Elecraft KSB2 User Manual
Elecraft • www.elecraft.com • 831-662-8345
EL E C R A F T K S B 2 S S B A D A PT E R
Assembly and Operating Instructions
Revision G, July 2, 2011. Copyright © 2011, Elecraft; All Rights Reserved
Introduction
The KSB2 option provides the Elecraft K2 with single-sideband transceive capability. With the KSB2
installed, the operator can use digital communications modes such as RTTY, packet, SSTV and PSK31 in
addition to SSB voice.
The KSB2 includes a 7-pole crystal filter optimized for SSB transmit and receive. This filter is always used
for SSB transmit. During receive, either the fixed SSB filter or the variable-bandwidth CW crystal filter can
be specified for each of the remaining SSB filter settings (FL2-FL4). The SSB filter can also be used for
receive in CW mode if desired. The BFO is individually programmable for each filter, allowing
considerable flexibly in optimizing settings for SSB, CW, or digital modes. Transmit and receive BFO
settings can be adjusted independently in SSB modes if desired.
Other features of the KSB2 include a programmable speech compressor and basic VOX (voice-operated
transmit) capability. In addition, the K2 provides a Carrier Balance mode in which the SSB transmit signal
is routed directly to the receiver. This mode facilitates carrier balance adjustment, and can also be used with
headphones to listen to mic audio whenever the mic gain or compression level is changed.
A wide variety of 8-pin microphones can be used with the KSB2. A mic configuration jumper block is
provided on the Front Panel PC board (see Microphone Configuration for details).
This manual supercedes relevant sections of the K2 Owner's Manual.
Specifications
Crystal Filter Bandwidth approx. 2.3 kHz @ -6 dB; 6/60 dB shape factor approx. 2:1
Carrier Rejection -40 dB or better (typ)
Speech Compressor Compression ratios: 1:1, 2:1, 3:1, 4:1
Current Drain 10-15 mA
Size 4.1 x 2.2 inches (10.4 x 5.6 cm)
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Caution: Some components in this kit can be damaged by static discharge. Before
handling any transistors or integrated circuits, always put on an anti-static wrist strap or touch any
grounded, unpainted metal surface.
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Parts Inventory
The table below lists all parts in the kit. The K2 Owner's manual has photographs of similar parts.
Ref.
Description
Qty.
Components on KSB2 Module
CB,CN
Capacitor, not used (leave open)
0
CC,CM
Capacitor, 27 pF ("27" or "270")
2
CG,CH,CE,CK,
CA,CP
Capacitor, 39 pF ("39" or "390")
6
CF,CJ
Capacitor, 100 pF ("101")
2
CD,CL
Use short wire jumpers in place of these capacitors (see text)
0
C25
Capacitor, 22 pF ("22" or "220")
1
C30, C36
Capacitor, 820 pF ("821")
2
C37
Capacitor, .001 µF ("102")
1
C1-3,C5-12,C16,
C17,C19,C21,C22,
C24,C26,C33,C35,
C39-44
Capacitor, .01 µF ("103"), with 0.1" (2.5 mm) lead spacing.
Note 1: Quantity shown includes one spare.
Note 2: There are also five (5) .01 µF capacitors with 0.2" (5 mm)
lead spacing, listed with Front Panel board components (page 3).
27
C15,C18,C27,
C32,C46
Capacitor, 0.1 µF ("104"), with 0.2" (5 mm) lead spacing
5
C4, C13
Capacitor, 0.1 µF ("104"), with 0.1" (2.5 mm) lead spacing
2
C20,C23
Capacitor, 0.33 µF electrolytic ("0.33" or "334")
2
C31,C34,C50,C51
Capacitor, 2.2 µF electrolytic ("2.2" or "225")
4
C14
Capacitor, 22 µF electrolytic ("22" or "226")
1
C38
Capacitor, 47 µF electrolytic ("47" or "476")
1
D1,D2,D6-14
Diode, 1N4007 (black body)
11
D3,D4,D5
Diode, 1N4148 (glass body)
3
L1
RF choke, 22 µH (red-red-black)
1
P1
Conn., 12-pin male, 0.1" pin spcg
1
P2,P3
Conn., 3-pin male, 0.1" pin spcg
2
Q1,Q2,Q3
Transistor, NPN plastic, PN2222A
3
R8,R10
Resistor, 100 ohms, 5%, 1/4-watt (brown-black-brown)
2
R11
Resistor, 150 ohms, 5%, 1/4-watt (brown-green-brown)
1
R15
Resistor, 180 ohms, 5%, 1/4-watt (brown-gray-brown)
1
R5,R12
Resistor, 470 ohms, 5%, 1/4-watt (yellow-violet-brown)
2
R14
Resistor, 1K, 5%, 1/4-watt (brown-black-red)
1
R6
Resistor, 2.7K, 5%, 1/4-watt (red-violet-red)
1
R2
Resistor, 5.6K, 5%, 1/4-watt (green-blue-red)
1
R9,R16,R23,R24
Resistor, 10K, 5%, 1/4-watt (brown-black-orange)
4
R20
Resistor, 18K, 5%, 1/4-watt (brown-gray-orange)
1
R7
Resistor, 33K, 5%, 1/4-watt (orange-orange-orange)
1
R4
Resistor, 56K, 5%, 1/4-watt (green-blue-orange)
1
3
Components on KSB2 Module, continued
R21
Resistor, 68K, 5%, 1/4-watt (blue-gray-orange)
1
R22
Resistor, 560K, 5%, 1/4-watt (green-blue-yellow)
1
R1
Potentiometer, 1 M trimmer ("105")
1
RP3
Resistor network, 2.0 K, 3 R, 6 pins (77063202 or 980663202)
1
RP1,RP2
Resistor network, 2.7 K, 4 R, 8 pins (77083272)
2
RP5
Resistor network, 47K, 5 R, 6 pins (61473)
1
RFC1,RFC2
Toroidal inductor, 19 turns on FT23-43 core (0.23")
2
T1
Toroidal transformer on FT37-43 core (0.375"), 7:22 turns
1
T2
Toroidal transformer on FT37-43 core (0.375"), 4:22 turns
1
U1
IC, Microcontroller, 16F872 or 16F872A
1
U2
IC, Digital-to-analog converter, 8 bits, MAX522
1
U3
IC, Audio amp/speech compressor, SSM2166 (SMD, pre-installed)
1
U4
IC, Dual comparator, LM393
1
U5
IC, Balanced Mixer/Modulator, NE602 (alt: SA602, NE612, etc.)
1
U6
IC, voltage regulator (6 volts), 78L06
1
X1-X7
Crystal, 4.9136 MHz (matched for crystal filter).
Note: Save the envelope, which is labeled with a calibration value.
7
Z1
4.0 MHz ceramic resonator w/internal capacitors
1
Components on Front Panel Board
P1
Conn., dual-row 16p male, 0.1" spcg
1
C4-C8
Capacitor, .01 µF, 0.2" (5 mm) lead spacing
5
Q3
Transistor, PNP, 2N3906
1
RP3
Resistor network, 10 K, 4 R, 8 pins (77083103)
1
Rbias
Resistor, 10 K, 5%, 1/4 W (optional mic bias; see text)
1
R13
Resistor, 68.1K, 1%, 1/4 W
1
Components on RF Board
J11
Conn., 12-pin female, 0.1" pin spcg
1
J9, J10
Conn., 3-pin female, 0.1" pin spcg
2
Hardware and Miscellaneous
HDWR
Socket for U1 on KSB2 module, 28 pins
1
HDWR
#4 split lock washer (quantity shown includes 2 spares)
6
HDWR
4-40 x 1/4" ZN ST phillips machine screw
2
HDWR
Standoff, 3/16" dia. x 3/8" long, round, 4-40 threaded
1
MISC
Wire, #26 enamel, GREEN
2 ft.
MISC
Wire, #28 enamel, RED
5 ft.
MISC
Wire, #24 insulated, solid conductor
2 ft.
MISC
KSB2 PC Board
1
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Firmware Upgrades
If you received new main-processor firmware (U6 on the K2 control board) along with your SSB adapter,
you should install and test it before proceeding with assembly. The SSB adapter requires main processor
firmware revision 1.04A or later. (Hold any button on power-up to check your revision number.) See
separate instructions that were supplied with the firmware upgrade.
BFO Crystals
If you have a field-test K2 (s/n 1-100), you should have received two replacement BFO crystals. These are
required to allow proper SSB operation. Install the new BFO crystals and any associated components
before proceeding with KSB2 assembly. See separate instruction sheet.
Assembly Overview
The KSB2 module plugs into the K2 RF board at approximately the location shown below.
RF Board
SSB Adapter
As indicated in the parts list, most of the parts in the kit will be installed on the KSB2 PC board. A small
group of parts will be installed on the K2's RF board, and a few on the Front Panel board. The last step in
the assembly process is to wire the microphone connector for your particular mic (P1, Front Panel).
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The KSB2 PC board uses close-spaced components in the crystal filter area to minimize stray signal
pickup. Some capacitors are assigned letters rather than numbers, and some components are not labeled.
Place the KSB2 PC board in front of you as shown below. At the far right end of the board, you'll find an
area with a very symmetrical layout. This area contains the SSB crystal filter and filter switching
components. In the middle of this area are a number of capacitors that are labeled only with letters (A, B,
C, D, E, F, G, H, J, K, L, M, N, P). For example, "A" corresponds to capacitor "CA" in the parts list.
Above and below the crystal filter are the filter switching components. Some of the diodes and capacitors
are not labeled on the board itself, but can be identified in the parts placement drawing below.
The only other unlabeled components are P2 and P3, which will be installed on the bottom of the board.
These are indicated in the upper-right and lower-right corners, below.
All .01 µF capacitors with 0.1" lead spacing use a special symbol with a line between the two pads to
distinguish them from small-value capacitors of the same physical size.
U3 (bottom left-hand corner) is a surface-mount device (SMD) and has been pre-installed.
Parts Placement Drawing
6
KSB2 PC Board Assembly
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A fine-point, temperature-controlled soldering iron (700-800 deg. F, 340-370 deg.
C) is required to assemble this kit, due to the high density of the PC board layout. A highwattage iron or one with a wide tip may damage components, pads, or traces. Use a
minimum amount of solder to avoid ground shorts.
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To avoid difficulties in soldering adjacent components, install components only in
the order described below. Double-check all values before soldering, since removing
small parts from double-sided PC boards can be difficult.
Using the parts list (page 3), identify all of the components that are to be installed on the K2's Front
Panel and RF boards and separate them from the remaining items. Note: The .01 µF capacitors with small
lead spacing (0.1", 2.5 mm) are only used on the KSB2 module, while the .01 µF capacitors with the wider
lead spacing (0.2", 5 mm) will be installed on the Front Panel board.
Install 12-pin male connector P1 on the bottom of the PC board in the position indicated by its
component outline. Do not solder yet. The drawing below shows how P1 should appear viewed from the
left end of the board, with the component side up.
P1 (on bottom)
Solder just one pin of P1 on the top of the board, near the middle of the connector (pin 6 or 7). Verify
that P1 is now perpendicular to the PC board and is seated completely flat. If not, re-heat the soldered pin
and press down on all of P1's pins until the connector drops into place. Once the connector is seated
correctly, solder the remaining pins. This connector must not be tilted or installed at the wrong height.
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All component leads should be kept short to avoid stray signal coupling. The leads on small
capacitors do not need to be straightened, but keep their mounted height at about 1/8" (3 mm) or less.
Install C30 and C36 (820 pF, "821"), near P1 on the top side of the board. Be careful not to confuse
C30 or C36 with C18, which is farther from P1 and has wider lead spacing.
Install C25 (22 pF, "22" or "220"), which is near the right end of P1 (viewed from the top side).
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Install all of the lettered capacitors shown below (CC, CM, etc.). After inserting each capacitor, bend
its leads slightly to hold it in place. Limit soldering time to 2 or 3 seconds per lead, using a minimum
amount of solder to avoid ground shorts.
__CC and __CM (27 pF, "27" or "270")
__CG and __CH (39 pF, "39" or "390")
__CE and __ CK (39 pF, "39" or "390")
__CA and __ CP (39 pF, "39" or "390")
__CF and __ CJ (100 pF, "101")
Install short wire jumpers at CD and CL. Use discarded component leads to form the jumpers. Do not
leave any excess lead length above the board.
Capacitors CB and CN are not used and should be left open.
Install the 0.1 µF capacitors ("104") with 0.1" (2.5 mm) lead spacing.
__C4 (near X1) __C13 (near X7)
Install the 0.1 µF capacitors ("104") with 0.2" (5 mm) lead spacing.
__C15 __C18 __C27 __C32 __C46
Install the .01 µF capacitors ("103") with 0.1" (2.5 mm) lead spacing (C1-C3, etc.). Use the Parts
Placement Drawing to verify the reference designators on capacitors in the crystal filter area that are not
labeled.
__C1 __C2 __C3 __C5 __C6
__C7 __C8 __C9 __C10 __C11
__C12 __C16 __C17 __C19 __C21
__C22 __C24 __C26 __C33 __C35
__C39 __C40 __C41 __C42 __C43
__C44
Note: You'll have one .01 µF capacitor of this type left, which has been included as a spare.
Install C37 (.001 µF, "102"), which is near the microcontroller, U1.
8
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All diodes will be installed vertically as shown below. The anode lead will be inserted into the pad
enclosed by a circle. The cathode lead (banded end) must be folded down and inserted into the adjacent
pad, which is connected to the first pad by a white line. When installing diodes, check the Parts Placement
Drawing as needed to make sure that you're inserting the leads into the correct pads.
Install D3 and D4 (1N4148), both of which are near U5.
Install D5 (1N4148), on the left side of the board near C34.
Install D1 (1N4007), which is located near the middle of the board. As indicated by the short white
line, the cathode lead (banded end) goes into the pad to the left of the D1 label. (There are two other pads
nearby D1, so be careful to use the correct one.) Push the diode down so no excess lead length is exposed.
Install D2 (1N4007), to the left of D1. The cathode lead goes into the pad closest to the D2 label.
Install D6 through D14 (1N4007). Be sure to insert the leads into the correct holes as indicated on the
PC board and the Parts Placement Diagram.
__D6 __D7 __D8 __D9 __D10
__D11 __D12 _D13 __D14
Install resistor networks RP1, RP2, RP3 and RP5. Pin 1 of each network is identified by a dot. This
pin must be inserted into the round pad (the other pads are square). Clip the leads of all resistor networks
after soldering to reduce stray signal coupling. Note: RP3 and RP5 both have six pins, but
different values. Check the labels carefully.
__RP1 (2.7K 8 pins) __RP2 (2.7K, 8 pins)
__RP3 (2.0K, 6 pins) __RP5 (47K, 6 pins)
Transistors Q1-Q3 are all type PN2222A (plastic, TO-92 package). Install these transistors with their
flat sides oriented as indicated by their component outlines. Note that Q2 and Q3 will end up with their flat
sides facing each other when correctly installed.
__Q1 __Q2 __Q3
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