70 MHz Transverter Kits

In case you have a question about a component please contact Ivan, OZ7IS, at "his callsign yahoo dk"


Resistor Nominal value Delivered Colour code
R1, R22 27 kΩ 26,7 kΩ
27,4 kΩ
28,0 kΩ
Red, Blue, Violet, Red, Brown, Red
Red Violet Yellow Red Brown
Red, Grey, Black, Red, Brown, Red
R2 10 kΩ 10,0 kΩ Brown Black Black Red Brown
R3, R14, R18 180 Ω 182 Ω
178 Ω
Brown Grey Red Black Brown
Brown, Purple, Grey, Black, Brown, Red
R4, R7, R25, R29 22 Ω 22,1 Ω
22,6 Ω
Red Red Brown Gold Brown
Red Red Blue Gold Brown 
R5, R19 47 Ω 46,4 Ω
47,5 Ω
48,7 Ω
Yellow Blue Yellow Gold Brown Red
Yellow Violet Green Gold Brown Red
Yellow, Grey, Violet, Gold, Brown, Red
R6, R17 150 Ω 150 Ω Brown Green Black Black Brown (Red)
R8 8,2 kΩ 8,25 kΩ Grey Red Green Brown Brown Red
R9 2,2 kΩ 2,1 kΩ
2,15 kΩ
2,21 kΩ
Red, Red, Black, Brown, Brown
Red, Brown, Green, Brown, Brown
Red Red Brown Brown Brown
R10 1,2 Ω 1,21 Ω Brown Red Brown Silver Brown Brown
R11 5,6 kΩ 5,62 kΩ
5,49 kΩ
Green Blue Red Brown Brown Red
Green Yellow White Brown Brown Red
R12 15 kΩ 15,0 kΩ Brown Green Black Red Brown
R13 1 kΩ 1,00 kΩ Brown Black Black Brown Brown
R15, R16, R24 39 Ω 39(,2) Ω
38,3 Ω
40,2 Ω
Orange White (Red) Red Gold Brown (Red)
Orange, Grey, Orange, Gold, Brown
Yellow Black Red Gold, Brown
R20 22 kΩ 22,1 kΩ Red Red Brown Red Brown Red
R21 3,3 kΩ 3,32 kΩ Orange Orange Red Brown Brown
R23 1,5 kΩ 1,5 kΩ
1,54 kΩ
Brown Green Black Brown Brown
Brown, Green, Yellow, Brown, Brown, Red
R26* 1 kΩ or
680 Ω
1,00 kΩ
681 Ω
Brown Black Black Brown Brown
Blue Grey Brown Black Brown Red
R27 4,7 kΩ 4,75 kΩ Yellow Violet Green Brown Brown Red
R28 12 Ω 12,1 Ω Brown Red Brown Gold Brown Red
R30, R31 82 Ω 80,6 Ω
82,5 Ω
Grey Black Blue Gold Brown
Grey Red Green Gold Brown
VR 250 Ω 220 Ω Horizontal

All resistors are 0,25 W/0,4 W and metal film type.

*: See changes below.


Capasitor Nominal value Marking
C1, C7, C14, C24, C26, C32 120 pF n12
C2, C8, C28 27 pF 27
C3, C4, C30, C31 22 pF 22 or 220
C5, C6, C27, C29 1 pF 1
C9 270 pF 271
C10, C11, C25 33 pF 33
C12 3,3 pF 3.3
C13, C34, C35 39 pF 39J 100V
C15 100 nF polyester, 2-modules 1K63, yellow or grey
C16 1 F, 25 V, electrolytic, axial 10/25V (could also be a bit bigger)
C17, C18 22 F, 25 V, electrolytic, axial 22/25V
C19, C21 82 pF 82
C20 150 pF n15
C22 10 pF 10
C23 47 pF 47
C33 1 nF 1n0, small yellow
C36, C37 12 pF 12p, grey-green black top
C38-C59 10 nF 10n, yellow green top/brown 103

All capacitors are 1 module, 2,54 mm, ceramic types unless otherwise stated.


Component Possible component Delivered
D1, D2 5,6 V zener diode, 0,5 W Blue
D3, D4 1N4004 or equivalent 1N4006, black
D5, D6, D7 1N4148 or equivalent 1N4148, red
IC1 78L08 78L08
Q1, Q8 BF988, BF981, BF900, BF960, BF961, BF964 BF988, BF964 or BF961, text facing down, D long terminal, remember to mount ferrite beads
Q2, Q7 J309, J310, U310 J309 or J310
Q3, Q4 BD442, BD434, BD438, BD136, BD140 BD442, Q3 metal facing west, Q4 metal facing east
Q5 BC337 BC337
Q6 BFW93, BFW92(A) BFW92A, text facing up, C long terminal
Q9 BFR96 BFR96 or BFR96S, text facing up, C long terminal


Inductor Type Comments
DR1, DR8 6,8 H
10 H
12,5 H
Neosid, blue plastic cap, 6.8
Neosid, plain blue plastic cap
Neosid, blue plastic cap, 10
DR2, DR6 12,5 H
18 H
27 H
Neosid, plain blue plastic cap
Neosid, blue plastic cap, 18, or no marking at all
Neosid, blue plastic cap, 27, or no marking at all
DR3, DR4, DR5 Ferrite bead Run a piece of wire through the ferrite beads, big beads
DR7 15 H RF-choke Axial, Brown Green Black Silver
DR9, DR10 (Drain-choke) Ferrite bead To be mounted over Q1 and Q8 drain terminal, small bead
L1, L2, L3, L4, L12, L13, L14, L15 Neosid 00 5231 03 Grey metal housing
L5, L16 Neosid 00 5061 00 Marked 5061
L6, L7, L8 Neosid 00 5048 00 The top is marked with yellow and grey dots
L9, L10, L11 Neosid 00 5049 00 Marked 5049

L1-L16: In case the inductor has a fifth terminal, one that is not located in a corner, cut it away. Please exercise the coil cores before mounting the coils as it helps tuning them afterwards.


MX1, MX2 SBL-1, IE500(A), IE800(F), HPF-505, SMC S-1. Pin 1 is marked with a blue/dark ring
Crystal 42 MHz, third overtone, HC49/U
Metal sheet box 148 x 74 x 30 mm3
BNC-connectors Four BNC-connectors. Remove the four terminals on each connectors.
Feed through capacitors 3 x 1 nF, solderable into a 2,2 mm or 3,2 mm hole
Relay FRT2SB-Sd
Metal sheets Big on top side, small on bottom side
Adjustment tool Light blue
10 cm coax Used in case of separate 28 MHz RX


In order to reduce the leakage from the local oscillator two screens may be installed, one on the top and one at the bottom. The size of the screens are the minimum recommended ones. If you prefer you can make them bigger but it might be a bit difficult to service the transverter later on. These screens should be the last thing you mount on the PCB.

Figure 1. Size of bottom and top screens and how to bend the top screen.

Figure 2. Bottom screen.

Figure 3. Top screen.


Graham, G3LCT, suggests to put a ferrite bead on the drain of Q8, just like on Q1 to prevent instability.

Mark, GM4ISM, suggests to decrease R26 to 680 Ω to reduce the biasing of Q9. There is plenty of linearity on Q9 and lowering R26 will also lower the heat dissipation in Q9. Either R26 can be replaced by a 680 Ω resistor or mount a 2,2 kΩ in parallel with the existing 1 kΩ resistor.

Bo, OZ2M, www.rudius.net/oz2m