Elecraft KAT100 User Manual

Elecraft

KAT100

Revision C, March 12, 2003

Automatic Antenna Tuner

KAT100-1 shown above. See page 3 for photo of full-height version (KAT100-2).

Table of Contents

Introduction ................................................................................................................................................................................................................3

Parts Inventory...........................................................................................................................................................................................................4

RF Board Assembly .................................................................................................................................................................................................8

Front Panel Board Assembly................................................................................................................................................................................18

Final Assembly........................................................................................................................................................................................................19

Alignment and Test ................................................................................................................................................................................................27

Using the KAT100...................................................................................................................................................................................................31

Troubleshooting......................................................................................................................................................................................................34

Specifications..........................................................................................................................................................................................................36

Circuit Details..........................................................................................................................................................................................................37

Schematic ............................................................................................................................................................................................. APPENDIX A

Parts Placement Drawing ..................................................................................................................................................................APPENDIX B

Introduction

Tilt-Stand Options

The KAT100 automatic antenna tuner (ATU) is designed for use with the Elecraft K2/100 transceiver, as well as the basic K2. It can match loads with SWRs in excess of 10:1, and can easily handle 150 watts of transmit power. Ten front-panel LEDs provide an accurate, real-time SWR indication during transmit. The KAT100 also includes two antenna jacks–the equivalent of two auto-tuners connected to the rig.

Because of its tight integration with the K2, the KAT100 offers many advantages over generic external auto-tuners:

• Automatic power reduction to 2 or 20 watts (in low- and high-

power modes) when the K2's possible with as little as 0.2 watts in low-power mode

• Direct display of power, SWR, and other data on the K2 LCD

• ATU can be configured using the K2 menu

• K2's POWER control setting indicated by two LEDs

• K2's

• L/C settings stored in EEPROM for both antennas on all bands

• SWR LEDs can use bar or dot mode (set by G R P H menu entry)

• All LEDs have two brightness levels (set by L C D menu entry)

The ATU comes in two enclosure styles, both of which match the K2:

A N T 1 / 2 switch selection indicated by two LEDs

T U N E switch is pressed; auto-tune is

Two different matching tilt stands are available, one for each KAT100 type. The E T S 2 is our standard, full-height tilt stand (2.5"), and is recommended for use with the KAT100-2. The E T S 1 5 is identical to the ETS2 but is only 1.5" tall. It's ideal for use with the low-profile KAT100-1, providing the optimum viewing angle during operation.

Pre-Wound Toroids Available

The toroids in the KAT100 kit are not difficult to wind, and detailed instructions are provided (beginning on page 13).

If you prefer not to wind the toroids yourself, you can obtain a full set of pre-wound toroids (with leads stripped and tinned) from an Elecraftqualified source. Ordering information is at www.elecraft.com.

You do not need to send your cores or wire to the winding service. You can keep your set for replacements or for use in your own projects.

• The KAT100-1, shown on the cover of this manual, is housed in a

low-profile cabinet, intended to be placed beneath the K2. Two anti-slip brackets are provided, so the K2 will remain in position even if the KAT100-1 is tilted up. (Also see Tilt-Stand Options at right).

• The KAT100-2, shown in the photo at right, is intended for side-

by-side arrangement with the K2. It includes front and rear panels

that match our K2-sized EC2 enclosure kit. (The EC2 is sold separately.) The EC2 cabinet provides plenty of room in the top cover for your own accessories.

Both KAT100 types are covered in this manual.

KAT100-2

Parts Inventory

You should do a complete inventory, and if you find anything missing, contact Elecraft.

Leave painted panels wrapped until they are needed during assembly. This will protect the finish.

Items supplied only with the KAT100-1 (with low-profile enclosure).

Picture Ref. Designator(s) QTY Description Part #

MISC 1 KAT100-1 Front Panel E100138 MISC 1 KAT100-1 Rear Panel E100139 MISC 2 KAT100-1 Side Panel E100140 MISC 1 KAT100-1 Top Cover E100146 MISC 1 KAT100-1 Bottom Cover (note: includes holes for optional feet/tilt-stand) E100147

The items below are in a small bag labeled "Misc., KAT100-1" (p/n E850132)

HDWR 28 Screw, 4-40 x 3/16" Panhead Phillips, black (includes several spares) E700015 HDWR 8 2-D Fastener E100078 MISC 4 Rubber foot, self-adhesive E700024 MISC 2 Anti-slide bracket E100150

Items supplied only with the KAT100-2 (for use with an EC2 enclosure).

Picture Ref. Designator(s) QTY Description Part #

MISC 1 KAT100-2 Front Panel, EC2-compatible E100142 MISC 1 KAT100-2 Rear Panel, EC2-compatible E100143

The items below are in a small bag labeled "Misc., KAT100-2" (p/n E850136)

P3, P6 2 Connector, 2 pin male, 0.156"spacing (Aux 12V In and Aux RF Out) E620012 P 4 1 Connector, 10 pin (5x2) male, 0.1" spacing (Aux Control) E620040

Items in the KAT100 main parts bag (E850094), supplied with both KAT100-1 and -2. Color codes and markings are shown in parentheses.

Reference designators from 101 up refer to Front Panel components. Refer to Appendix A of the K2 owner's manual for more parts photos.

Some components in this kit can be damaged by static discharge. Before handling diodes, transistors, and ICs, touch a

grounded, unpainted metal surface, or use a wrist strap grounded through a 1 megohm resistor.

Picture Ref. Designator(s) QTY Description Part #

C1 1 Capacitor, 12 pF, 2000V ceramic (3 KV caps may be substituted for any 2KV)E530107 C2 1 Capacitor, 22 pF 2000V ceramic E530108 C3 1 Capacitor, 39 pF 2000V ceramic E530109 C4 1 Capacitor, 82 pF 2000V ceramic E530110 C5,C6A,C6B,C7A-7D 7 Capacitor, 150 pF 2000V ceramic ("151") E530111 C8 1 Capacitor, 1200 pF, 1600V polypropylene film ("122") E530112 C32 1 Capacitor, 100 pF, 200V ("101") E530034 C33-36,C47 5 Capacitor, .001 µF, 50 V ("102") E530001 C37,C38,C39,C45,

C46 C50,C51, C44,C49,C101,C102,

C56 C9-30,C40,C41,C43,

C48,C52-55,C57-60 C42 1 Capacitor, 10 µF, 35 V electrolytic E530045 C31 1 Capacitor, 5-30 pF trimmer E540001 D1,D2 2 Diode, 1N5711 (small glass body) E560004 D3,D4 2 Diode, 1N5817 (large black body) E560008 D110,D111,D112 3 Rectangular LED, Red (long lead is anode -- see text) E570007 D101,D103,D104,

D105,D106,D113 D102,D107,D108,

D109,D114 E1 1 Screw terminal, right-angle PCB mount E700012

7 Capacitor, .01 µF, 50 V ("103") E530009

5 Capacitor, .047 µF, 50V ("473") E530025

34 Capacitor, 0.1 µF, 50V ("104") E530020

6 Rectangular LED, Green E570008

5 Rectangular LED, Yellow E570009

J1 1 Connector, DC barrel jack, 2.1mm, right-angle PCB mount E620026 J2 1 Connector, BNC, right-angle PCB mount, with finishing nut and washer E850134 J3 1 Connector, DB9-F (female), right-angle PCB mount E620058 J4,J5,J6 3 Connector, SO239 E620064 J7 0 Connector, 6-pin female, 0.1" (not supplied; for future use) N/A J101 1 Connector, 12-pin female, 0.1" spacing, PCB mount E620008 K1-K18 18 Relay, SPDT, 10A rating E640012 L1,L2,L3,L4 4 Toroidal inductor on T80-0 core (brown, 0.8" dia.); see text E680020 L5,L6,L7,L8 4 Toroidal inductor on T94-2 core (red, 0.94" dia.); see text E680018 P1,P2 0 Connector, 2 pin male, 0.1" spacing (not supplied; for future use) N/A P 5 1 Connector, 12 pin male, 0.1" spacing, right-angle mount E620065 Q1 1 Transistor, PNP, modified TO-92 package, Zetex ZTX789A

Note: Q1's labeling may be hard to read. The part number should be marked

on the silver-colored side. Q2,Q3 2 Transistor, MOSFET, TO-92 package, 2N7000 E580002 Q101,Q102 2 Transistor, NPN, TO-92 package, PN2222 E580001 R5,R101-R114 15 Resistor, 120 ohms, 1/4W, 5% (brn-red-brn) E500022 R2 1 Resistor, 200 ohms, 1W, 5% (red-blk-brn) E500074 R115 1 Resistor, 220 ohms, 1/4W, 5% (red-red-brn) E500002 R116 1 Resistor, 470 ohms, 1/4W, 5% (yel-vio-brn) E500003 R11 1 Resistor, 680 ohm, 1/2 W, 5% (blue-gray-brn) E500085 K2 CTRL-R12 1 Resistor, 820 ohm, 14 W, 5% (gray-red-brn) E500001 R1,R8,R9 3 Resistor, 3.3K, 1/4W, 5% (org-org-red) E500017 R12,R16,R17,R18 4 Resistor, 10K, 1/4W, 5% (brn-blk-org) E500015 R3,R4 2 Potentiometer, 100K trimmer ("104") E520001 R6,R7,R13 3 Resistor, 8.45K, 1/4W, 1% (gray-yel-grn-brn) E500071 R15 0 Resistor (not supplied; for future use) N/A RFC1 1 RF choke, 15µH (brn-grn-blk) NOTE: may be in bag with toroid cores E690012 RFC2 1 Toroidal inductor on FT37-43 core (gray, 0.37" dia.); see text E680003 RP1 1 Resistor pack, 3.9K, 4 individual resistors, 8 pins E510000 T 1 1 Transformer on FT50-43 toroidal core; see text E680008 U1 1 IC, Programmed microcontroller for KAT100, PIC16F877 or PIC16F877A E610012 U2,U3,U4,

U101,U102 U5 1 IC, op-amp, LM358 E600010 U6 1 IC, high-current op-amp, EL5146C E600041 U7 0 IC, EEPROM, 25LC320 (not supplied; reserved for future use) E600009 U8 1 IC, 5V regulator, TO-220 package, 78M05 or 7805 E600024 W1-W7 0 Wire jumper (leave open except as specified in text) N/A Z1 1 Ceramic resonator, 4.0MHz, 0.2% tolerance (orange, with 3 leads) E660001

5 IC, octal driver, TPIC6B595 E600032

E580019

HDWR 2 L-bracket, front panel retainer, 4-40 threaded E700073

HDWR 14 Screw, 4-40 x 3/16" Panhead Phil, black (2 spares) E700015 HDWR 15 Screw, 4-40 x 5/16" Panhead Phil, zinc plated (2 spares) E700077 HDWR 1 Thumb screw, 6-32 x 1/2", with black plastic knob E700070 HDWR 1 Nut, 6-32 E700069 HDWR 2 Flat washer, #6 E700067 HDWR 24 Split lock washer, #4 (2 spares) E700004 HDWR 15 Nut, 4-40 (2 spares) E700011 HDWR 3 Solder lug E700062 HDWR 2 Standoff, hex male-female (for DB9 connector, J3) E700078

MISC 1 Connector, 2.1 mm mating plug for J1 (DC barrel jack) E620032 MISC 1 Connector, 9-pin, DB9M (male), solder cup terminals (for control cable) E620049 MISC 3 ft. Cable, 4-conductor shielded E760009 MISC 1 DB9 backshell and hardware (for control cable) E620050 MISC 1 40-pin socket for U1 E620017 MISC 1 ft. Hookup wire, #20, black insulation E760006 MISC 1 ft. Hookup wire, #20, red insulation E760007 MISC 4 ft. #26 enamel wire for T1 and RFC2, red E760002 MISC 2 ft. #26 enamel wire for T1, green E760004 MISC 20 ft. #20 enamel wire for L1-L8, red E760022 MISC 1 0 Cable ties (for L1-L8; 2 spares) E980002 MISC 1 Sand paper E850090 MISC 1 KAT100 RF PC Board E100144 MISC 1 KAT100 Front Panel PC Board (may be wrapped with one of the panels) E100145

RF Board Assembly

Place the KAT100 RF PC board in front of you, with the bottom side up and the front edge facing you as shown in the Parts Placement Drawing, Appendix B.

On the bottom of the board, along both edges, you'll find six locations for 2-D fasteners. These are used to secure the RF board to the chassis panels. In the next few steps, just four 2-D fasteners will be attached, and the remaining two locations will not be used. Which four locations to use depends on whether you're building a KAT100-1 or KAT100-2:

Install 2-D fasteners at the four locations identified earlier, on the bottom of the RF board. Secure each fastener from the top side of the board with 3/16" (4.8 mm) pan-head screws (black) and #4 split lock washers (Figure 1b).

Make sure the 2-D fasteners line up with the edges of the PC board and do not hang over. If they hang over or do not match their component outlines, they are installed backwards.

The leads on small capacitors are fragile. Do not pull on

the leads or bend them excessively.

KAT100-1: Use the two 2-D locations near the front edge, and the

two near the back edge.

KAT100-2: Use the two 2-D locations near the front edge, and the two located about two-thirds of the way back. (The 2-D fasteners are supplied with the EC2 enclosure kit, not the KAT100-2.)

Locate a 2-D fastener and hold it vertically (Figure 1a). Looking at a side with two holes, note that the holes are offset from the center. The PC board outlines for the 2-D fasteners have a matching offset, which will aid in installing them in the next step.

Holes offset

from center

(a)

Figure 1

(b)

Sort all capacitors into groups by physical appearance (size, color, and lead spacing). Within these groups, sort them by capacitance value.

Locate the component outline for capacitor C55, on the top side of the board near the front edge.

Install a 0.1-µF capacitor (labeled "104") at C55. Keep the lead length as short as possible. (If the leads are pre-formed, the capacitor may sit slightly above the board.)

Bend C55's leads outward on the opposite side of the board to keep it from falling out or shifting position. Then solder the capacitor and trim the leads.

Note: Components may be soldered one at a time or in groups. Leads can be trimmed either before or after soldering. After soldering, trim leads to about 1/16" [1.5 mm] or less in length.

If your solder joints are not clean and shiny, your iron

may not be hot enough, or you may be using the wrong type of solder. These "cold" solder joints will likely result in poor

performance, reliability problems, or component failure. You may wish to consult our web site for additional soldering

instructions and tool recommendations.

In the steps that follow, you'll be installing groups of components. When working from a long list, install all of the items on one line before moving on to the next. Arrows (⇒) appear in the list

to remind you of this order. In general, assembly proceeds from left to right and front to back across the board.

Install the capacitors listed below. Start with C29, which is to the

left of C55, near relay K16. Check each capacitor's labeling

carefully (shown in parentheses).

Install the high-voltage capacitors listed below.

Note: Save a few of the clipped leads from these capacitors for use as ground jumpers in later steps.

__ C1, 12 (12) ⇒ __ C2, 22 (22) ⇒ __ C3, 39 (39) __ C4, 82 (82) __ C5, 150 (151) __ C6B, 150 (151) __ C6A, 150 (151) __ C7D, 150 (151) __ C7C, 150 (151) __ C7B, 150 (151) __ C7A, 150 (151)

__ C29, 0.1 (104) ⇒ __ C26, 0.1 (104) ⇒ __ C25, 0.1 (104) __ C24, 0.1 (104) __ C23, 0.1 (104) __ C22, 0.1 (104) __ C21, 0.1 (104) __ C20, 0.1 (104) __ C19, 0.1 (104) __ C60, 0.1 (104)

__ C51, .01 (103) __ C50, .01 (103) __ C39, .01 (103) __ C40, 0.1 (104) __ C38, .01 (103) __ C46, .01 (103) __ C37, .01 (103) __ C48, 0.1 (104) __ C43, 0.1 (104)

__ C9, 0.1 (104) __ C18, 0.1 (104) __ C17, 0.1 (104) __ C16, 0.1 (104) __ C15, 0.1 (104) __ C14, 0.1 (104) __ C13, 0.1 (104) __ C12, 0.1 (104) __ C11, 0.1 (104) __ C10, 0.1 (104) __ C52, 0.1 (104) __ C53, 0.1 (104)

__ C45, .01 (103) __ C54, 0.1 (104) __ C36, .001 (102) __ C35, .001 (102) __ C41, 0.1 (104) __ C58, 0.1 (104) __ C44, .047 (473) __ C49, .047 (473) __ C56, .047 (473) __ C57, 0.1 (104) __ C47, .001 (102) __ C59, 0.1 (104)

__ C33, .001 (102) __ C34, .001 (102)

__ C32, 100 pF, 200V (101)

__ C28, 0.1 (104) __ C30, 0.1 (104)

__ C27, 0.1 (104) Near K17, middle of board

__ C8, 1200 pF (122)

Install the electrolytic capacitor, C42 (10 µF), near the back-right corner of the board. The (+) lead must be installed in the hole marked with a "+". The (+) lead is usually longer than the (–) lead, and the (–) lead is identified by a black or white stripe.

Install the 5 to 30 pF ceramic trimmer capacitor, C31, near the back edge of the board. Orient the flat side of the trimmer as indicated.

Using a small flat-blade screwdriver, set the trimmer to its midpoint (screwdriver slot perpendicular to the flat side).

Sort all of the resistors by value. The color bands on 1% resistors (which usually have a blue body) can be difficult to read, so you should use a DMM (digital multimeter) to verify their values. Tape them to a piece of paper with the values labeled.

Install the resistors below. Start with R18, which is at the front edge of the board, near the microcontroller, U1 (the only 40-pin IC).

__ R18, 10k, 5% (brn-blk-org) ⇒ __ R17, 10K, 5% (brn-blk-org) __ R5, 120, 5% (brn-red-brn) __ R9, 3.3k, 5% (org-org-red) __ R8, 3.3k, 5% (org-org-red)

__ R7, __ R6, and __ R13, 8.45k, 1% (gray-yel-grn-brn)

__ R16, 10k, 5% (brn-blk-org) __ R11, 680, 5% (blue-gray-brn), 1/2-watt

__ R12, 10k, 5% (brn-blk-org) __ R1, 3.3k, 5% (org-org-red)

Install the 200-ohm, 1-watt resistor (red-blk-brn) at R2, on the bottom of the board. Make sure R2 is flat against the board before soldering.

Install diodes D1 and D2 (1N5711) near connector J3 at the back edge of the board. Make sure the banded end of each diode is oriented toward the right as indicated by its component outline.

Install resistor network RP1 (3.9k). RP1 is located on the right side of the board, near relay K9. The dotted (pin 1) end of RP1 should be oriented to the left. (RP1 is symmetrical and can be reversed, but this orientation will help you visually identify the pin 1 end.)

Install trimmer potentiometers R3 and R4 (100 k, "104"), in the back right corner of the board. The trimmers will sit a small distance above the PC board on the pin shoulders.

Set both trimmer potentiometers to their midpoints.

The subminiature RF choke to be installed in the step has very fragile leads. Do not pull on them. Keep soldering time to a maximum of 2 seconds.

Locate the miniature 15-µH RF choke, RFC1 (brn-grn-blk), which is the same bag as the toroidal cores. Install the choke in the backright corner of the board, near J3.

Check the resistance across RFC1 using the lowest resistance scale of your DMM. This will ensure that the choke was not damaged during soldering. The reading should be under 5 ohms.

Install the ceramic resonator, Z1, near the microcontroller. Z1 looks like a capacitor with three leads.

Near the "KAT100 RF" label in the front-left corner, you’ll find

a short jumper location, identified by a ground symbol ( discarded high-voltage capacitor lead to make a 3/4" (19 mm) U-

shaped wire for this jumper. Mount the jumper on the top side of the board, with the top of the U-shape approx. 1/4" (6 mm) above the board. Solder it from the bottom side.

). Use a

Install diodes D3 and D4 (1N5817), both located along the right edge. Note that the banded ends of these diodes point in opposite directions.

Before handling transistors in the next two steps, touch

an unpainted, grounded metal surface. Electrostatic discharge can cause transistors to become damaged or intermittent.

Using a magnifying glass if necessary, identify the three different types of TO-92 package transistors (small black body, three leads). They will look like one of the two types shown in Figure 2.

ZTX

(a)

Figure 2

Locate the two 2N7000 transistors. Install these at Q2 and Q3 as shown in Figure 2a. Q2 is near the center 2-D fastener on the right edge, and Q3 is near the microcontroller, U1. The flat side of each transistor should be aligned with the flat side of its component outline.

Locate the ZTX789A transistor, which is labeled on its smaller flat side. Install Q1, located near D4. Orient the transistor as shown in Figure 2b.

(b)

789A

Install a similar jumper in the back-right corner, near relay K1.

If you're building a KAT100-1, skip the remaining steps

in this column. Connectors P3, P4, and P6 are only supplied with the KAT100-2 kit.

Install the 40-pin IC socket at U1. Orient the socket so the end

with the open notch is toward the right edge of the board.

Install the 10-pin, dual-row (5x2) male connector at P4, but do not solder yet. Figure 3a shows P4 as viewed from right side of the board. The plastic part of the connector must be on the top side of the board, with the long end of the pins pointed up. The short ends are inserted into the board.

Pin 4

(a)

Solder just one pin of P4. Note: P4's plastic body can melt if too much heat is applied. Limit soldering time to 2 to 3 seconds.

Examine P4 closely. If it is not flat against the board, re-heat the soldered pin while pressing down on the plastic body of the connector.

Solder the remaining pins of P4. Do not trim the leads.

Cut pin 4 of P4 as indicated in Figure 3b, as close as possible to the connector's plastic body.

(b)

Figure 3

C46

In the following steps you'll be installing connectors at

the back edge of the PC board. These connectors must be installed correctly in order for the rear panel to fit onto the board. Figure 13 (page 20) shows how the rear-panel connectors will

appear once installed.

jack must be lined up with the slot-shaped holes in the component outline. If the holes are a tight fit, press firmly until the connector snaps into position, flat against the board. Solder all three pins.

Solder one of the large ground mounting pins first. If J2 then appears to be tilted or twisted, reheat this ground pin while pushing J2 down onto the board. Once it is seated properly, solder the remaining pins.

outline. Do not solder yet.

it is not flat against the board, re-heat the soldered pin while pressing down on the connector. Then solder the remaining pins.

the entire hole).

Install the DC input jack, J1, at the back edge. The 3 leads on the

Install the AUX RF jack, J2 (BNC), in the back-right corner.

Install J3, the 9-pin "D" connector, as indicated by its component

Solder one of the 9 pins (near the center). Examine J3 closely. If

Solder J3's mounting tabs. Use a minimum of solder (do not fill

Locate a 2-pin, high-current male connector (0.156" lead spacing) for use at P3.

Install P3 at its indicated location on the right side of the board, but do not solder yet. Make sure the polarizing tab is oriented as indicated by its component outline.

Press P3 down until it is flat against the board, then solder.

Install P6 (in the back-right corner) in the same manner as P3.

Locate screw terminal E1. If it was supplied with a screw, remove

it. The screw will not be used.

Place E1 in its indicated position, with the threaded hole facing the rear edge of the board. Solder just one pin. CAUTION: This part will get hot; don’t touch it with your finger while soldering.

If necessary, reheat the soldered pin of E1 and adjust it so that all four pins are pressed down on the board as far as they'll go. Then solder all pins.

Locate voltage regulator U8 (78M05 or 7805). Bend the leads of U8 to match its component outline (see Figure 4). Form the leads around the shaft of a small screwdriver to create smooth rather than sharp bends.

se smooth bend

Figure 4

Install U5 (LM358, 8 pins), which is located in the back-right corner. A portion of the part number is printed on the board under the IC ("358"). Do not solder yet.

Bend two opposite corner pins on the bottom side to hold the IC in place. Solder all 8 pins (about 1 to 2 seconds per pin).

U2, 3, and 4 (TPIC6B595) are especially sensitive to

electrostatic discharge. Touch a grounded surface before handling each of them.

Install the remaining ICs. Compare the part number on each IC to the number printed on the board, and make sure that the pin 1 end is oriented correctly.

__ U2, __ U3, and __ U4, TPIC6B595 (or similar number ending in "595")

Insert U8's leads into the proper holes. Secure U8 with a 4-40 x 5/16" (8 mm) machine screw (zinc plated, not black), #4 lock washer, and 4-40 nut.

Solder all three leads. Trim the leads on the bottom side.

Note: The pin 1 end of ICs can be identified by a notch or dimple as shown in Figure 5. This end must be oriented toward the notched end of the component outline.

Notch

Pin 1

Dimple

Pin 1

Figure 5

__ U6, EL5146

Note: U7 is not used.

Remove the relays from their tube. If any of the pins are bent,

straighten them carefully using long-nose pliers.

Place relays at locations K1-K18. The relays can only be installed

one way. Do not solder the relays yet, and do not clip or bend

the relay leads.

Sort the large toroidal cores into two groups: brown (T80-0, .80"

[20 mm]) and red (T94-2, 0.94" [24 mm]).

Using a thin hardcover book to hold the relays in place, flip the

PC board and book over together.

Solder just two diagonally opposite corner pins on each relay.

Turn the board back over. If any relay is not flat against the board, re-heat its corner pins one a time while pressing down on the relay.

Once all relays are properly seated, solder the remaining pins. Do not trim relay leads, which can cause mechanical stress, reducing the life of the relay.

Inductor Winding and Installation

A number of toroidal inductors are used on the RF board.1 The first four inductors to be wound use type T80-0 cores. 80 specifies the outside diameter in hundredths of an inch, in this case 0.80 inches (20.3 mm). The -0 suffix refers to the core type, in this case phenolic. In addition, four T94-2 cores are used (0.94", 24 mm). The

-2 refers to an iron powder core type.

There are also two ferrite toroidal cores used, one of type FT37-43 and one of type FT50-43. In this part number, FT identifies the core as ferrite, and -43 identifies the type of ferrite. The number in the middle again specifies the outside diameter. 37, the smaller size, is

0.37" (9.5mm). 50, the larger size, is 0.50" (12.7mm). Both ferrite cores are dark gray in color and can only be differentiated based on their size.

#20 enamel wire is quite stiff. After winding it tightly

onto the core, you may find that there's a small gap between the wire and the core's flat surfaces. This will not affect performance. If you try to wind the this wire so that it "hugs" the core all the away around, you may have to pull the wire too hard, resulting in hand fatigue.

(23 cm) of #20 red enamel wire. To wind L1, "sew" the long end of the wire through the core. Each pass through the core counts as one turn. Exactly 6 turns are needed, as shown in Figure 6. The enamel insulation will be removed in a later step.

spacing is similar to that shown. If the spacing cannot be matched, it may be because you have one turn too few or too many.

A T80-0 core (brown phenolic) will be used for L1. Cut 9 inches

Figure 6

Place L1 on top of its photo (Figure 6). Adjust the turns until the

Three types of enamel wire are supplied with the kit: #20 red, #26 red, and #26 green. #20 wire is much larger in diameter than #26. Be sure to use only the type called for in the instructions; do not substitute other wire types. Cut wires to the specified lengths to avoid running out of wire.

Pre-wound toroids are available from an Elecraft-approved source; see page 3.

Trim L1's leads to about 3/4" [19 mm] long as shown.

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Elecraft KAT100 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual