Elecraft K3 Owner's Manual

ELECRAFT



K3

HIGH-PERFORMANCE

160 – 6 METER TRANSCEIVER

OWNER’S MANUAL

Revision D10, August 24, 2011

Copyright © 2011, Elecraft, Inc.

All Rights Reserved

2

Contents

A Note to K3 Owners ..................................... 3

Key to Symbols and Text Styles ..................... 3

Quick-Start Guide........................................... 4

Introduction.................................................... 7

K3 Features ............................................................7

Specifications .........................................................8

Customer Service and Support ............................10

Front Panel ................................................... 11

Control Groups.....................................................11

Display (LCD)......................................................12

LEDs.....................................................................13

Front Panel Connectors........................................13

Primary Controls ..................................................13

Multi-Function Controls ......................................14

VFO Tuning Controls ..........................................14

Keypad..................................................................15

Memory Controls .................................................16

Message Record/Play Controls............................16

RIT and XIT Controls..........................................16

Rear Panel .................................................... 17

Connector Groups ................................................17

KIO3 Module .......................................................18

Basic Operation ............................................ 21

Receiver Setup .....................................................23

Reducing Interference and Noise ........................25

Transmitter Setup.................................................26

Voice Modes (SSB, AM, FM).............................28

CW Mode .............................................................30

Data Modes ..........................................................31

Advanced Operating Features....................... 33

Text Decode And Display....................................33

CW-to-DATA.......................................................34

Tuning Aids: CWT and SPOT.............................34

Audio Effects (AFX)............................................35

APF and Dual-Passband CW Filtering................35

Receive Audio Equalization (EQ) .......................35

Transmit Audio Equalization (EQ) .....................35

SPLIT and Cross-Mode Operation......................36

Extended Single Sideband (ESSB)......................36

General-Coverage Receive ..................................36

VFO B Alternate Displays...................................36

Alarm and Auto Power-On..................................36

Using the Sub Receiver........................................37

Receive Antenna In/Out.......................................39

Buffered I.F. Output............................................ 39

Using Transverters .............................................. 39

Scanning .............................................................. 40

Main and Sub Receiver Antenna Routing..... 41

Basic K3 (no KAT3 or KXV3)........................... 41

K3 with KXV3 RF I/O Module.......................... 41

K3 with KAT3 ATU ........................................... 42

K3 with KAT3 and KXV3.................................. 43

Remote Control of the K3 ............................ 44

Options and Accessories .............................. 45

Firmware Upgrades...................................... 45

Configuration............................................... 46

Crystal Filter Setup ............................................. 46

Option Module Enables ...................................... 47

Miscellaneous Setup ........................................... 47

VFO A Knob Friction Adjustment ..................... 48

VFO B Knob Friction Adjustment ..................... 48

Real Time Clock Battery Replacement .............. 48

Calibration Procedures ................................. 49

Synthesizer .......................................................... 49

Wattmeter ............................................................ 49

Transmitter Gain ................................................. 49

Reference Oscillator............................................ 50

Front Panel Temperature Sensor ........................ 51

PA Temperature Sensor ...................................... 51

S-Meter and RF GAIN Control .......................... 51

Menu Functions ........................................... 52

MAIN Menu........................................................ 52

CONFIG Menu.................................................... 53

Troubleshooting ........................................... 64

Parameter Initialization....................................... 66

Module Troubleshooting..................................... 67

Theory Of Operation .................................... 71

RF BOARD ......................................................... 71

KAT3 (ATU) and KANT3 ................................. 73

KIO3 (AF/Digital I/O) ........................................ 73

Front Panel and DSP ........................................... 73

KREF3 (Ref./2nd LO).......................................... 74

KSYN3 (Synthesizer) ......................................... 75

Firmware.............................................................. 75

K3 Block Diagram .............................................. 76

Appendix A: Crystal Filter Installation......... 77

Index............................................................ 81

3

A Note to K3 Owners

On behalf of our entire design team, we’d like to thank you for choosing the Elecraft K3 transceiver.

The K3—like its predecessor, the K2—reflects our desire to go beyond what other high-performance
transceivers have offered. It isn’t just a home-station rig; at about 8 to 9 pounds, it can accompany you
wherever you go, whether it’s out to your back porch or halfway around the world. And it’s the only
rig in its class that you can build yourself. Above all, we want the K3 to be ready for any operating
situation you encounter, and to be more enjoyable to use than any transceiver you’ve ever owned.

In addition to this manual, you’ll find much more information on the K3 on our web site, including
operating tips, answers to frequently asked questions, and information on firmware upgrades and
accessories.

73,

Wayne, N6KR
Eric, WA6HHQ

Key to Symbols and Text Styles

Important – read carefully

Operating tip

LS B

. .

LCD icon or characters

LED

Enter keypad function

XM I T

T U N E

Tap switch function (labeled on a switch)

Hold switch function (labeled below a switch; hold for 1/2 sec. to activate)

SQL

P WR

MO N

Rotary control without integral switch

Tap switch function of rotary control (labeled above a knob)

Hold switch function of rotary control (labeled below a knob; hold for 1/2 sec.)

MAIN:VOX GN

Typical MAIN menu entry

CONFIG:KAT3

Typical CONFIG menu entry

4

Quick-Start Guide

To get started using your K3 right away, please read this page and the two that follow, trying each of the
controls. The text uses braces to refer to numbered elements in the front- and rear-panel illustrations below. For
example, {1} refers to 1, the mic jack. Later sections provide greater detail on all aspects of K3 operation.

The first thing you need to know about the K3 is that most switches have two functions. Tap (press

briefly) to activate the function labeled on a switch. Hold to activate the function labeled below the switch. In

the text, tap functions are shown like this: M EN U . An example of a hold function is CO N FI G . Additional
typographical conventions are shown on the previous page.

Try tapping M E NU {8}. This brings up the MA IN menu. Rotating VFO B {19} selects menu entries, while
rotating VFO A {22} changes their parameters. Tap M E NU again to exit the menu.

5

Connections

• Connect a power supply to the DC input jack {26} (see Specifications, pg. 8).

• On the K3/100, a circuit breaker is provided on the fan panel for the 100-W stage {38}.

• You can power an accessory device from the switched DC output jack {39} (0.5 A max).

• Connect an antenna to ANT1 {29}. With an ATU (pg. 22), you can also use ANT2 {28}.

AUX RF {27} is for the sub receiver; see pg. 17. ANT3 {30} is used with the internal 2-m
module (K144XV). With a KXV3, you can connect an RX antenna to RX ANT IN {34}.

The Basics

• Press P OWE R {5} to turn on the K3. If there are any error indications, refer to pg. 68.

• T AP and HO L D Functions: Tapping briefly activates the function labeled on a switch.

Holding for about 1/2 second activates the function labeled below a switch.

• Tap either end of B AN D {7} to select a band, and tap M OD E {6} to select the mode. Set

the AF gain using AF {2}. Set RF to max. SUB controls are discussed on pg. 37.

• The large knob {22} controls VFO A (upper display, {10}). The medium knob {19}

controls VFO B (lower display, {11}). VFO A is main RX/TX except in SPLIT (pg. 36).

• CM P / PWR is one of four multifunction controls {24}. Each has two primary

functions, indicated by green LEDs. The knob has a built-in switch; tap it to select either

CM P (compression level) or PW R (power output). Hold the knob in to access its

secondary function, MON itor level. Tap again to restore the primary function.

Filter

Controls

• Rotate the SHIFT / LOCUT and HICUT / WIDTH controls {23} to adjust the filter

passband. Crystal filters FL1 -FL5 are automatically selected as you change the
bandwidth. Tap either knob to alternate between shift/width and hicut/locut.

• Hold SHIFT / LOCUT to N OR Malize the bandwidth (e.g., 400 Hz CW, 2.8 kHz SSB).

• Hold HICUT / WIDTH to alternate between two filter setups, I and II (per-mode).

• Tap X FIL {13} to select crystal filters manually; this also removes any passband shift.

Voice Modes

{1}

• Hold M E TE R {8} to see CMP / ALC levels. While talking, set MIC {25} for 4-7 bars

of ALC, and CMP for the desired compression. Then return to SW R / PW R (pg. 28).

• Optional: Hold T E S T {6} for TX TEST mode; allows off-air TX adjustments (pg. 13).

• Hold CMP / PWR {24} to set speech MO Nitor level; tap to return to C M P / PW R .

• Hold VO X {7} to select PTT or VO X . Hold SPEED / MIC to set VOX D EL AY.

• Details: VOX, pg. 29; TX EQ, pg. 35; MIC SEL, pg. 52; SSB/AM/FM, pg. 28.

CW Mode

{36}

• SPEED {25} sets the CW keyer speed. Hold this knob to set semi-break-in DEL AY.

Hold Q S K {7} to select full Q S K (pg. 30.). Hold V O X {7} to select hit-the-key CW.

• Hold P I T CH {18} to set sidetone pitch. Hold CMP / PWR to set sidetone M ON level.

• Tap C WT {18} for tuning aid {9} (pg. 34). With CW T on, S PO T auto-spots (pg. 30).

• To select CW text decode/display mode, hold T E XT DEC {18}; rotate VFO B (pg. 30).

• CW keying is converted to DATA in FSK D and PSK D modes (below and pg. 34).

• Hold D U AL PB {13} to turn on audio peaking (APF) or dual-passband filtering (pg. 30).

Data Modes

{31}

• Tap M OD E {6} until you see the DA T A icon turn on (see Data Modes, pg. 31).

• Hold D A TA MD {18}. Use VFO B to select from: DA T A A (PSK31 & other

soundcard-based modes), AF S K A (soundcard-based RTTY), FS K D (RTTY via data
input or keyer), or PSK D (PSK via data input or keyer). VFO A selects data baud rate
for internal encoder/decoder, if applicable. DU A L P B turns on RTTY filter (DTF, pg. 32).

• Hold P I T CH {18} to select mark tone and shift (for encoder/decoder and RTTY filter).

• Hold TE X T D EC {18} to set up text decode. C W T shows tuning aid (pg. 34).

6

VFOs
and RIT/XIT

• R AT E {21} selects 10 or 50 Hz VFO/RIT tuning. See VFO menu entries, pg. 53.

• F IN E {21} selects 1-Hz steps. CO A RS E selects large steps (MAIN menu, VFO CRS).

• Tap F REQ EN T {21} to enter frequency in MHz using numeric keypad & decimal point.

Tap return ( ) to complete the entry, or tap F R EQ E NT again to cancel. (Pg. 15.)

• Hold SC A N to start/stop scanning. S CA N must be preceded by a memory recall (pg. 40).

• The R IT and XI T offset knob {17} has LEDs that show -/0/+ offset (pg.16). Tap C LR

{16} to zero the offset. Hold C LR for > 2 sec. to add the offset to VFO A, then zero it.

Transmit,
ATU, and
Antenna
Controls

• The TX LED {4} indicates that the K3 is in transmit mode. The ∆ f LED turns on if the

RX and TX frequencies are unequal (S P LI T , R I T /X I T , cross-mode, etc.). (Pg. 13.)

• X MIT {8} is equivalent to PTT {35}. TUN E puts out full CW power in any mode.

• A TU TU N E {8} initiates antenna matching (pg. 22). AT U enables or bypasss the ATU.

• A NT selects AN T 1 or A N T2 . R X AN T selects main or RX antenna (KXV3).

NB, NR,
and Notch

• Tap N B {12} to enable DSP and I.F. noise blanking. Hold L E VE L to set DSP NB level

(VFO A) and I.F. NB level (VFO B). Fully CCW is OFF in both cases. (Pg. 25.)

• Tap N R {12} to turn on noise reduction (saved per-mode). Hold A D J to tailor noise

reduction for the present band conditions (pg. 25).

• Tap N TC H {12} once to select auto-notch (NTC H icon), and a second time to select

manual notch (adds icon). Hold MA N to adjust manual notch frequency. (Pg. 25.)

SPLIT,
BSET,
and SUB

• Hold S P LI T {13} to enter split mode (RX on VFO A, TX on VFO B). If VFOs A and B

are on different frequencies in SPLIT mode, the Delta-F LED (∆ f ) will turn on (pg. 13).

• Hold B S ET {13} to adjust VFO B / sub RX settings independently of VFO A (pg. 37).

• Tap S UB {20} to turn on the sub receiver (pg. 37). VFO B controls its frequency.

• Hold S UB {20} to link the two VFOs (VFO A is then the master). A 2-second hold of

SU B engages diversity mode (pg. 38). SPLIT operation is possible in diversity mode.

Memories,
Messages, and
DVR

• To store a frequency memory, tap V M {14}, then: tap M 1 -M 4 {15} to save a per-band

quick memory; or tap 0 -9 to save a general-purpose quick memory; or rotate VFO A to
select from memories 0-99, then tap V M again to save. Tap M V to recall. (Pg. 16.)

• R EC and M 1 -M 4 {15} are also used to record & play voice/CW/DATA messages. The

KDVR3 option is required for voice messages and A F R E C / AF PL A Y (pg. 29).

Menus and
Switch Macros

• M ENU & CON FIG {8} access the MAIN and CONFIG menus. VFO B selects entries;

VFO A changes parameters. In general, CONFIG menu entries are used less often.

• Tapping D IS P {8} within menus shows information about each entry on VFO B (pg 52).

• Menu entries can be assigned to programmable switches PF 1 , PF 2 {16} and M 1 -M 4 {15}

(pg 52). These switches can also execute often-used macros like “SPLIT, A>B, move VFO
B up 5,” with a single tap or hold. See the K3 Programmer’s Reference for examples.

Other
Features

• RX and TX EQ (MAIN menu) provide 8 bands of receive/transmit equalization (pg. 35).

• Tap A FX {18} to enable the selected audio effect (see CONFIG:AFX MD, pg. 52).

• Tap D IS P {8} and use VFO B to show time, supply voltage, etc. on VFO B (pg. 36).

• The ALARM function (MAIN:ALARM menu entry) can be used to remind you about a

contest, net, or QSO schedule, and can even turn the K3 on at alarm time (pg. 36).

• The KIO3 module provides a rich set of AF {33} and digital {32} I/O (pg. 17).

7

Introduction

This comprehensive manual covers all the features
and capabilities of the Elecraft K3 transceiver. We
recommend that you begin with the Quick-Start

Guide (pg. 4). The Front Panel (pg. 11) and Rear
Panel (pg. 17) sections are for general reference.
Basic Operation (pg. 21) and Advanced
Operation (pg. 33) fill in the details.

Anytime you add new filters or options, refer to

Configuration (pg. 46).

K3 Features

The K3 offers a number of advanced features to
enhance performance and versatility:

Receiver

• Up to five crystal roofing filters with

bandwidths as narrow as 200 Hz (pg. 23)

• High-performance, fully independent sub

receiver, also with up to five crystal filters,
allows true diversity receive with two
antennas (pg. 37)

• Variable-bandwidth crystal filters that track

DSP filter settings

• Narrow ham-band front-end filters, plus

wider band-pass filters for general-coverage
receive (pg. 45)

DSP

• 32-bit I.F. DSP for advanced signal

processing, including full stereo and other
binaural effects (pg. 35)

• Passband tuning and programmable

DSP/crystal filter presets (pg. 14)

• 8-band transmit and receive EQ (graphic

equalization) (pg. 35)

• Versatile digital voice recorder (DVR) for

incoming/outgoing audio streams (pg. 29)

CW and Digital Modes

• Built-in digital-mode demodulation with

text displayed on the K3’s LCD (CW,
RTTY, PSK31) (pg. 33)

• APF (audio peaking filter) for digging out

weak signals in CW mode (pg. 30)

• Internal CW-to-RTTY or CW-to-PSK31

encoding for casual digital-mode QSOs
without a computer (pg. 34)

• CW decoded and displayed as you send –

great for improving CW skills (pg. 33)

• Automatic CW/data signal spotting and

manual fine-tuning display (pg. 30)

User Interface

• Dual VFOs with independent modes,

bands, and filter settings (pg. 14)

• 100 memories with alphanumeric labels,

plus 4 quick-memories per band (pg. 16)

• Dedicated message play controls for use in

CW, data, and voice modes (pg. 30)

• Real-time clock/calendar with alarm and

automatic power-on (pg. 36)

• Utility displays show voltage, current drain,

RIT/XIT offset, front panel temperature,
PA heatsink temperature, etc. (pg. 36)

• Built-in help menu help text (pg. 21)

• Programmable switch “macros” to

automate often-used operations (pg. 44)

• Custom “sign-on banner” can be displayed

on power-up (via the K3 Utility program)

Connectivity

• Enhanced remote control (pg. 44)

• Firmware upgrades via the Internet (pg. 45)

• Isolated PC audio input/outputs (pg. 17)

• Front and rear mic and headphone jacks

• Full stereo audio with two speaker outputs

Options and Accessories (pg. 45)

• ATU, sub receiver, digital voice recorder,

100-W PA, 2-meter module, external
reference lock, and other internal options

• KPA500 amplifier, P3 Panadapter, PR6 six-

meter preamp and other accessories

8

Specifications

Some specifications apply only if the corresponding option modules are installed (see Options, pg. 45).

GENERAL

Frequency Range

Main and Sub Receivers, 490 kHz - 30 MHz and 44-54 MHz. Transmitter: Amateur
bands between 1.8 and 54 MHz (varies by country). 144-148 MHz with K144XV
option.

MARS coverage on request (excluding transmit from 7.550-8.999 MHz at 13 W and
higher, and 7.650-8.999 MHz at 12 W or lower).

Tuning Step Sizes

1, 10, 20, and 50 Hz fine steps; user-configurable coarse tuning steps (per-mode).
Direct keypad frequency entry in either MHz or kHz.

Memories

100 general purpose, plus 4 scratch-pad memories per band

Frequency Stability

+/- 5 ppm (0-50 C) TCXO standard; +/- 1 ppm TCXO opt. (+/- 0.5 PPM typ., 0-50 C).
K3EXREF option locks TCXO to an external 10-MHz reference (+/- 1 to 2 Hz typ.).

Antenna Jacks

50 ohms nominal. One SO-239 supplied (2nd SO-239 jack supplied with KAT3 ATU).
BNC jacks for RX antenna in/out and transverter in/out (KXV3 Option).

Modes

USB, LSB, AM, FM, CW, DATA (FSK D [direct], AFSK A [Audio], PSK D [Direct]
and DATA A [Audio]; PSK). Built in PSK, RTTY, and CW text decode/display.

VFOs

Dual VFOs (A and B) with separate weighted tuning knobs

Remote Control Port

EIA-232 standard DE-9F; USB adapter option. Full control of all radio functions.

Audio I/O

Line-level isolated TX/RX audio interface (stereo outputs); front (1/4”) and rear (1/8”)
stereo headphone jacks; stereo speaker jack.

Transverter Interface

Transmit, 0 dBm typ.; BNC in/out connectors on KXV3 option module. KXV3A
(updated KXV3) includes connectors for K144XV internal 2-meter module.

Buffered IF output

BNC connector (KXV3 Option); see pg. 39 for interface recommendations.

Other I/O

Key/Keyer/Computer, Paddle, PTT In, and KEY Out. Band information output via
binary interface and AUXBUS on ACC connector.

Real-Time Clock/Calendar

Accuracy: Approx. +/- 20 ppm (+/- 2 seconds/day). U.S. and E.U. date formats.
Battery: 3 V coin cell (see pg. 48 for replacement instructions).

Supply Voltage
and Current

13.8 V nominal (11 V min, 15 V max). 17-22 A typical in TX for K3/100, 3-4 A
typical in TX for K3/10. 0.9A typical RX (less sub receiver). When using reduced
supply voltage (< 12 V), power output should be reduced (e.g. 70 W at 11 V).
Recommended supply: 13.8VDC @ 25A, continuous duty for K3/100; 13.8VDC @
6A for K3/10. For best results, use the supplied 5 foot (1.53 m) power cable. When a
battery is used, both sides of the battery cable should be protected by fast-blow fuses.

Accessory DC output

Switched, 0.5 A max; 13 V no-load, 12 V max load (@ Vsupply = 13.8 V)

Weight (K3/100)

Approx. 8.5 lbs. (3.8 kg). With KRX3 sub receiver option, 9.5 lbs. (4.3 kg).

Size

Enclosure only, 4.0 x 10.7 x 10.0 in., HWD (10.2 x 27.2 x 25.4 cm). With projections,

4.4 x 11.1 x 11.8 in. (11.2 x 28.2 x 30.0 cm).

9

RECEIVER (Main and Sub)*

Sensitivity (MDS)

-136 to -138 dBm (typ.), preamp on, 500 Hz bandwidth. 6 m MDS with PR6 option:

-143 to -144 dBm (typ.). Reduced sensitivity near 8.2 MHz (first I.F.) and from 44-

49.5 MHz. Sensitivity decreases gradually below 1.8 MHz due to intentional high­pass response at the T-R switch. (Use RX ANT input or sub receiver’s AUX input to
avoid the high-pass filter loss.) Note: KBPF3 option required for full general
coverage (including 0.49 to 1.7 MHz).

Dynamic Range

IMD3 > 100 dB, Blocking 140 dB, typical (at 5, 10, and 20 kHz spacing)

Image and I.F. Rejection

> 70 dB

Audio Output

2.5 W per channel into 4 ohms; typ. 10% THD @ 1 kHz, 2 W

S-Meter

Nom. S9 = 50 µV, preamp on; user-adjustable

Noise Blanker

Adjustable, multi-threshold/multi-width hardware blanker plus DSP blanker

Receive AF graphic EQ

+/- 16 dB/octave, 8 bands

Filter Controls

IF Shift/Width & Lo/High Cut with automatic crystal filter selection

* Receive specifications are guaranteed only within ham bands. Dynamic range measurements based on 400-Hz, 8-pole
filter. Other available filters have very similar performance; see www.elecraft.com for full list.

TRANSMITTER *

Output Power

K3/100: 0.1 W –100 W typ. Suggested max from 51-52 MHz, 85 W; 52-54, 70 W.
K3/10 (or K3/100 with PA bypassed): 0.1 W –12 W, HF-10 m; 8 W max on 6 m.
XVTR OUT (KXV3 option): -10 to +1.8 dBm. K144XV: ~10 W, 144-148 MHz.

Note: Output can be set up to 110 W. However, IMD and spurious products are
specified at 100 W, the recommended max. If a KAT3 ATU is installed, actual
output will be slightly lower (typ. loss < 0.5 dB below 28 MHz, < 0.8 dB above).

Duty Cycle

CW and SSB modes, 100% 10-min. 100W key-down at 25 C ambient

True RF Speech Processor

Adjustable compression

Transmit AF graphic EQ

+/- 16 dB/octave, 8 bands

SSB TX Bandwidth

4 kHz max (> 2.8 kHz requires 6 kHz AM filter)

SSB TX Monitor

Post-DSP filtering/processing

VOX

DSP-controlled, adjustable threshold, delay, and anti-VOX

Full and Semi CW Break-In

Adjustable delay; diode T/R Switching

SSB Carrier Suppression

> 50 dB

Harmonic / Spurious Outputs

> 50 dB below carrier @ 100W (> 60 dB on 6 meters)

CW Offset/Sidetone

300-800 Hz, adjustable (filter center frequency tracks sidetone pitch)

Mic Connector

Front panel, 8 pin; rear panel 3.5 mm. Switchable DC bias (MAIN:MIC SEL)

* Transmit specifications are guaranteed only within ham bands.

10

Customer Service and Support

Technical Assistance

You can send e-mail to [e-mail] and we will respond quickly – typically the same day
Monday through Friday. If you need replacement parts, send an e-mail to [e-mail]. Telephone
assistance is available from 9 A.M. to 5 P.M. Pacific time (weekdays only) at 831-763-4211. Please use e-mail
rather than calling when possible since this gives us a written record of the details of your problem and allows us
to handle a larger number of requests each day.

Repair / Alignment Service

If necessary, you may return your Elecraft product to us for repair or alignment. (Note: We offer unlimited email
and phone support, so please try that route first as we can usually help you find the problem quickly.)

IMPORTANT: You must contact Elecraft before mailing your product to obtain authorization for the
return, what address to ship it to and current information on repair fees and turn around times. (Frequently we
can determine the cause of your problem and save you the trouble of shipping it back to us.) Our repair location
is different from our factory location in Aptos. We will give you the address to ship your kit to at the time of
repair authorization. Packages shipped to Aptos without authorization will incur an additional shipping charge

for reshipment from Aptos to our repair depot.

Elecraft 1-Year Limited Warranty

This warranty is effective as of the date of first consumer purchase (or if shipped from the factory, the date the
product is shipped to the customer). It covers both our kits and fully assembled products. For kits, before requesting
warranty service, you should fully complete the assembly, carefully following all instructions in the manual.

Who is covered: This warranty covers the original owner of the Elecraft product as disclosed to Elecraft at the time
of order. Elecraft products transferred by the purchaser to a third party, either by sale, gift, or other method, who is
not disclosed to Elecraft at the time of original order, are not covered by this warranty. If the Elecraft product is being
bought indirectly for a third party, the third party’s name and address must be provided at time of order to ensure
warranty coverage.

What is covered: During the first year after date of purchase, Elecraft will replace defective or missing parts free of
charge (post-paid). We will also correct any malfunction to kits or assembled units caused by defective parts and
materials. Purchaser pays inbound shipping to us for warranty repair; we pay shipping to return the repaired
equipment to you by UPS ground service or equivalent to the continental USA and Canada. For Alaska, Hawaii, and
other destinations outside the U.S. and Canada, actual return shipping cost is paid by the owner.

What is not covered: This warranty does not cover correction of kit assembly errors. It also does not cover
misalignment; repair of damage caused by misuse, negligence, or builder modifications; or any performance
malfunctions involving non-Elecraft accessory equipment. The use of acid-core solder, water-soluble flux solder, or
any corrosive or conductive flux or solvent will void this warranty in its entirety. Also not covered is reimbursement
for loss of use, inconvenience, customer assembly or alignment time, or cost of unauthorized service.

Limitation of incidental or consequential damages: This warranty does not extend to non-Elecraft equipment or
components used in conjunction with our products. Any such repair or replacement is the responsibility of the
customer. Elecraft will not be liable for any special, indirect, incidental or consequential damages, including but not
limited to any loss of business or profits.

11

Front Panel

This reference section describes all front panel controls, the liquid crystal display (LCD), LEDs, and connectors.
Operating instructions are covered in later sections.

Control Groups

Primary Controls (pg 13): These controls

provide basic transceiver setup, including power
on/off, band, operating mode, AF and RF gain and
squelch, ATU and transmit controls, display modes,
and menus.

Display (pg 12): The LCD shows signal levels,
VFO A and B frequencies, filter bandwidth,
operating mode, and the status of many controls.
The VFO B display is alphanumeric, so it can show
decoded text from digital modes (CW, RTTY,
PSK31), as well as menus, time and date, help
messages, etc.

Multi-Function Controls (pg. 14): The upper two
knobs set up receiver DSP filtering. The lower two
control transmit parameters, including keyer speed,
mic gain, speech compression, and power output
level. LEDs above each knob show which function
is active; tapping the knob alternates between them.
Pressing and holding these knobs (1/2 second or
longer) provides access to secondary functions.

Keypad (pg. 15): This group of switches is
numbered for use during memory store/recall and
direct frequency entry, but each switch also has
normal tap and hold functions. The upper row of
switches are VFO controls. The remaining rows
control receive-mode and miscellaneous functions,
such as noise reduction and text decode/display.

Memories (pg. 16): These switches control
frequency memory store/recall, message
record/play, and audio record/playback (with the
DVR). M 1 -M 4 can also be used as up to eight
tap/hold programmable function switches.

VFOs (pg. 14): The large knob controls VFO A;
the smaller knob controls VFO B. The four
switches between the VFO knobs select tuning rates
and control related functions.

RIT/XIT (pg. 16): Three switches control RIT and
XIT on/off and clear (offset zero). The knob below
the R IT /X I T switches selects the offset.

12

Display (LCD)

Multi-character displays: The 7-segment display

(upper) shows the VFO A frequency. The 13­segment display (lower) shows VFO B or text.

Bar graph, receive mode: The bar graph normally
acts as an S-meter. If C WT is turned on, the right
half of the S-meter becomes a tuning aid (pg. 34).

Bar graph, transmit mode: The bar graph
normally shows SWR and RF power output. The

RF scale will be either 5 and 10 (low power) or 50

and 10 0 (high power). In voice and data modes,
transmit scales can be changed to compression
(CM P ) and ALC using ME T ER .

VFO Icons: The TX icon indicates which VFO is
selected for transmit. In TX TEST mode, or when
TX is inhibited externally, TX flashes (see T ES T).

Shows that VFO A or B is locked (see

L O C K

).

TX

A

VFO A is the transmit VFO

TX

B

VFO B is the transmit VFO; see

Filter Graphic: This shows the approx. bandwidth
and position of the receiver’s I.F. passband. See

Filter Passband Controls, pg. 23.

Filter Icons:

NT C H Notch filtering on (N T CH , pg. 25)

Manual notch (MA N , pg. 25)

I / II Shows selected preset (I / II, pg. 14)

XFIL Crystal filter selection (FL1 -FL5 )

Mode Icons:

Basic modes (LSB / USB , CW , DA TA , A M, or

FM) are selected by tapping either end (Up/Down)

of M ODE . Alternate modes (CW R E V , DA T A

RE V , AM - S, F M +/- ) are selected by holding

AL T . LS B and US B are alternates of each other.

+ icon on in SSB modes indicates ESSB (pg. 36).

T indicates FM/tone, CW/DATA text decode, or

AM-Sync auto-tracking.

Other Icons:

CW T CW/data tuning aid on (C WT , pg. 34)

DVR in use (A F R E C / A F P LA Y , pg. 16)

VOX VOX enabled (V O X , pg. 13)

QSK Full break-in CW enabled (Q S K , pg. 30)

NB Noise blanker on (N B , pg. 15)

NR Noise reduction on (N R , pg. 15)

AN T Antenna 1 or 2 (A N T , pg. 13)

RX RX antenna in use (R X A NT , pg. 13)

AT T Attenuator on (AT T , pg. 15)

PR E Preamp on (P RE , pg. 15)

AT U ATU enabled (AT U , pg. 13)

RI T RIT on (R I T , pg. 16)

XIT XIT on (X IT , pg. 16)

SU B Sub receiver on (S UB , pg. 37)

SPL T Split mode in effect (SP L IT , pg. 36)

SPLIT

13

LEDs

TX [Red] Turns on in transmit mode.

∆ F [Yellow] The Delta-F LED turns on if

transmit and receive frequencies or modes are
different due to the use of SPLIT, RIT, or XIT.

[Green] Eight LEDs show which functions are

in effect for the Multifunction Controls (pg. 14).

(- )

( + ) RIT/XIT OFFSET If the

offset control is centered, or you tap C LR , the

green LED turns on (offset = 0). Otherwise, the
yellow (-) or (+) LED will be on, indicating the

direction of the offset. See R IT , X I T , and C L R .

Front Panel Connectors

PHONES You can use either mono or stereo

headphones at either the front- or rear-panel
headphone jack. Also see A FX (pg. 35).

MIC An Elecraft MH2, MD2, Proset-K2, or other
compatible mic can be used (see pinout below). To
select the front- or rear-panel mic, and to turn bias
on/off, use the MAIN:MIC SEL menu entry.

Bias must be turned on for electret mics (e.g. MH2,
MD2, Proset). It must be off for dynamic mics (e.g.
Heil mics using HC4 or HC5 elements).

Mic jack, viewed from front of K3

1 Mic audio, low-Z (~600 ohms)
2 PTT
3 DOWN button *
4 UP button *
5 FUNCTION button *
6 8V (10 mA max)
7, 8 Ground

* See CONFIG:MIC BTN menu entry.

FP ACC This connector (RJ-45, 6 pins) is located

on the bottom of the transceiver, near the VFO B
knob. It is used with accessory devices.

Primary Controls

BA N D Tap left/right end to move among ham

bands. CONFIG:BND MAP disables bands. For
“quick” band switching, see CONFIG:MEM 0-9.

VO X Selects voice-operated or CW keying-

operated transmit (VO X icon on), or PTT (VO X
icon off). Also see

DE L AY (pg. 30) and CW

VOX auto-off control (CONFIG:CW WGHT).

QS K Selects either full break-in (QS K icon on) or

semi break-in keying, if VOX is selected in CW
mode. Also see

DE L AY (pg.30).

MO D E Tap the left or right end of this switch to

select the operating mode. When DA T A is selected,
the DA T A M D switch is used to specify DATA-A,
AFSK A, FSK D, or PSK D (pg. 31).

AL T In LS B mode, switches to US B (and vice-

versa). Also selects alternate modes, including:

CW RE V , DA TA R EV, and A M -S (pg. 29). In
FM mode, selects + /- or simplex (pg. 29).

T E S T Selects TX TEST (T X LCD icon flashing);

allows key/mic test without actually transmitting.

PO W E R Turns the K3 on or off. Note: To ensure

correct save of operating parameters, turn the
K3 off before turning the power supply off.

ME N U Displays MAIN menu (pg. 21).

CO N FI G Displays the CONFIG menu (pg. 21).

XM I T Manually-operated transmit. Places the K3

into transmit mode (same as PTT, pg. 26).

T U N E Puts out a carrier at the present power level.

Also TUNE Power Level (pg. 27).

RX AN T Enables the receive antenna (pg. 22). If

the sub RX is on, holding R X A NT alternates
between the sub’s MA I N / A U X antennas (pg. 37).

DI S P Shows an alternate display on VFO B, such

as time, date, voltage, etc. (pg. 36).

ME T ER Selects voice transmit bar graph modes:

SW R and RF, or C MP and ALC (pg. 28).

AT U T U NE Matches the antenna (transmitting at

up to 10 W) using the KAT3 ATU (pg. 22).

AT U Puts the ATU into normal mode (AT U icon

on) or bypass mode (pg. 22).

AN T Selects AN T 1 or 2 . In BSET mode with the

sub receiver on, selects MA I N or A U X antenna for
the sub receiver (pg. 37).

14

Dual-Concentric Potentiometers

AF — SUB AF gain controls for main
receiver (inner, or smaller knob) and sub receiver
(outer ring, or larger knob).

RF / S Q L — SUB RF gain (and/or squelch)
controls for main and sub receiver.

Two menu entries are provided to control squelch
directly: CONFIG:SQ MAIN, and SQ SUB. They
can also be used to reconfigure the RF gain controls
as squelch for either receiver, and to select FM-only
or all-mode squelch. See Config Menu (pg. 53).

Multi-Function Controls

The upper two multi-function controls set up
receiver filtering. The lower two controls adjust
transmit settings. Each control has two primary
functions (white labels) and a secondary function
(yellow). Tap a control knob to alternate between
its primary functions, indicated by two LEDs. Hold
a knob (~1/2 second or longer) to select its
secondary function.

Filter Controls

The primary functions of the filter controls are:

S HIF T Shift passband either direction

L O C UT Adjust low-frequency response

H I CU T Adjust high-frequency response

W ID TH Adjust width of the passband

As these settings change, so does the filter graphic.
Crystal filters are selected automatically (or
manually using X FI L , pg. 15). Also see Filter
Passband Controls (pg. 23).

The secondary functions of these controls are:

NO R M Normalize passband

Normalizing the passband sets the bandwidth to a
fixed, per-mode value (e.g. 400 Hz in CW mode)
and centers the passband. (Also see user-defined
normal settings, NO R M1 /2, pg. 24.)

I/ I I Select preset I or II (per mode)

Presets I and II each hold a continuously-updated
DSP/crystal filter setup (pg. 24).

Transmit Controls

The primary functions of the transmit controls are:

S PEE D Keyer speed in WPM, 8-50 (8-100

if CONFIG:CW QRQ is ON )

M IC Mic gain
C MP Speech compression level
P WR RF output power in watts (pg. 26)

The present transmit mode determines which
primary functions normally apply; for example, in
CW mode, the S P EE D / M I C control defaults to

SP E E D . You can always tap a knob to override

the present selection.

The secondary functions of these controls are:

DE L AY VOX delay (voice/data) or CW semi-

break-in delay, in seconds

MO N Voice or data monitor level or

CW/data sidetone level

You can optionally LOCK the MIC, CMP, and

PWR control settings; see CONFIG:PWR SET.

VFO Tuning Controls

VFO A controls the upper frequency display. This
is normally the RX and TX frequency. In SPLIT
mode, VFO B controls the transmit frequency (pg.

36). VFO B also controls the sub receiver (pg. 37).

The controls to the right of VFO A include:

FR E Q E N T Direct frequency entry (pg. 15)

SC A N Start or stop scanning (pg. 40)

F I N E Select 1 Hz tuning for both VFOs

and RIT/XIT offset

CO A RS E Select coarse tuning rate (pg. 22)

RA T E Select one of two normal tuning rates

(10/50 or 10/20 Hz; pg. 22)

L O C K Lock VFO A (use B S E T to lock B)

SU B Tap to turn sub RX on/off (pg. 37).

Hold to link/unlink VFO A and B on
the present band (pg. 37). A long hold
(2 seconds or longer) enters diversity
mode (pg. 38).

VFO A can optionally be coarse-tuned using

the RIT/XIT offset control if both RI T and XI T are
off . See CONFIG:VFO OFS.

15

Direct Frequency Entry

To jump to any frequency within the tuning range
of the K3, tap F RE Q E N T , then enter 1 to 3 MHz
digits, a decimal point, and 0 to 3 kHz digits.
Follow this with Enter ( . . ) to accept or

F R E Q E NT to cancel. The decimal point is

optional if no kHz digits are entered, making it very
easy to get to the low end of most ham bands.

Examples:

1.825 MHz: F RE Q E N T 1 . 8 2 5 . . .

1.000 MHz: F RE Q E N T 1 .

50.100 MHz: F REQ EN T 5 0 . 1 .

If four or more digits are entered without a

decimal point, a value in kHz is assumed.

Keypad

Keypad switches have the tap and hold functions
listed below. They are also used for selecting quick
memories 0-9, and for direct frequency entry.

VFO Controls (Upper row)

The upper row of numeric keypad switches is used
to set up VFOs A and B. Their functions are:

A / B Exchange VFO A and B contents

BS E T Set up VFO B and sub RX (see below)

RE V Exchange VFO A and B temporarily

(repeater RX/TX swap in FM-RPT)

A B Copy VFO A frequency to VFO B;

tapping twice copies all other settings
(also see CONFIG:VFO B->A)

SP L IT Enable SPLIT receive/transmit

If cross-mode operation is not allowed for the
present VFO A and B modes, you’ll see SPL N /A
if you try to enable SPLIT. If cross-mode operation
is allowed, the mode icon for VFO B will flash as a
warning. Tap any switch to cancel the flash.

Holding B S ET allows VFO B (and the sub
receiver, if on) to be set up directly (pg. 37). As
long as BS E T is displayed, all VFO-related
controls and display elements apply to VFO B. An
alternative is to exchange VFOs with A / B , set up
VFO A, then exchange them again.

Receiver Control & Misc. (Lower Rows)

Receiver control functions normally apply to
VFO A/main receiver. If BS E T is in effect, they
apply to VFO B (and the sub receiver if turned on).

PR E Preamp on/off (6 m: see PR6, pg. 45)

AT T Attenuator on/off

AG C AGC slow/fast (also see CONFIG:

AGC DCY, AGC HLD, and other
AGC menu entries)

OF F AGC off/on (when off, an AF limiter

is available; see CONFIG:AF LIM)

XF I L Select next available crystal filter

(see CONFIG:FLx ON)

DU A L P B CW: APF or Dual-passband filtering

(see CONFIG:DUAL PB);
RTTY: dual-tone filtering (pg. 30)

NB Noise blanker on/off (pg. 25)

L E V EL Noise blanker levels (pg. 25); use

VFO A knob to setup DSP blanker,
and VFO B to setup I.F. blanker

NR Noise reduction on/off (pg. 25)

AD J Noise reduction parameter adjust; use

VFO B knob (pg. 25)

NT C H Notch filter auto/manual/off (pg. 25)

MA N Manual notch frequency (pg. 25); use

VFO B knob

SP O T Spot tone on/off (manual), or auto-

spot (if CWT is on; pg. 34)

PI T CH CW sidetone PIT CH, PSK center

pitch, FSK / AFSK MARK tone and
shift (pg. 31), or FM tone setup (pg.

29)

CW T CW/data tuning aid on/off (pg. 34);

turn on to use auto-spot

T E X T DE C Text decode, CW or DATA (pg. 33);

use VFO B knob to select mode

AF X Audio effects on/off (pg. 35); use

CONFIG:AFX MD to set mode

DA T A M D DATA mode selection (pg. 31); use

VFO B knob

16

Memory Controls

Frequency Memories

The K3 has 100 general-purpose memories (00-99),
plus per-band memories (M1-M4 on each band).
Each memory holds VFO A and B frequencies,
modes, filter presets, antenna selection, and other
settings. Each can have a text label of up to 5
characters (A-Z, 0-9, and various symbols).

The K3 Memory Editor software application
can be used to simplify setup and use of memories.
Refer to our K3 software web page for details.

To store a general-purpose memory (00-9 9):
First tap V M (VFO to Memory), then locate the
desired memory using the VFO A knob. The VFO
A frequencies stored in each memory will be shown
as you scroll through them. When you reach the
desired memory number, tap V M again to store,
or tap M V to cancel the operation.

To recall a general-purpose memory: Tap

M V , then select memory 00 -9 9 using VFO A.

Tap M V again to exit.

Memories 00-09 are quick memories, accessible
with just two switch taps. These could be used to
get to a starting point in each of 10 ham bands.
Memories M 1 – M 4 are per-band quick memories.
For example, you might set up M 1 for each band’s
CW segment, M 2 for the SSB segment, etc.

Memories 00-09 can act as if they were band

switches; see CONFIG:MEM 0-9.

To store or recall quick memories: Tap V M

or M V as before, but instead of rotating VFO A,
tap 0 - 9 or M1 - M4 .

To erase one or more memories: While scrolling
through memories to save or recall, tap C LR . Not
applicable to per-band quick memories (M 1 -M 4 ).

To add or change a memory’s text label: First tap

M V , then select a memory (0 0-9 9) using VFO

A. Next, rotate VFO B to select each label position
in turn as indicated by the flashing cursor. Use VFO
A to change characters. After editing, tap M V
again. (Labels can be edited at any time, including
when you initially store a memory using V M .)

Adding an asterisk (*) at the start of a label
designates a channel-hopping memory (pg. 40).

Digital Voice/Audio Recorder (KDVR3)

The DVR can continuously record receive audio
(up to 90 seconds). To start/stop audio record, hold

AF RE C . To start/stop playback, hold AF PL A Y .

The

icon flashes during DVR use.

Playback position (0-90 sec.) is shown on the VFO
B display; “*” appears if you’re within the most
recent segment. Use VFO B to change the position.

For DVR voice message record/play, see pg. 29.

Message Record/Play Controls

Five switches provide record and playback of
outgoing messages: M 1 , M 2 , M 3 , M 4 and RE C .
These switches provide single-tap play, hold-to­repeat, and other functions that are convenient for
contests and for sending often-repeated text or
voice messages during QSOs. CW messages can be
viewed and edited using K3 Utility, if desired.

For details on CW message record/play, see pg. 30.
The same messages can be used with CW-to-DATA
(pg. 34). For voice message record/play, see Digital
Voice Recorder (pg. 29).

M 1 through M 4 can alternatively be used as tap

or hold programmable function switches (pg. 21).

RIT and XIT Controls

RI T RIT (receive incremental tuning) on/off.

PF 1 Programmable function switch (pg. 21)

XI T XIT (transmit incremental tuning) on/off.

PF 2 Programmable function switch (pg. 21)

CL R Sets RIT/XIT offset to 0. Hold for 2

seconds to copy present RIT offset to VFO
A before clearing.

The RIT/XIT offset control sets the offset for R IT
and X IT . Three LEDs above the control show at a
glance whether an offset is in effect (pg. 11).

If CONFIG:RIT CLR is set to UN DO O N,

tapping C LR will alternate between 0.0 0 and the
last non-zero offset selected, if any.

17

Rear Panel

Connector Groups

The appearance of your rear panel may vary

depending upon the options installed.

Antennas: ANT1 (SO-239) is standard. ANT2

(SO-239) is supplied with the KAT3 ATU option,
which includes an antenna switch controlled from
the front panel. Both jacks are nominally 50 ohms
when the ATU is bypassed. AUX RF (BNC) is for
use with the KRX3 option; see pg. 37 and pg. 41.
ANT3 (BNC, on the KPA3 option panel) is the
antenna jack for the optional K144XV 2-m module.

DC: 12 VDC IN jack is an Anderson PowerPole
connector rated at 30 amps. (See Specifications, pg.
8, for detailed power requirements.)

12 VDC OUT (RCA/Phono) provides up to 0.5 A
(switched) for use with accessory devices.

Ground Terminal: A good station ground is
important for safety and to minimize local RFI.

KPA3: This option panel is blank in the K3/10
except for ANT3 (see above). In the K3/100, the
blank panel is replaced with the fan panel shown,
which includes a circuit breaker.

KIO3 (pg. 18): The KIO3 is an upgradeable digital
and audio I/O module providing computer and
auxiliary control signals, single or dual (stereo)
speaker outputs, line level in (mono) / out (stereo),
and supplemental headphone (stereo) and mic jacks.

KXV3: The KXV3 provides a variety of RF I/O
signals, including receive antenna in/out (pg. 41),
transverter in/out (pg. 39), and a buffered I.F.
output for use with panadapters such as the Elecraft
P3 (pg. 45). The KXV3A also includes internal IF
connections for the K144XV 2-m module.

Keying: PADDLE (1/4” phone jack) is the keyer
paddle input (see CONFIG:CW PDL menu entry).
KEY (1/4” phone jack) can be used with a hand
key, external keyer, computer, or other keying
device. PTT IN (RCA/Phono) is for use with a
footswitch or other external transmit control device.
KEY OUT (RCA/Phono) is the amplifier T-R relay
keying output, capable of keying up to +200VDC
@ 5A.

REF IN (SMA): External 10-MHz reference input
for use with the K3EXREF option module (see
CONFIG:REF CAL and CONFIG:XVn OFS).

18

KIO3 Module

The KIO3 provides serial I/O, control signals, audio
in/out for use with sound cards, speaker outputs,
and auxiliary headphone and mic jacks.

RS232

The RS232 port can operate at up to 38,400 baud. A
straight-through cable is required. If you’re using an
Elecraft P3 Panadapter, the computer is connected
to the P3, and the P3 is connected to the K3.

If you’re building your own cable, you can use as
few as three wires (RXD, TXD, and ground; see
table below). DTR and RTS are optional.

This table uses EIA standard descriptions,
which are from the perspective of the PC. These
differ from K2 documentation, even though the
connections are functionally identical.

Pin #

Description

1,6,8,9

Not used

2

RXD IN (data to PC from K3)

3

TXD OUT (data to K3 from PC)

4

DTR (see PTT and Keying, below)

5

Ground (RF isolated)

7

RTS (see PTT and Keying, below)

RS232 Connector (female, on KIO3 panel)

Serial Port Setup: Set CONFIG:RS232 for the

desired baud rate. Software should be set up at the
same rate; 8 data bits, no parity, 1 stop bit.

DTR and RTS: These are not used as serial I/O
handshaking lines. Instead, the K3 can use these as
PTT IN or KEY IN (see CONFIG:PTT-KEY). The
default for both signals is inactive. Refer to
application software documentation to determine if
it can use RS232 signal lines for PTT or keying.

If a PC or other device asserts RTS or DTR
while you’re using the PTT-KEY menu entry, the
K3 will enter TEST mode as a precaution.

ACC (Accessory I/O)

ACC connector pinouts are listed below.

ACC is not a VGA video connector. The K3

does not provide a video output.

Pin #

Description

1

FSK IN (see FSK Input)

2

AUXBUS IN/OUT (see KRC2 or XV­Series transverter instruction manual)

3

BAND1 OUT (see Band Outputs)

4

PTT IN (in parallel with MIC PTT)

5

Ground (RF isolated)

6

DIGOUT0 (see Transverter Control)

7

K3 ON signal (out) or TX INH (in)
(see Transverter Control, TX INH)

8

POWER ON (see pg. 44)

9

BAND2 OUT (see Band Outputs)

10

KEYOUT-LP (10 mA keying output)

11

DIGOUT1 (see DIGOUT1)

12

Ground (RF isolated)

13

BAND0 OUT (see Band Outputs)

14

BAND3 OUT (see Band Outputs)

15

EXT ALC input (see External ALC,
pg. 27)

ACC Connector (female, on KIO3 panel, viewed

from the back of the K3)

FSK Input (for FSK D Data Mode)

This is a TTL input pulled up to 5V, compatible
with PC outputs. When used with an RS232 signal
from the PC, a level translator is required.

DIGOUT 1

DIGOUT1 is a per-band/per-antenna open-drain
output for controlling antenna switches, preamps,
filters, etc. See CONFIG:DIGOUT1.

19

Band Outputs (BAND0-BAND3)

BAND0-3 provide band selection signals. Their
behavior is controlled by the CONFIG:KIO3 menu
entry (see below). Band data is based on VFO A.

Earlier K3s may require external pullup
resistors to 5 V on these lines, typically 2.2-10K.

In tables below, 0 = 0 VDC, and 1 = 5 VDC.

With CONFIG:KIO3 set to NO R , the BAND0-3
outputs are mapped based on the selected HF-6 m
band as shown below. On Transverter bands,
BAND0-3 will all be set to zero.

Band

BAND3

BAND2

BAND1

BAND0

160 m0001

80 m0010
60 m0000
40 m0011
30 m0100
20 m0101
17 m0110
15 m0111
12 m1000
10 m1001

6 m1010

If CONFIG:KIO3 is set to TR N , BAND0-3 reflect
the parameters of the CONFIG:XVn ADR menu
entry, as shown below. On HF-6 m they’re set to 0.
Addresses INT . TR N0 -9 are used with the K3’s
internal 2-m transverter option (K144XV). IN T

TR N 0 sets all band outputs to 0, while I N T
TR N 1- 9 have the same decodes as T RN 1 -9 .

Transverter addresses are also sent to Elecraft XV­series transverters and the KRC2 via the AUXBUS
line. Note: TR N 1- 7 are sent as 1-7, but TRN 8 and

TR N 9 are sent as 0.

ADR

BAND3

BAND2

BAND1

BAND0

TRN 1

000

1

TRN 2

001

0

TRN 3

001

1

TRN 4

010

0

TRN 5

010

1

TRN 6

011

0

TRN 7

011

1

TRN 8

100

0

TRN 9

100

1

With CONFIG:KIO3 set to H F -TR N, the
BAND0-3 outputs follow the NO R table when HF­6 m bands are selected, and the TR N table when a
transverter band is selected.

Transverter Control

Normally, when the K3 is turned on, a 5-VDC logic
signal appears on ACC pin 7 (K3 ON). This could
be used with Elecraft XV transverters as an enable
signal (pin 8 of J6 on the transverter).

However, pin 7 can alternatively be configured as a
transmit inhibit input line for use in multi­transmitter stations. (See TX INH, below.) In this
case it is not available as a power-on signal for
Elecraft transverters. Instead, the K3’s 12-VDC
switched output could be used for transverter ON.

For transverter keying, you can use KEYOUT-LP
signal (pin 10 of the ACC connector) or the KEY
OUT jack (RCA).

With KIO3 set to TR N or H F -T R N, the DIGOUT0
line (ACC, pin 6) will output 0 V when low power
mode is selected for the current transverter band
(CONFIG:XVn PWR). At all other times,
DIGOUT0 will be floating (Hi-Z).

The K3’s BAND0-2 outputs emulate the

Elecraft K60XV’s XVTR0-2 signals when
CONFIG:KIO3 is set to TR N or HF - TR N.
However, BAND0-2 on the K3 are open-drain
signals, while XVTR0-2 on the K60XV are TTL.

TX INH (Transmit Inhibit Signal)

Pin 7 of the ACC connector can be configured as a
transmit inhibit input by setting CONFIG:TX INH
to LO= Inh (or HI= Inh ). Holding pin 7 low (or
high) will then prevent transmit. An external 2.2 to
10 K pull-up resistor (to 5 VDC) is required.

If TX INH is set to OF F , pin 7 reverts to its

default output function, K3 ON (see above).

Elecraft KRC2 Universal Band Decoder

An Elecraft KRC2 can be used with the K3 to
perform station switching functions; it includes sink
and source drivers for all bands. The KRC2 uses the
AUXBUS rather BAND0-3 (see CONFIG:KRC2
for 6-meter band mapping). Refer to the KRC2
instruction manual for more information.

20

SPKRS

STEREO or MONO; 4 to 8 Ω

Plugging in external speaker(s) cuts off the internal
speaker. A stereo plug is recommended; tip is left
speaker, ring is right. If you only have a mono plug,
set CONFIG:SPKRS to 1 to disable right-channel
audio. (Also see important note below.)

PHONES

STEREO or MONO; 16 Ω min. recommended

The front and rear-panel headphone jacks are both
isolated with series resistors. This allows you to use
mono phones on one jack and stereo on the other, if
required. You’ll need stereo phones for AFX (audio
effects) and stereo dual receive (with sub receiver).

You can plug in headphones and speaker(s) at

the same time, and hear audio in both, if you set

CONFIG:SPKR+PH to YES . However, if you set
CONFIG:SPKRS to 1, setting SPKR+PH to Y E S

will force mono headphone as well as speaker
output. You can set SPKRS to 2 if you use a stereo
plug at the external speaker jack, or if no external
speaker is plugged in.

MIC

MONO; hi- or low-Z

This jack accommodates an electret or dynamic
mic. Use MAIN:MIC SEL to select the rear panel
mic (RP ). Tap 1 to turn on Low or High mic gain
range. Tap 2 to turn bias on/off (see pg. 28 for
recommendations based on mic type).

For the front-panel mic only, additional microphone
gain can be enabled by tapping 3 . Use this only for

very low-output mics.

The mic’s PTT signal, if used, must be routed to
either the PTT IN jack or the PTT line on the ACC
connector (pg. 18).

LINE IN

MONO, transformer-isolated; 600 Ω (nominal)

This input should be connected to your computer’s
soundcard output. The M I C gain control sets the
line input level when the MAIN:MIC SEL menu
entry is set to LIN E IN .

The LINE IN level should be set carefully to
avoid transmit signal distortion due to
saturation of the K3’s input audio transformer.
In addition, sound card gain should be set 6 to 10
dB below the level at which the sound card’s
output stage starts clipping.

LINE OUT

STEREO, transformer-isolated; 600 Ω (nominal)

These outputs can be connected to your computer’s
soundcard inputs. Normally, the left channel is
main receiver audio, and the right channel is sub
receiver audio (if applicable). In this case the
outputs are post-AGC but pre-AF-gain.)

Use CONFIG:LIN OUT to set the level, or to
switch from a fixed-level setting to =PH ONE S .

LIN OUT settings above 10 are usually not
necessary, and can in some cases cause
overloading of either the K3’s output
transformers or the PC soundcard inputs
(typically on noise peaks). Either could degrade
the performance of digital demodulation
software.

Some laptop computers have only very high­gain, high-impedance mic inputs, not line-level
inputs. This can make it difficult to adjust the
K3’s LINE OUT level, and can also worsen noise
pickup. If your laptop has only a mic input, you

may want to add a resistive attenuator between the
K3 and the laptop to keep the signal-to-noise level
high.

21

Basic Operation

This section covers the fundamentals of K3 receive
and transmit operation. It’ll also get you started
using each of the major operating modes.

Once you’re familiar with the K3, please go on to
Advanced Operating Features (pg. 33).

Using Tap/Hold Switches

Most K3 switches have two functions. Tapping
(pressing for less than 1/2 second) activates the
function labeled on the switch. Holding (pressing
for more than 1/2 sec.) activates the function
labeled beneath the switch.

Initial Power-Up

• Connect a power supply (pg. 8); antenna or

dummy load; key, if used (pg. 16); mic, if used,
and station ground (pg. 16).

• Tap P OWE R to turn the K3 on. The LCD

should illuminate and show VFO A/B
frequencies. (Tapping P OWE R again turns
power off.)

• The VFO B display can show a variety of

useful parameters in addition to the normal
frequency display. To see these, tap D IS P (left
of the display), then rotate the VFO B knob.
The VFO B display will cycle through time,

date, RIT/XIT offset, supply voltage, current
drain, etc. (pg. 36). You can use these displays

to make sure the supply voltage is in range (11­15 V), and that current drain is about 1 amp
(higher with sub receiver installed and turned
on). Tap D ISP to return to the normal VFO B
frequency display.

Using the Menus

There are two menus: MA I N and CO N FI G . Most
entries in the CONFIG menu are used for test,
configuration, and alignment, and are used
infrequently.

Nearly all menu entries appear in alphanumeric
order. In the few exceptions to this, adjacent entries
are still closely related.

MAIN Menu

• Tap M ENU to access the main menu. (Tapping

ME N U again exits the menu.)

• Use VFO B to scroll through the menu entries,

referring to the list on pg. 52 for details.

• Change the value (or parameter) of any menu

entry using VFO A.

CONFIG Menu

• Hold CO N FI G (hold function of the M E NU

switch) to access the CONFIG menu.

• Use VFO B to scroll through the CONFIG

menu entries, referring to the list on pg. 53.

Menu Help

Tap D IS P to show help information about the
present menu entry. For most entries, the default
parameter value is shown in parentheses at the start
of the help text.

Programmable Functions

Menu entries that you’d like quick access to can be
assigned to any of the 10 programmable function
switches, PF 1 , PF 2 , and M 1 – M4 (tap or hold).
“Fu n ct i o n” menu entries can only be used via
such a switch assignment. (Examples, from the
CONFIG menu: VFO B->A and TTY LTR.)

To set up a programmable function switch, first use

ME N U or CO N FI G to locate the target menu entry.

Next, hold PF 1 or PF 2 ; or, tap or hold M 1 – M 4 .
For example, if you tap M 2 , you’ll see M2 T S E T
(T for tap), while holding M 2 would show M2 H

SET (H for hold). The assigned switch can then be

used as a shortcut to access that entry. M 1 – M 4 can
each be assigned a tap and/or hold function.

Any M 1 – M 4 switch that is used as a
programmable function switch will not be available
for message play. To cancel a programmable switch
assignment and restore a previously-saved message,
tap R EC , then tap the buffer you’d like to restore
(M 1 – M 4 ), then tap RE C again.

Macros

Programmable switches can also be used to
automate often-used sequences, or macros, such as
“SPLIT, A>B, move VFO B up 5.” Refer to the
CONFIG:MACRO x menu entry, K3 Utility help,
or the K3 Programmer’s Reference.

22

Band and Mode Selection

Tap either end of B AN D to select the desired ham
band (160 through 6 meters). You can use direct
frequency entry (pg. 15), or recall a frequency
memory (pg. 16). Individual bands can be mapped
out if not needed (see CONFIG:BND MAP).

Tap either end of M ODE to select the operating
mode. Hold A L T to select an alternate mode, if
required. This include CW REV (pg. 30), D AT A

RE V (pg. 31), AM - S (synchronous detection, pg.

29), and FM +/- (FM repeater split, pg. 29).

Antenna Selection and Matching

Main Antennas (ANT1 and ANT2)

If you don’t have a KAT3 antenna tuner installed,
connect your antenna to ANT1.

If you do have a KAT3 installed, you can connect
antennas to both ANT1 and ANT2; tap A NT to
select. Holding A T U selects AU TO (autotune
enabled) or BY P ASS mode. In AUTO mode
(AT U icon on), the antenna can be matched for best
SWR by tapping A TU TUN E . Up to 30 ATU
settings are saved for both antennas on every band.
The AT U icon will flash briefly whenever new
settings are automatically loaded.

Tapping A TU T U NE a second time within 5
seconds starts a more extensive match search. The
ATU can even be manually tuned if desired. Refer
to CONFIG:KAT3 for details.

Holding A NT allows names to be assigned to
ANT1 and 2 (e.g., ‘YA G I’). These will be flashed
when you switch antennas. When editing names,
VFO B selects the character position to change;
VFO A cycles through available characters. Setting
the first character to “-” disables name display.

Receive-Only and 2-Meter Module Antennas

With the KXV3 option installed, you can tap R X to
select the receive-only antenna (RX ANT IN/OUT,
pg. 39). The KRX3 sub receiver either shares the
main receiver’s antennas or uses an auxiliary input
(AUX RF, pgs. 37 and 41).

If a K144XV 2-meter module is installed, connect
its antenna to ANT3. Refer to the K144XV manual
for further details.

Using the VFOs

VFO A is both the main receive and transmit
frequency, except during SPLIT, in which case
VFO B controls the transmit frequency (pg.36).
VFO B also controls the sub receiver (pg. 37).

Tap R ATE to select 10 / 50 Hz per step. The faster
rate can be changed using CONFIG:VFO FST.
The number of counts (or steps) per VFO knob turn
can be changed using CONFIG:VFO CTS.
Tapping R ATE briefly flashes either the 10-Hz or
100-Hz digit to indicate slow or fast tuning.

For 1-Hz steps, tap F INE ; for wider steps, use

CO A RS E (see CONFIG:VFO CRS). When F INE

is in effect, a 1-Hz digit will appear in the VFO A
display. When CO A RS E is in effect, the 10-Hz
digit is not shown.

Tap A B once to copy VFO A’s frequency to
VFO B. Tapping A B a second time within 2
seconds also copies VFO A’s filter setup, preamp
state, and other settings to VFO B.

A / B exchanges VFO A and B and their settings.

(Also see CONFIG:VFO B->A.) Pressing R EV
only exchanges the VFOs for as long as you hold
it in. (Exception: When using an FM repeater
offset, R E V permanently swaps RX/TX.)

VFO B and the sub receiver can be set up directly
by holding B S E T . While BSE T is in effect, all
icons and VFO-related controls apply to VFO B
(and to the sub receiver, if turned on; see pg. 37).

Holding S UB links/unlinks the VFOs, while a long
hold (> 2 seconds) turns on diversity mode (pg. 37).

RIT and XIT

The RIT/XIT offset control, at the far right, sets the
offset for R IT and XI T . The offset is shown on the
VFO B display as you adjust the control. Three
LEDs show whether the offset is 0, (-) or (+).

Tap C LR to zero the RIT/XIT offset. Tapping it a
second time restores the offset.

To copy the present RIT offset to VFO A, hold

CL R for 2 seconds. VFO A will be moved to the

new frequency before the offset is zeroed.

If RIT/XIT are both off, the offset control can

coarse-tune VFO A (CONFIG: VFO CRS). Coarse
tuning steps are programmable by mode.

23

Receiver Setup

This section explains how to use basic receiver
controls. Setup for specific operating modes is
described in later sections; see Voice Modes (pg.

28), CW Mode (pg. 30), and Data Modes (pg. 31).

Also see Text Decode and Display (pg. 33) and

Audio Effects (pg. 35).

Receiver Gain Controls

Use AF — SU B (pg. 11) to set the desired main
and sub receiver volume level. There are two
overall audio volume ranges, LO and HI, which can
be selected using CONFIG:AF GAIN.

Usually, both RF — SU B controls will be set
fully clockwise (main and sub receiver RF gain).
You may wish to reduce RF gain to optimize
receiver response to high signal levels or noise.

If the sub RF gain knob has been reconfigured
as squelch for both receivers, then the main RF gain
knob will control RF gain for both receivers. (See
CONFIG:SQ MAIN.)

To improve weak-signal reception, turn on the
preamp using P RE . In the presence of extremely
strong signals, you may wish to use the attenuator
(AT T ), or reduce the RF GAIN setting.

Crystal Filter Selection

You can install as many as five crystal roofing
filters in the K3’s main receiver, and another five in
the sub receiver. For diversity receive, matched
main/sub receiver crystal filters should be used (pg.

38).

Bandwidths as narrow as 200 Hz and variable­bandwidth filters are available, thanks to the K3’s
low first I.F. (intermediate frequency) of 8.215
MHz. See Appendix A for recommended crystal
filter bandwidths for each mode.

To select a crystal filter manually, tap X FIL . The

FL 1 -FL5 icons show the current selection. This

sets the DSP passband to match the crystal filter,
and removes any passband shift or lowcut/hicut.

The K3 will also select the most appropriate crystal
filters automatically as you adjust the S HI F T ,

W ID TH , L O C UT , and H I C UT controls.

Filter Passband Controls

As you rotate the filter controls (shift, width, hicut,
locut), the associated parameter value is shown on
VFO B. The filter graphic shows the width and
location of the passband, as illustrated below. In
these specific examples, segments that turned off as
a result of control movement are shown in gray.

High Cut

Low Cut

Width

Shift

Filter passband controls don’t apply in FM
mode. SHIFT control granularity can be set to
either 10 or 50 Hz in CW and DATA modes; see
CONFIG:PB CTRL. In Sync AM mode (AM - S),
SHIFT selects the upper or lower sideband.

Each passband control has an integral switch. These
switches are used as follows:

Tapping the control alternates between the two
primary functions for that control, for example
HICUT and WIDTH. This is indicated by the
two LEDs above each control.

Holding a control activates its secondary
function, labeled below the control.

Tapping or rotating a control shows the present
setting. To see the settings of both knob functions
without changing them, just tap the control twice.

The secondary functions of the controls are NO R M
and I/I I , described in the following sections.

24

Filter Presets (I/II)

Each operating mode provides two ‘floating’ filter
presets, I and II, which store filter settings on a
per-VFO, per-mode basis (excluding FM). They are
updated continuously as you change filter settings.
(Fixed, per-mode ‘normal’ settings are also
available as explained below.)

You can alternate between the I and II settings by
holding I/ I I. This is especially useful when you’re
alternating between a wide and narrow setting
during contest or DX operation.

The I and II settings for VFOs A and B are
independent.

Filter Normalization (NORM)

Standard Settings

To get quickly to a standard per-mode bandwidth
and reset any passband shift or cut, hold N O RM
(normalize). The normalized AF bandwidth is 400
Hz in CW and DATA modes, 2.7 or 2.8 kHz in SSB
modes, and 3.0 kHz for AM1.

Whenever you normalize the filter passband,
two small "wings" appear at the left and right ends
of the DSP filter passband graphic as shown below.

Moving any DSP control makes the "wings"
disappear, as a reminder that the passband is no
longer normalized.

1

In AM mode, the I.F. bandwidth required for
good fidelity is about twice the AF bandwidth.
This is why a 6 kHz or wider crystal filter is
needed to effectively use the 3 kHz NORM
setting. If a 15 kHz FM filter is installed, it can
be used in AM mode to provide good fidelity at
even higher AF bandwidth settings.

Custom Settings (NORM1 and NORM2)

In addition to the K3's standard "NORM" values,
you can save two of your own setups in each mode,
then recall them using the NO R M function. These
setups are referred to as NORM1 and NORM2.

To save a custom normalization setting:

• set up the filter passband as desired for the

current mode

• hold NO R M until you see <

-

SA V -> (3

seconds)

• rotate the knob slightly left or right to save it as

NO R M1 or N OR M2 .

(The arrows to the left and right of SA V are a
reminder that you can rotate the knob to get to the
two user-defined normalization settings.)

To recall, hold NO R M until you see <

-

N O R ->

(about 1/2 second), then rotate the knob left or right
to recall NO R M1 or N OR M 2.

Narrow DSP Filter Types

For bandwidth settings of 100 Hz or lower, the K3’s
DSP normally uses a type of filter that minimizes
ringing: the Finite Impulse Response or FIR filter.

If you’d like steeper filter skirts, and don’t mind a
small amount of ringing, you can select Infinite
Impulse Response” or IIR filters for these
bandwidths. Locate CONFIG:FLx BW menu entry,
then tap 7 until you see II R ON . Both main and
sub receivers will use the same setting.

IIR filters take longer to change from one
bandwidth to another, so you may hear audio
artifacts when adjusting the DSP controls. If this is
objectionable, use the default FIR filters.

25

Reducing Interference and Noise

The K3 provides several ways to cut interference,
including DSP noise reduction, manual and auto
notch, and noise blanking. Also see Audio Effects
(A FX , pg. 35).

There are actually two noise blankers: one at the
first I.F. (KNB3 module), and the other at the 2nd
I.F. (DSP).

Noise reduction, noise blanking, and notch

filtering should only be used when necessary. These
signal processing techniques are extremely
effective, but can introduce side effects. Sometimes,
reducing the filter bandwidth is the most effective
interference-reduction strategy.

Noise Blanking

First, tap N B to enable I.F. and/or DSP noise
blanking.

Next, hold LE V EL to set the DSP level (VFO A)
and I.F. level (VFO B). You’ll initially see DS P

OF F and IF O F F on the VFO A and B displays.

Rotating VFO A clockwise will turn on the DSP
NB, showing DS P t1 - 1 through DS P t3 - 7. The
first number shows the relative pulse integration
time, and the second shows the blanking level. The
higher the numbers, the more aggressive the DSP
blanking action.

Rotating VFO B clockwise will turn on the IF NB,
showing IF NAR n, IF ME Dn, or IF WID n,
where n is 1 -7 . NA R /ME D /W I D refers to narrow/
medium/wide blanking pulse widths, and n is the
blanking level. Higher n means more aggressive
blanking action. Use NA R width when possible to
minimize strong-signal interaction effects.

The NB icon will flash slowly if the I.F.
blanker setting is too high for the present signal
conditions. If this happens, use a lower setting.

Both the DSP and IF blanking settings are saved on
a per-band basis. If CONFIG:NB SAVE is set to

YES , the on/off status of NB will be also be saved

for each band.

The DSP noise blanker is in the 2nd I.F., where
it can’t be activated by signals outside the crystal
filter passband. It can be used with high-duty-cycle
and complex-waveform noise generated by
computers, switching power supplies, light
dimmers, etc. The I.F. noise blanker is in the 1

st

I.F., where it can use very narrow blanking widths.
It is most effective at blanking AC line noise,
lightning, and other very broadband noise. Often, a
combination of the two is the most effective.

Noise Reduction

Noise reduction reduces random background noise
while preserving meaningful signals. It adds a
characteristic “hollow” sound to all signals.

NR turns noise reduction on. It doesn’t apply to

DATA or FM modes, or with AGC turned off.

Hold A D J to display the NR setting, which is
saved per-mode. Use the VFO B knob to tailor NR
for the present band conditions. In general, the
higher the number, the more aggressive the noise
reduction. Settings F1 - 1 through F 4 -4 are
recommended. F5 - 1 through F 8 -4 use a different
algorithm, where the -x part of the setting indicates
the degree of mix between the DSP-processed and
unprocessed signals (-1 is about 50% processed, - 4
is 100%). A small M appears to remind you that a

Mixed setting is in effect, e.g. N R

M

F5 -1 .

Notch Filtering

Notch filtering removes interfering carriers while
leaving the desired signal relatively unaffected. The
K3 provides automatic and manual notch tuning.

Auto notch will find and remove one carrier, and in
some cases more than one. (SSB mode only.)

Manual notch removes one carrier at a specified
pitch, and can be used in CW and DATA modes as
well as voice. Since manual notching sets up a fixed
(rather than adaptive) notch, it can even suppress a
keyed carrier, i.e. a Morse code signal.

Tap N TC H to turn on notch filtering (NTC H icon).
This turns on Auto notch in SSB mode, and
Manual notch in other modes (adds icon).

Holding M A N UA L directly selects manual notch in
any mode. Adjust the manual notch frequency using
VFO B, then tap N TC H again to exit.