KD1JV Designs AT Sprint 3B, Operation And Assembly Manual

Page: 22 / 34

Filter boards:
First, separate the filter boards from the groups of three by snapping along the scored line. You should have five resistors (0805 size, each a
different value) left over from the main board assembly. These will be used on the filter boards so that the processor can identify which
module is for which band. The resistor can only go in one place, near the center of the bottom side of the board. All the other parts will go on
the opposite, top side of the board. Once you have soldered one of these resistors to a board, use the table below to identify which band that
board will be used on. Then cross out or scratch out all the band numbers but the one for which that board is for. See photo below, left. Using
a indelible marker to indicate the band on the component (top) side of the board is also a good idea.
Band 80M 40M 30M 20m 17M 15M
Value 100 K (104) 22 K (223) 10 K (103) 2.2 K (222) 470 (471) 51 (51)
The table below lists the component values used for each band. (value marked on part) 1 turn on toroid = 1 pass through center of core.
Wind wire on the core snugly, but not real tight. Wire lengths allow for ½” max starting pig tail. Note that #32 wire is used to wind the receiver
input coils, this the smaller diameter (thinner) of the two wire sizes supplied.
T-37- 2 = large red, T37-7 = large white, T-30- 2 = small red, T30-6 = small yellow
Tin wire ends before attempting to solder wire to pads on board!
LF3: This coil requires a secondary link winding. The link is wound between the ends of the primary turns.
The best way to do this is to make a small loop at the end of the primary turns, then continue to wind the
required number of link turns. Snip the loop to separate the primary winding from the link and twist the link
wires together so they don't get mixed up with the primary. The link wires go into the two middle holes and the
primary the two outer holes, as shown to the left. If these are mixed up, the trimmer won't peak the coil and
receiver sensitivity will be very bad.
6 pin SIP pins mounted last, be sure it is flush and square to the board. Clip excess pin length and trimmer
capacitor leads after soldering or they may short to lid of tin.
22
Location 80 meters 40 meters 30 meters 20 meters 17 meters 15 meters
C1F 680 p (681) 330 p (331) 220p (221) 150p (151) 22p (22) 22p (22)
C2F 1500 p (152) 680 p (681) 560p (561) 330p (331) 220p (221) 220p (221)
C3F 100 p (101) 68 p (68) 47 p (47) 22 p (22) 15 p (15) 15 p (15)
C4F 680 p (681) 330 p (331) 220p (221) 150p (151) 100p (101) 100p (101)
C5F 100 p NONE NONE NONE NONE NONE
C6F 15 p (15) 4.7 p (4.7) 4.7 p (4.7) 4.7 p (4.7) 2.2 p (2.2) 2.2 p (2.2)
C7F 22 p NONE NONE NONE NONE NONE
CT2 brown brown green green green green
CT3 brown brown green green green green
LF1 T30- 2
23T #30 (12”)
T30- 2
15T #30 (8”)
T30- 2
12T #30 (6”)
T30-6
11T #30 (6)” T30-6
11T #30 (6”) T30-6
11T #30 (6”)
LF2 T30- 2
26T #30 (13”)
T30- 2
19T #30 (10”)
T30- 2
14T #30 (7”)
T30-6
15T #30 (7.5”) T30-6
15T #30 (7.5”) T30-6
12T #30 (6”)
LF3 T37- 2
55T # 32 (28”)
6 T link
T37 -2
45T #32 (26”)
4 T link
T37-7
(white)
50T #32 (27”)
4 T link
T37-7
(white)
42T #32 (24”)
4T link
T30- 2
27T #32 (16”)
3 T link
T30- 2
27T #32 (16”)
3 T link
LF4
RFC BRN/GRY/ BLK
(18) GRY/RED/
GOLD
(8.2)
GRY/RED/
GOLD (8.2) GRN/BLU/
GOLD (5.6) ORG/ORG/
GOLD (3.3) ORG/ORG/
GOLD (3.3)
Trimmer caps: make sure flat side faces line on location outline, towards center of board.