Elecraft KXB30 User Manual
ELECRAFT KXB30 30-METER ADAPTER
Assembly and Operating Instructions
Revision A, Oct. 14, 2003. Copyright © 2003, Elecraft; All Rights Reserved
Introduction
The KXB30 adds 30-meter capability to the Elecraft KX1 transceiver. It also significantly improves
performance in the 49-meter SWL band segment (receive only) by re-resonating the KX1's receive bandpass filter at about 6.2 MHz when the operator tunes below 6.7 MHz (with 40 meters selected). Highperformance PIN-diode switches are used to minimize insertion loss and ensure good 30-m sensitivity.
With only a dozen or so parts, the KXB30 is easy to build. The module is installed on the top side of the
KX1's main PC board. The KXB30's filters can be aligned from the bottom side of the board through the
access holes labeled 30A and 30B, so the top cover can be installed prior to alignment.
Specifications
30-m coverage Transmit/receive: 10100-10150 kHz; receive only: 8000-12500 kHz.
Added current drain Approx. 3 mA
Size 1.5" (L) x 0.75" (W) (3.8 x 1.9 cm)
Elecraft • www.elecraft.com • 831-662-8345
Parts Inventory
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Caution: Diodes D1 and D2 can be damaged by static discharge. Before handling
these parts, put on an anti-static wrist strap or touch any grounded, unpainted metal
surface.
The table below lists all parts in the kit. The KX1 Owner's manual has photographs of similar parts.
Ref. Description Qty Part No.
C3 Capacitor, 68 pF ("68" or "680") 1 E530150
C4, C5 Capacitor, 0.1 µF ("104") 2 E530020
C1, C2 Capacitor, 1-40 pF trimmer 2 E540002
D1, D2 Diode, PIN, precision, 5082-3081 (glass) 2 R560014
R4, R5 Resistor, 1 k, 1/8-W, 5% (brown-black-red) 2 E500116
L1, L2, L3 Miniature RF choke, 47 µH (yellow-violet-black)
Note: L1-L3 may be labeled R1-R3 on the PC board.
MISC KXAT1 PC board 1 E100184
MISC Solid, insulated hookup wire, green 1 ft. E760008
MISC Rubber bumper, .04" thick x 0.3" square 2 E980017
3 E690043
Parts Placement Drawing
A drawing showing the locations of components on the KXB30 board can be found in Appendix F of the
KX1 Owner's Manual.
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PC Board Assembly
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A fine-point, temperature-controlled soldering iron (700-800 degrees F) is required to assemble
this kit. A high-wattage iron or one with a wide tip may damage components, pads, or traces. Use a
minimum amount of solder to avoid ground shorts.
the KXB30 will not fit into its position on the RF board. Also, either before or after soldering, all
leads must be flush-trimmed to keep them from shorting to the KX1's inside top cover. Flush-
trimmers are necessary for this, because ordinary diagonal cutters cannot get close enough to the lead
to clip it off right at board level.
component outline. Solder and flush-trim the leads of each capacitor.
position, the rotor plate will be pointing toward the smaller flat side of the trimmer.)
straighten them completely using long-nose pliers.
you press the capacitor down flat against the board, the epoxy coating around the leads may crack or chip
slightly. This will not affect the capacitor's performance. Clean off any residue if this occurs.
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All parts must be installed flat against the PC board, with no extra lead length exposed, or
Install the two 40 pF trimmer capacitors, C1 and C2. Each trimmer should be oriented as shown by its
Using a tuning tool, adjust C1 and C2 so that their rotor and stator plates are fully meshed. (In this
Locate capacitors C3 (68 pF) and C4-C5 (0.1µF). If these capacitors have bent (formed) leads,
Install C3 (68 pF) so that its body is as close as possible to the PC board, but do not solder yet. When
Using a ruler, make sure that the top of the capacitor is no more than 5/32" (4 mm) above the
surface of the board. If it sits higher than this, the KXB30 module will not fit properly.
Bend C3's leads outward slightly to hold the capacitor in place. Solder C3, then flush-trim its leads.
Install C4 and C5 in the same manner as C3. These capacitors must be seated as close to the PC board
as possible. Flush-trim the leads after soldering.
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D1 and D2 can be damaged by static discharge. Before handling them in the next
step, put on an anti-static wrist strap or touch a grounded, unpainted metal surface.
Locate the two small glass diodes, D1 and D2. One end of each diode has a black band, indicating the
cathode end. Install these diodes with the black band oriented toward the banded end of their component
outlines. Solder and flush-trim.
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