-6   17T:2T:T37-6    33pF      1.0pF
        11"#27+3"#27   11"#27      11"#27+3"#27
12M     15T:2T:T37-6   15T:T37-6   15T:2T:T37-6    33pF      1.0pF
        10"#27+3"#27   10"#27      10"#27+3"#27
10M     14T:2T:T37-6   14T:T37-6   14T:2T:T37-6    none      1.0pF
        9"#27+3"#27    9"#27        9"#27+3"#27


____C2, C5, C7
____C3, C6

ALIGNMENT - We can adjust the BPF in the receive mode, but
it is easier and more accurate to adjust them in Transmit mode.
If you have a scope, you can align the BPF without the XMTR pcb
but this method we will do the alignment with ALL 6 MP+ modules connected.
Interconnect all 6 MP+ modules.
We will align the BPF starting at 160 meters and work up to 10 meters.
Connect a dummy load to the 160 meter output on the LowPassFilter.
Apply 12 volt power to the MP+ via an Amp meter.
Current will be anywhere from 250 ma to 1.5 amps.
Set the PLL to 1810 KHz.
Set the trimer caps C1, C4 and C8 at mid point.
Set the Power Out control R18 on the XMTR at the half way point.
Place the FCC into XMIT mode by shorting pins 1 and 2 on the FCC J2
Make sure that the current is less than half an amp.
Adjust C1, C4 and C8 for maximum current. If the current goes above
one amp, cut it back to half an amp via R18 on the XMTR board.
Repeat the C1, C4 and C8 adjustents until tweaked for max current.
As you perform these adjustment, make sure that Q2 and Q3 on the
XMTR pcb do not get too hot. Too hot means you can't touch them
without feeling some pain.
Turn off the XMIT mode and repeat the above steps for the other band
in this order/freqs:
80 - 3560
60 - 5300
40 - 7040
30 - 10110
20 - 14060
17 - 18080
15 - 21060
12 - 24900
10 - 28060
Note that when the MP+ total current is about 950 ma, you should be
generating about 5 watts output into 50 ohms.

Email me ... w8diz at