ELECRAFT K3S User manual

ELECRAFT®K3S
HIGH-PERFORMANCE
160 –6METER TRANSCEIVER
OWNER’S MANUAL
Revision A1, May 26, 2015
Copyright © 2015, Elecraft, Inc.
All Rights Reserved

2
Contents
A Note to K3SOwners .................................... 3!
Key to Symbols and Text Styles...................... 3!
Quick-Start Guide............................................ 4!
Introduction...................................................... 7!
K3SFeatures........................................................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!
Control and Audio Connections ........................18!
Basic Operation ............................................. 23!
Receiver Setup...................................................25!
Reducing Interference and Noise ......................27!
Transmitter Setup ..............................................28!
Voice Modes (SSB, AM, FM)...........................30!
CW Mode ..........................................................32!
Data Modes........................................................33!
Advanced Operating Features........................ 35!
Text Decode And Display .................................35!
CW-to-DATA....................................................36!
Tuning Aids: CWT and SPOT ..........................36!
Audio Effects (AFX) .........................................37!
APF and Dual-Passband CW Filtering..............37!
Receive Audio Equalization (EQ) .....................37!
Transmit Audio Equalization (EQ) ...................37!
SPLIT and Cross-Mode Operation....................38!
Extended Single Sideband (ESSB)....................38!
General-Coverage Receive................................38!
VFO B Alternate Displays.................................38!
Alarm and Auto Power-On................................38!
Using the Sub Receiver .....................................39!
Receive Antenna In/Out ................................... 41!
Buffered I.F. Output for Panadapters ............... 41!
Using the 100-550 kHz Range.......................... 41!
Using Transverters............................................ 41!
Scanning ........................................................... 42!
Main and Sub Receiver Antenna Routing ..... 43!
Preamp 2 Limitations........................................ 45!
Remote Control of the K3S............................ 46!
Options and Accessories................................ 47!
Firmware Upgrades........................................ 47!
Configuration ................................................. 48!
Crystal Filter Setup........................................... 48!
Module Enables ................................................ 49!
Miscellaneous Setup ......................................... 50!
VFO A Knob Friction Adjustment ................... 50!
VFO B Knob Friction Adjustment ................... 51!
Real Time Clock Battery Replacement ............ 51!
Calibration Procedures................................... 52!
Synthesizer........................................................ 52!
Wattmeter ......................................................... 52!
Transmitter Gain............................................... 52!
Reference Oscillator ......................................... 53!
Front Panel Temperature Sensor ...................... 54!
PA Temperature Sensor.................................... 54!
S-Meter and RF GAIN Control ........................ 54!
Menu Functions ............................................. 55!
MAIN Menu ..................................................... 55!
CONFIG Menu ................................................. 57!
Troubleshooting ............................................. 69!
Parameter Initialization..................................... 72!
Module Troubleshooting .................................. 73!
Theory Of Operation...................................... 77!
RF BOARD ...................................................... 77!
KAT3A (ATU) and KANT3 ............................ 79!
KIO3B (Audio/Digital I/O) .............................. 79!
Front Panel and DSP......................................... 79!
KREF3 (Ref./2nd LO)........................................ 81!
KSYN3A (Synthesizer) .................................... 81!
Firmware........................................................... 81!
K3SBlock Diagram.......................................... 83!
Appendix A: Crystal Filter Installation.......... 84!
Index .............................................................. 88!

3
A Note to K3SOwners
On behalf of our entire design team, we’d like to thank you for choosing the Elecraft K3Stransceiver.
The K3Sis the same size and weight (~9 lbs.) as its predecessor, the K3. Yet nearly all internal modules have
been redesigned, providing enhanced performance and many new features. These include:
•Ultra low-noise synthesizer for exceptional receiver dynamic range and transmit signal purity
•USB port for convenient, single-cable computer control and digital audio interface (an RS232 port is
provided, as well, for station compatibility and P3 interfacing); pg. 18
•Built-in second preamp for weak-signal work on 12, 10, and 6 meters; pg. 25
•Three attenuator settings (5/10/15 dB) to optimize performance in strong-signal conditions; pg. 25
•Improved audio circuitry for clean, low-distortion stereo speaker output; pg. 80
•Low-loss ATU option with a true bypass relay, maximizing efficiency with every antenna
•Accurate high-speed CW transmit timing, even when using SPLIT, RIT, and XIT
•100-550 kHz coverage, including low-level 630-meter (472 kHz) transmit; pg. 41
Exterior changes include all-stainless-steel hardware, new display bezel, and a soft-touch VFO tuning knob.
With its unique combination of compact size and world-class performance, your new K3Scan handle the most
demanding operating situations, whether you’re at home or halfway around the world.
73,
Wayne, N6KR
Eric, WA6HHQ
Key to Symbols and Text Styles
Important – read carefully
Operating tip
LSB
. .
LCD icon or characters
LED
Enter keypad function
XMIT
TUNE
Tap switch function (labeled on a switch)
Hold switch function (labeled below a switch; hold for 1/2 sec. to activate)
SQL
PWR
MON
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 K3Sright 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} in the text refers to . Later sections provide greater detail on all aspects of K3Soperation.
The first thing you need to know about the K3Sis that most switches have two functions. Tap (press
briefly) to activate the function labeled on a switch. Hold for about ½to 1 second to activate the function
labeled below the switch. In the text, tap functions are shown like this example: MENU . An example of a hold
function is CONFIG . Additional typographical conventions are shown on the previous page.
Try tapping MENU {8}. This brings up the MAIN menu. Rotating VFO B {19} selects menu entries, while
rotating VFO A {22} changes their parameters. Tap MENU again to exit the menu.
1

5
Connections
•Connect a power supply to the DC input jack {26} (see Specifications, pg. 8).
•On the K3S/100, a circuit breaker is provided on the fan panel for the 100-W stage {39}.
•You can power an accessory device from the switched DC output jack {40}(1.0 A max).
•Connect antenna to ANT1 {29} and ground {38}. With an ATU (pg. 24), you can also use
ANT2 {28}. AUX RF {27} is for the sub RX; see pg. 17. ANT3 {30} is used with the
internal 2-m module (K144XV). Connect an RX-only antenna to RX ANT IN {35}.
The Basics
•Press POWER {5} to turn on the K3S. If there are any error indications, refer to pg. 74.
•TAP and HOLD 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 BAND {7} to select a band, and MODE {6} for the mode. Set AF gain
using AF {2}. Set RF to max. Plug phones in at {3}. For SUB controls, see pg. 39.
•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. 38).
•CMP / 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
CMP (compression level) or PWR (power output). Hold the knob in to access its
secondary function, MONitor level. Tap again to restore the primary function.
Filter Controls
•Rotate the SHIFT / LO CUT and HI CUT / WIDTH controls {23} to adjust the filter
passband. Crystal filters FL1-FL5 are automatically selected as you change the band-
width. Tap either knob to select shift/width or hi cut/lo cut. (See filter info, pg. 85.)
•Hold SHIFT / LO CUT to NORMalize the bandwidth (e.g., 400 Hz CW, 2.8 kHz SSB).
•Hold HI CUT / WIDTH to alternate between two filter setups, Iand II (per-mode).
•Tap XFIL {13} to select crystal filters manually; this also removes any passband shift.
Voice Modes
{1}
•Hold METER {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 SWR / PWR (pg. 30).
•Optional: Hold TEST {6} for TX TEST mode; allows off-air TX adjustments (pg. 13).
•Hold CMP / PWR {24} to set speech MONitor level; tap to return to CMP / PWR.
•Hold VOX {7} to select PTT or VOX. Hold SPEED / MIC to set VOX DELAY.
•Details: VOX, pg. 31; TX EQ, pg. 37; MIC SEL, pg. 55; SSB/AM/FM, pg. 30.
CW Mode
{37}
•SPEED {25} sets the CW keyer speed. Hold this knob to set semi-break-in DELAY.
Hold QSK {7} to select full QSK (pg. 32.). Hold VOX {7} to select hit-the-key CW.
•Hold PITCH {18} to set sidetone pitch. Hold CMP / PWR to set sidetone MON level.
•Tap CWT {18} for tuning aid {9} (pg. 36). With CWT on, SPOT auto-spots (pg. 32).
•To select CW text decode/display mode, hold TEXT DEC {18}; rotate VFO B (pg. 32).
•CW keying is converted to DATA in FSK D and PSK D modes (below and pg. 36).
•Hold APF {13} to turn on audio peaking (APF) or dual-passband filtering (pg. 32).
Data Modes
{33}
•Tap MODE {6} until you see the DATA icon turn on (see Data Modes, pg. 33).
•Hold DATA MD {18}. Use VFO B to select from: DATA A (PSK31, JT65, and other
soundcard-based modes), AFSK A (soundcard-based RTTY), FSK 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. APF turns on an RTTY filter (DTF, pg. 34).
•Hold PITCH {18} to select mark tone and shift (for encoder/decoder and RTTY filter).
•Hold TEXT DEC {18} to set up text decode. CWT shows tuning aid (pg. 36).

6
VFOs
and RIT/XIT
•RATE {21} selects 10 or 50 Hz VFO/RIT tuning. See VFO menu entries, pg. 57.
•FINE {21} selects 1-Hz steps. COARSE selects large steps (MAIN menu, VFO CRS).
•Tap FREQ ENT {21} to enter frequency in MHz using numeric keypad & decimal point.
Tap return ( ) to complete the entry, or tap FREQ ENT again to cancel (pg. 15).
•Hold SCAN to start/stop scanning. SCAN must be preceded by a memory recall (pg. 42).
•The RIT and XIT offset knob {17} has LEDs that show -/0/+ offset (pg.16). Tap CLR
{16} to zero the offset. Hold CLR 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 K3Sis in transmit mode. The ∆fLED turns on if the
RX and TX frequencies are unequal, e.g. SPLIT, RIT/XIT, cross-mode (pg. 13).
•XMIT {8} is equivalent to PTT {36}. TUNE puts out full CW power in any mode.
•ATU TUNE {8} initiates antenna matching (pg. 24). ATU enables or bypasses the ATU.
•ANT selects ANT1 or ANT2. RX ANT selects main or RX antenna (KXV3B module).
Preamp and
Attenuator
•Tap PRE {13} to turn on the preamp (pg. 25). On 12-6 m, preamp 2 can be used.
•Hold ATT {13} to turn on the attenuator (pg. 25). Hold ATT for 2 seconds to go into the
MAIN:ATTEN menu entry; per-band attenuation level can be set to 5/10/15 dB.
NB, NR,
and Notch
•Tap NB {12} to enable DSP and I.F. noise blanking. Hold LEVEL to set DSP NB level
(VFO A) and I.F. NB level (VFO B). Fully CCW is OFF in both cases. (Pg. 27.)
•Tap NR {12} to turn on noise reduction (saved per-mode). Hold ADJ to tailor noise
reduction for the present band conditions (pg. 27).
•NTCH {12} turns on auto-notch in SSB mode, manual notch in others. MAN turns on
manual notch in any mode, and is also used to adjust manual notch frequency (pg. 27).
SPLIT,
BSET,
and SUB
•Hold SPLIT {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 BSET {13} to adjust VFO B / sub RX settings independently of VFO A (pg. 39).
•Tap SUB {20} to turn on the sub receiver (pg. 39). VFO B controls its frequency.
•Hold DIV {20} to engage diversity mode (pg. 40), which can reduce signal fading.
•VFO B can be linked (slaved) to VFO A using CONFIG:VFO LNK menu entry.
Memories,
Messages, and
DVR
•To store a frequency memory, tap V M {14}, then: tap M1-M4 {15} to save a per-band
quick memory; or tap 0-9to 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.)
•REC and M1-M4 {15} are also used to record & play voice/CW/DATA messages. The
KDVR3 option is required for voice messages and AF REC / AF PLAY (pg. 31).
Menus and
Switch Macros
•MENU & CONFIG {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 DISP {8} within menus shows information about each entry on VFO B (pg. 55).
•Menu entries can be assigned to programmable switches PF1 , PF2 {16} and M1-M4 {15}
(pg. 55). These switches can also be used to create custom SPLITs, etc. (macros, pg. 23).
Other
Features
•RX and TX EQ (MAIN menu) provide 8 bands of receive/transmit equalization (pg. 37).
•Tap AFX {18} to enable the selected audio effect (see CONFIG:AFX MD, pg. 55).
•Tap DISP {8} and use VFO B to show time, supply voltage, etc. on VFO B (pg. 38).
•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 K3Son at alarm time (pg. 38).
•The KIO3B module provides a rich set of AF {34} and digital {31-33}I/O (pg. 17).

7
Introduction
This comprehensive manual covers all the features
and capabilities of the Elecraft K3Stransceiver. We
recommend that you begin with the Quick-Start
Guide (pg. 4). The Front Panel section (pg. 11)
and Rear Panel section (pg. 17) are for general
reference. Basic Operation (pg. 23) and Advanced
Operation (pg. 35) fill in the details.
Anytime you add new filters or options, refer to
Configuration (pg. 48) for setup instructions.
K3SFeatures
The K3Soffers 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. 25)
•Optional high-performance sub receiver,
also with up to five crystal filters, allows
true diversity receive (pg. 39)
•Second preamp for weak-signal work on
12-6 meters (pg. 25)
•Three attenuation settings (pg. 25)
•Narrow ham-band front-end filters, plus
wider band-pass filters for general-coverage
receive with KBPF3A option (pg. 47);
KPF3A also provides good sensitivity
down to 100 kHz, including 2200-m and
630-m bands (pg. 41)
DSP
•32-bit I.F. DSP for advanced signal
processing, including full stereo and other
binaural effects (pg. 37)
•Passband tuning and programmable
DSP/crystal filter presets (pg. 14)
•8-band transmit and receive EQ (graphic
equalization) (pg. 37)
•Versatile digital voice recorder (DVR)
option (pg. 31)
CW and Digital Modes
•Built-in digital-mode demodulation with
text displayed on the LCD (CW, RTTY,
PSK31/PSK63) (pg. 35)
•APF (audio peaking filter) for digging out
weak signals in CW mode (pg. 32)
•Internal CW-to-RTTY or CW-to-
PSK31/PSK63 encoding for casual digital-
mode QSOs without a computer (pg. 36)
•CW decoded and displayed as you send –
great for improving CW skills (pg. 35)
•Automatic CW/data signal spotting and
manual fine-tuning display (pg. 32)
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. 32)
•Real-time clock/calendar with alarm and
automatic power-on (pg. 38)
•Utility displays show voltage, current drain,
RIT/XIT offset, front panel temperature,
PA heat sink temperature, etc. (pg. 38)
•Built-in menu help text (pg. 23)
•Programmable switch “macros” to
automate often-used operations (pg. 46)
•Custom “power-on banner” can be
displayed on power-up (set up using the K3
Utility program)
Connectivity
•Remote control via USB or RS232 (pg. 46)
•Line-level analog audio jacks, plus digital
audio via the USB port (pg. 17)
•Firmware upgrades via the Internet (pg. 47)
•Front and rear mic and headphone jacks
•Full stereo audio with two speaker outputs
Options and Accessories (pg. 47)
•ATU, sub receiver, digital voice recorder,
100-W PA, 2-meter module, external
reference lock, and other internal options
•Fully integrated P3 Panadapter, 500+ W
KPA500 amplifier and KAT500 automatic
antenna tuner, K3/0-Mini remote control
panel, and other accessories

8
Specifications
Some specifications apply only if the corresponding option modules are installed (see Options, pg. 47).
GENERAL
Frequency Range
Main and Sub Receivers: 100 kHz - 30 MHz and 44-54 MHz (see receiver Sensitivity
spec). Transmitter: Amateur bands between 1.8 and 54 MHz (limits vary by country).
144-148 MHz with K144XV option. 630 m (472 kHz) at ~0.5 mW) with KBPF3A.
Expanded coverage of MARS allocations on request (U.S.).
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.
Frequency Memories
100 general-purpose memories; 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 ant. jack supplied with KAT3A ATU).
BNC jacks for RX antenna in/out and transverter in/out (on supplied KXV3B module).
Modes
USB, LSB, AM, FM, CW, DATA (FSK D [direct], AFSK A [Audio], PSK D [Direct]
and DATA A [Audio]). Built in PSK, RTTY, and CW text decode/display.
VFOs
Dual VFOs (A and B) with separate weighted tuning knobs
Remote Control Port
USB-B port and RS232 port (RJ45 jack plus supplied RJ45 to DE9 adapter). USB port
can also provide line-level audio in/out on the same cable.
Audio I/O
Line-level isolated TX/RX audio interface (mono in, stereo out); front (1/4”) and rear
(1/8”) stereo headphone jacks; stereo speaker jack.
Transverter Interface
Transmit, 0 dBm typ.; XVTR IN/OUT connectors (BNC) on supplied KXV3B
module. KXV3B also includes connectors for K144XV internal 2-meter module.
Buffered IF output
BNC connector (KXV3B); see pg. 41 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. 51 for replacement instructions).
Supply Voltage
and Current
13.8 V nominal (11 V min, 15 V max). 17-22 A typical in TX for K3S/100, 3-4 A
typical in TX for K3S/10. 1.0 A 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 K3S/100; 13.8VDC @
6A for K3S/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, 1.0 A max; 13 V no-load, 12 V max load (@ Vsupply = 13.8 V)
Weight (K3S/100)
Approx. 8.5 lbs. (3.8 kg). With KRX3A 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)
(Typical values, in
500 Hz bandwidth)
HF, Preamp off: -133 dBm. Preamp 1: -138 dBm. Preamp 2 (12/10/6 m): -145 dBm.
Reduced sensitivity near 8.2 MHz (first I.F.) and from 44-49 MHz. Sensitivity
decreases gradually below 1.8 MHz due to intentional high-pass response at the T-R
switch. (Use RX ANT input, XVTR IN, or sub receiver’s AUX input to avoid the
high-pass filter loss.) Note: KBPF3A option required for full general coverage
(including 100 to 1700 kHz). Sensitivity falls off below 200 kHz; MDS typically
-115 dBm at 137 kHz (2200 m band) using RX ANT IN or XVTR IN.
Dynamic Range
IMD3 at 5 and 20 kHz spacing, 500 Hz BW: ~100 dB. Blocking: ~140 dB.
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 1 on; user-adjustable
Preamp
Preamp 1 (all bands): 10 dB; preamp 2 (12/10/6 meters): 20 dB
Attenuator
Main receiver: 5/10/15 dB levels, settable per-band. Sub receiver, 10 dB.
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. See www.elecraft.com for full list of available crystal filters.
TRANSMITTER *
Output Power
K3S/100: 0.1 W –100 W typ. Suggested max from 51-52 MHz, 85 W; 52-54, 70 W.
K3S/10 (or K3S/100 with PA bypassed): 0.1 W –12 W, HF-10 m; 8 W max on 6 m.
XVTR OUT: HF, -10 to +1.8 dBm; at 472 kHz (630 m), -3 dBm (see pg. 41).
K144XV: ~10 W, 144-148 MHz.
Note: K3S/100 output can be set up to 110 W. However, IMD and spurious products
are specified at 100 W, the recommended maximum (lower on 6 m; see 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 or 13 kHz crystal filter)
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
* 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/PSK63), 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). M1-M4 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 OFS knob
below the RIT/XIT switches selects the offset.

12
Display (LCD)
Multi-character displays:The 7-segment display
(upper) shows the VFO A frequency. The 13-
segment display (lower) shows VFO B or text.
Bar graph, receive mode: The bar graph normally
acts as an S-meter. If CWT is turned on, the right
half of the S-meter becomes a tuning aid (pg. 36).
Bar graph, transmit mode: The bar graph
normally shows SWR and RF power output. The
RF scale will be either 5and 10 (low power) or 50
and 100 (high power). In voice and data modes,
transmit scales can be changed to compression
(CMP) and ALC using METER.
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 TEST).
Shows that VFO A or B is locked (see LOCK).
VFO A is the transmit VFO
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. 25.
Filter Icons:
NTCH Notch filtering on (NTCH, pg. 27)
Manual notch (MAN, pg. 27)
I/ II Shows selected preset (I/II, pg. 14)
XFIL Crystal filter selection (FL1-FL5)
Mode Icons:
Basic modes (LSB / USB, CW, DATA, AM, or
FM) are selected by tapping either end (Up/Down)
of MODE .Alternate modes (CW REV, DATA
REV, AM-S, FM +/-) are selected by holding
ALT. LSB and USB are alternates of each other.
+icon on in SSB modes indicates ESSB (pg. 38).
Tindicates FM/tone, CW/DATA text decode, or
AM-Sync auto-tracking.
Other Icons:
CWT CW/data tuning aid on (CWT, pg. 36)
DVR in use (AF REC / AF PLAY, pg. 16)
VOX VOX enabled (VOX, pg. 13)
QSK Full break-in CW enabled (QSK, pg. 32)
NB Noise blanker on (NB, pg. 15)
NR Noise reduction on (NR, pg. 15)
ANT Antenna 1or 2(ANT, pg. 13)
RX RX antenna in use (RX ANT, pg. 13)
ATT Attenuator on (ATT, pg. 15)
PRE Preamp on (PRE, pg. 15); flashes when
preamp2 is selected (pg. 25)
ATU ATU enabled (ATU, pg. 13)
RIT RIT on (RIT, pg. 16)
XIT XIT on (XIT, pg. 16)
SUB Sub receiver on (SUB, pg. 39)
SPLT Split mode in effect (SPLIT, pg. 38)
TX
A
TX
B
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
OFS control is centered, or you tap CLR , the green
LED turns on (offset = 0). Otherwise, the yellow
(-) or (+) LED will be on, indicating the direction of
the offset. See RIT , XIT , and CLR .
Front Panel Connectors
PHONES You can use either mono or stereo
headphones at either the front- or rear-panel
headphone jack. Also see AFX (pg. 37).
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. At present it is used only for factory test.
Primary Controls
BAND Tap left/right end to move among ham
bands. CONFIG:BND MAP disables bands. For
“quick” band switching, see CONFIG:MEM 0-9.
VOX Selects voice-operated or CW keying-
operated transmit (VOX icon on), or PTT (VOX
icon off). Also see DELAY (pg. 32) and CW
VOX auto-off control (CONFIG:CW WGHT).
QSK Selects either full break-in (QSK icon on) or
semi break-in keying, if VOX is selected in CW
mode. Also see DELAY (pg.32).
MODE Tap the left or right end of this switch to
select the operating mode. When DATA is selected,
the DATA MD switch is used to specify DATA-A,
AFSK A, FSK D, or PSK D (pg. 33).
ALT In LSB mode, switches to USB (and vice-
versa). Also selects alternate modes, including:
CW REV, DATA REV, and AM- S (pg. 31). In
FM mode, selects +/-or simplex (pg. 31).
TEST Selects TX TEST (TX LCD icon flashing);
allows key/mic test without actually transmitting.
POWER Turns the K3Son or off. Note: To
ensure correct save of operating parameters,
turn the K3Soff before turning the power supply
off.
MENU Displays MAIN menu (pg. 23).
CONFIG Displays the CONFIG menu (pg. 23).
XMIT Manually-operated transmit. Places the K3S
into transmit mode (same as PTT, pg. 28).
TUNE Puts out a carrier at the present power level.
Also TUNE Power Level (pg. 29).
RX ANT Enables the receive antenna (pg. 24). If
the sub RX is on, holding RX ANT alternates
between the sub’s MAIN / AUX antennas (pg. 39).
DISP Shows an alternate display on VFO B, such
as time, date, voltage, etc. (pg. 38).
METER Selects voice transmit bar graph modes:
SWR and RF, or CMP and ALC (pg. 30).
ATU TUNE Matches the antenna (transmitting at
up to 10 W) using the KAT3A ATU (pg. 24).
ATU Puts the ATU into normal mode (ATU icon
on) or bypass mode (pg. 24).
ANT Selects ANT 1or 2. In BSET mode with the
sub receiver on, selects MAIN or AUX antenna for
the sub receiver (pg. 39).

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 / SQL — 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. 57).
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:
SHIFT Shift passband either direction
LO CUT Adjust low-frequency response
HI CUT Adjust high-frequency response
WIDTH Adjust width of the passband
As these settings change, so does the filter graphic.
Crystal filters are selected automatically (or
manually using XFIL, pg. 15). Also see Filter
Passband Controls (pg. 25).
The secondary functions of these controls are:
NORM 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, NORM1/2, pg. 26.)
I/II Select preset Ior II (per mode)
Presets Iand II each hold a continuously-updated
DSP/crystal filter setup (pg. 26).
Transmit Controls
The primary functions of the transmit controls are:
SPEED Keyer speed in WPM, 8-50 (8-100
if CONFIG:CW QRQ is ON)
MIC Mic gain
CMP Speech compression level
PWR RF output power in watts (pg. 28)
The present transmit mode determines which
primary functions normally apply; for example, in
CW mode, the SPEED / MIC control defaults to
SPEED . You can always tap a knob to override
the present selection.
The secondary functions of these controls are:
DELAY VOX delay (voice/data) or CW semi-
break-in delay, in seconds
MON Voice or data monitor level or CW
sidetone and alert tone 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.
38). VFO B also controls the sub receiver (pg. 39).
The controls to the right of VFO A include:
FREQ ENT Direct frequency entry (pg. 15)
SCAN Start or stop scanning (pg. 42)
FINE Select 1 Hz tuning for both VFOs
and RIT/XIT offset
COARSE Select coarse tuning rate (pg. 24)
RATE Select one of two normal tuning rates
(10/50 or 10/20 Hz; pg. 24)
LOCK Lock VFO A (use BSET to lock B)
SUB Turn sub receiver on/off (pg. 39)
DIV Turn diversity mode on/off (pg. 40)
To link VFO B to VFO A, set CONFIG:VFO
LNK to ON. This is not necessary in diversity
mode, where VFO A always tunes both receivers.
VFO A can optionally be coarse-tuned using
the RIT/XIT offset control if both RIT and XIT are
off . See CONFIG:VFO OFS.

15
Direct Frequency Entry
To jump to any frequency within the tuning range
of the K3, tap FREQ ENT , then enter 1 to 3 MHz
digits, a decimal point, and 0 to 3 kHz digits.
Follow this with Enter ( . . ) to accept or
FREQ ENT 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: FREQ ENT 1825. . .
1.000 MHz: FREQ ENT 1.
50.100 MHz: FREQ ENT 50.1.
For frequencies under 1 MHz, start entry with a
decimal point. If 4 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
BSET Set up VFO B and sub RX (see below)
REV 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)
SPLIT 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 BSET allows VFO B (and the sub
receiver, if on) to be set up directly (pg. 39). As
long as BSET 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 BSET is in effect, they
apply to VFO B (and the sub receiver if turned on).
PRE Preamp on/off; also selects preamp 2
if enabled on 12/10/6 meters (pg. 25)
ATT Attenuator on/off (5/10/15 dB, per-
band; hold switch for 2 seconds to go
directly to MAIN:ATTEN setting)
AGC AGC slow/fast (also see CONFIG:
AGC DCY, AGC HLD, and other
AGC menu entries)
OFF AGC off/on (when off, an AF limiter
is available; see CONFIG:AF LIM)
XFIL Select next available crystal filter
(see CONFIG:FLx ON)
APF CW: APF or Dual-passband filtering
(see CONFIG:DUAL PB);
RTTY: dual-tone filtering (pg. 32)
NB Noise blanker on/off (pg. 27)
LEVEL Noise blanker levels (pg. 27); use
VFO A knob to setup DSP blanker,
and VFO B to setup I.F. blanker
NR Noise reduction on/off (pg. 27)
ADJ Noise reduction parameter adjust; use
VFO B knob (pg. 27)
NTCH Notch filter auto/manual/off (pg. 27)
MAN Manual notch frequency (pg. 27); use
VFO B knob
SPOT Spot tone on/off (manual), or auto-
spot (if CWT is on; pg. 36)
PITCH CW sidetone PITCH, PSK pitch,
FSK / AFSK MARK tone and shift
(pg. 33), or FM tone setup (pg. 31)
CWT CW/data tuning aid on/off (pg. 36);
turn on to use auto-spot
TEXT DEC Text decode, CW or DATA (pg. 35);
use VFO B knob to select mode
AFX Audio effects on/off (pg. 37); use
CONFIG:AFX MD to set mode
DATA MD DATA mode selection (pg. 33); use
VFO B knob

16
Memory Controls
Frequency Memories
The K3Shas 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 Elecraft Frequency Memory Editor
software application can be used to simplify setup
and use of memories. Refer to our K3/K3Ssoftware
web page for details.
To store a general-purpose memory (00-99):
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 00-99 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 M1 – M4 are per-band quick memories.
For example, you might set up M1 for each band’s
CW segment, M2 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- 9or M1 - M4 .
To erase one or more memories: While scrolling
through memories to save or recall, tap CLR. Not
applicable to per-band quick memories (M1-M4).
To add or change a memory’s text label:First tap
M V , then select a memory (00-99) 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. 42).
Digital Voice/Audio Recorder (KDVR3)
The DVR can continuously record receive audio
(up to 90 seconds). To start/stop audio record, hold
AF REC . To start/stop playback, hold AF PLAY .
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. 31.
Message Record/Play Controls
Five switches provide record and playback of
outgoing messages: M1 , M2 , M3 , M4 and REC.
These switches provide single-tap play, hold-to-
repeat, 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. 32.
The same messages can be used with CW-to-DATA
(pg. 36). For voice message record/play, see Digital
Voice Recorder (pg. 31).
M1 through M4 can alternatively be used as tap
or hold programmable function switches (pg. 23).
RIT and XIT Controls
RIT RIT (receive incremental tuning) on/off.
PF1 Programmable function switch (pg. 23)
XIT XIT (transmit incremental tuning) on/off.
PF2 Programmable function switch (pg. 23)
CLR 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 RIT
and XIT. Three LEDs above the control show at a
glance whether an offset is in effect (pg. 11).
If CONFIG:RIT CLR is set to UNDO ON,
tapping CLR will alternate between 0.00 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 KAT3A 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 KRX3A option; see pg. 39 and pg. 43.
ANT3 (BNC, on the KPA3A 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 1.0 A
(switched) for use with accessory devices.
Ground Terminal: A good station ground is
important for safety and to minimize local RFI.
KPA3A: This option panel is blank in the K3S/10
except for ANT3 (see above). In the K3S/100, the
blank panel is replaced with the fan panel shown,
which includes a circuit breaker.
KIO3B (pg. 19): Provides computer, auxiliary
control, and audio connections. The USB
connector handles both digitized line-level audio
and data (pg. 18). The RS232/P3 jack (RJ45) is
used with the P3 and/or for RS232 station control;
an RJ45-DE9 adapter is included (pg. 19).
KXV3B: Provides a variety of RF I/O signals,
including receive antenna in/out (pg. 41),
transverter in/out (pg. 41), a buffered I.F. output for
use with the Elecraft P3 (pg. 47), and internal I.F.
connections for the K144XV 2-m module. Preamp
2, for weak-signal work on 12/10/6 m, is also
included on this module (see pgs. 25 and 45).
External preamps such as the PR6-10 are not
needed with the K3S. See Preamp 2 (pg. 25).
Keying: PADDLE (1/4” jack) is the keyer paddle
input (see CONFIG:CW PDL). KEY (1/4” jack)
can be used with a hand key, external keyer,
computer, or other device. PTT IN (RCA/Phono) is
for use with a footswitch, etc. 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
Control and Audio Connections
The K3Sprovides a full complement of station
control and audio interfaces on the KIO3B panel.
These interfaces are described in this section.
USB Port (Control and Audio)
The USB port can be used for computer-based
remote control. It also acts as the equivalent of a
built-in USB sound card, eliminating the need for
external converters and additional cables.
A single USB cable can handle all of these interface
requirements:
•commands from logging/contesting software
•line-level audio input/output (audio is digitized
by the KIO3B’s USB interface)
•PTT and CW keying (via “DTR” and “RTS”)
Most software applications will work with USB
instead of RS232. They will recognize the
transceiver’s USB port as a “COM” port, and/or as
a sound device, selectable from within the
application.
An Elecraft P3 Panadapter can be connected
directly to the K3Seven when the USB port is used
with your computer. See details at right.
To connect a computer to the K3Svia USB:
•Connect the supplied USB cable from the K3S
to any available USB port on your computer.
(See illustration below.)
•If you also have a P3, connect it to the
RS232/P3 port as shown, using an Elecraft
model CBLP3Y cable.
•Set the CONFIG:RS232 menu parameter to
USB. Exit the menu.
•With the USB cable plugged in and the K3S
turned on, determine which COM or sound
device ports have been assigned to the K3S.
This can be done from within applications. On
Windows PCs, an alternative is to locate the
Device Manager (Start > Control Panel >
System > Hardware), and view its list of Ports.
When you plug in the USB cable from the K3S,
a new COM port will appear in the list.
•If you plan to do PTT or CW keying from the
computer, see PTT and Keying (next page).
Optional: Using LINE IN/OUT jacks with USB
We recommend using the digital audio line-in/out
capability provided by the USB cable. The analog
LINE IN/OUT jacks can then remain unconnected.
See pg. 22 for further details on LINE IN/OUT.

19
RS232 / P3 Panadapter Port (RJ45)
The RS232/P3 port can be used with an Elecraft P3
Panadapter, or with a computer’s RS232 interface.
In most cases it is preferable to connect the
computer to the transceiver’s USB port as described
on pg. 18. However, RS232-only installations can
also be used, as discussed on this page.
An adapter cable to convert RJ45 to DE9 (RS232
standard, female) is supplied with the K3S (Elecraft
#E980297). This adapter allows you to connect the
K3Sto a P3, or to a computer via a user-supplied
RS232 cable, as shown below. The adapter cable’s
DE9 connections are shown on the next page. RJ45
jack connections are shown below.
If you plan to use the RJ45 jack for PTT or keying
from the computer, see PTT and Keying (pg. 20).
Typically such connections would be made at the
DE9 end of the supplied adapter, rather than
directly at the RJ45 jack.
To connect a P3 Panadapter to the K3S, and
optionally connect a computer to the P3 (via
RS232):
•Use the supplied Elecraft #E980297 cable to
connect the P3 to the K3Sas shown (see
illustration below). At the K3Send, the cable
is connected to the RS232/P3 jack. At the P3,
the cable connects to the XCVR jack.
•A computer can optionally be connected via
RS232 to the P3’s PC jack as shown. The cable
is user-supplied. (See DE9 signals, next page.)
•Set CONFIG:RS232 to 38400.
To connect a computer to the K3Svia RS232,
without a P3 Panadapter:
•Connect the RJ45 end of cable # E980297 to
the K3Sas shown below. Connect the DE9 end
to a computer, using an additional user-supplied
cable if required.
•Set CONFIG:RS232 to the desired baud rate.

20
RS232 Adapter Cable
The supplied Elecraft #E970297 cable converts
from RJ45 (at the K3Send) to DE9 (RS232
standard). The DE9 end can be connected to a P3’s
XVTR jack, or to a computer’s RS232 port. The
pinout for this end of the adapter is shown below.
If an additional RS232 cable is required to reach
your computer, it can be wired straight-through,
using as few as three wires (RXD, TXD, and
ground). DTR and RTS are optional.
This table uses EIA standard descriptions,
which are from the perspective of the PC.
Pin #
Description
1,6,8,9
Not used
2
RXD IN (data to PC from K3S)
3
TXD OUT (data to K3Sfrom PC)
4
DTR (see PTT and Keying, below)
5
Ground (RF isolated)
7
RTS (see PTT and Keying, below)
RS232 adapter cable DE9 connections (female)
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.
PTT and Keying (via DTR and RTS)
In the K3S, these are not used as serial I/O
handshaking lines. Instead, the K3Scan 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.
Use these signals with caution. A computer
may assert DTR or RTS during power-up, causing
the K3Sto transmit unexpectedly. If a computer or
other device asserts RTS or DTR while you’re
using the PTT-KEY menu entry, the K3Swill enter
TEST mode as a precaution, allowing you to
change the menu setting if required.
ACC (Accessory I/O)
ACC connector pinouts are listed below.
ACC is not a VGA video connector. The K3S
does not provide a video output. (The P3 does
have an SVGA video output option; see pg. 47.)
Pin #
Description
1
FSK IN (see FSK Input)
2
AUXBUS IN/OUT (see KRC2 or XV-
Series 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
K3SON signal (out) or TX INH (in)
(see Transverter Control, TX INH)
8
POWER ON (see pg. 46)
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. 29)
ACC Connector (female, on KIO3B panel)
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 output for
controlling external gear. See CONFIG:DIGOUT1.