ELECRAFT® KX3 ULTRA-PORTABLE 160-6 METER, ALL-MODE TRANSCEIVER OWNER ’S MANUAL Revision C2, August 13, 2013 Copyright © 2013, Elecraft, Inc.
Contents Transmit Noise Gate ......................................... 21 Transmit Inhibit and External PTT ................... 21 Cross-Mode Operation and CW-in-SSB .......... 21 Transverter Bands ............................................. 21 Special VFO B Displays ................................... 22 Extended Single Sideband (ESSB) ................... 22 Introduction .................................................... 3 Key to Symbols and Text Styles.....................
Introduction On behalf of our entire design team, we’d like to thank you for choosing the Elecraft KX3. The KX3 is a compact, 160-6 meter, all-mode transceiver that’s ideal for both new and experienced operators. Its unique features meet the requirements for home station use, portable, mobile, and even hand-held operation. Since the KX3 is a software-defined-radio (SDR), you’ll be able to extend its capabilities using computer applications, and add new features via free firmware upgrades.
Installation § § § § CAUTION Power Supply Be careful when plugging in cables. Avoid applying sideways pressure that might damage the KX3’s left-side jacks. Avoid operating in wet conditions (rain, snow, spray, etc.). The KX3 is not waterproof. Avoid operating at very high temperatures. The KX3 can be damaged by electrostatic discharge (ESD). Prior to opening the case, touch a grounded, unpainted metal surface. For fixed-station use, a low-noise 12-14 VDC power supply or battery is recommended.
Computer/Control Port (ACC1) Avoid using bulky connectors or adapters that could put excessive stress on side-panel jacks. Lightweight cables, preferably with rightangle plugs, are strongly recommended. The 3.5-mm stereo ACC1 jack allows firmware updates, configuration, and remote control of the KX3 via a computer. The jack can be connected to a computer’s USB port via the Elecraft model KXUSB cable, or to an RS232 port via the model KXSER cable. (The jack’s tip connection is RX data from the computer.
Antennas Grounding and ESD Protection You can use any resonant antenna having a 50-ohm (approximate) load impedance with the KX3. Examples can be found in the ARRL Antenna Handbook and other sources. A simple inverted “V” or dipole can be very effective. A ground system using buried rods and/or a ground counterpoise (wires radiating out from the antenna) can reduce receive interference and help prevent electrical shock or damage due to electrostatic discharge (ESD).
Control Panel Reference This section summarizes all KX3 controls. For details, see Basic Operation and Advanced Operating Features. To Turn Power ON/OFF: Hold both the B A N D - and A T U T U N E switches for 2 seconds. (See ON/OFF label on left side.) Tap Functions: Tap a switch or knob briefly to activate the function labeled on or above it, e.g. RATE . Hold Functions: Hold the control for about 1/2 second to activate the function labeled below, e.g. KHZ .
Display (LCD) Bar graph, receive mode: Shows RX signal strength in S-units (S-meter). If C W T is turned on, the right half of the S-meter becomes a tuning aid (pg. 13). Reducing RF gain adds a moving reference segment (pg. 12). VFO Icons: Shows that a VFO or menu entry is locked. The TX icon points to the transmit VFO: A Bar graph, transmit mode: Shows antenna S W R and R F output (pg. 14). In voice modes, shows C M P (compression) and A L C (mic level) when mic gain or CMP are set (pg. 15).
AF Gain and other Knob Functions Basic Operation Each of the four small knobs has a primary function that is in effect when you turn on the KX3. For example, the knob at far left, AF / RF-SQL , normally controls receiver AF gain (volume). As you rotate this knob, the AF gain setting is displayed in the VFO B area. This section describes basic KX3 controls and features. Once you’ve mastered the basics, you’ll be ready to explore the Advanced Operating Features section (pg.
Band Selection Mode Selection The KX3 covers the 160-6 m amateur bands. Characteristics of each band are summarized below. For further information, see the ARRL band plan: Each mode is described briefly below. Later sections cover each mode in detail. Tap M O D E one or more times to select SSB, CW, AM, or FM mode. A L T selects alternate modes, such as CW reverse. Tap D A T A to select data mode. To select a data sub-mode, tap D A T A again, then rotate OFS/VFO B . http://www.arrl.
VFOs A and B VFO A and B swap: Tap A / B to exchange VFO frequencies, modes, and all other settings. The KX3 provides two VFOs (see glossary, pg. 50). Use of VFO B is optional. The VFO knobs are located in the area shown below. Each VFO has independent frequency, mode, and filter settings. VFO A/B temporary reverse: Sometimes you’ll want to swap the VFOs temporarily to look for an open transmit frequency when operating split (pg. 19). In this case, hold R E V .
Receive Settings Passband Tuning Functions (PBT I/II) The RX control group, shown below, is used to set up the KX3’s receiver. Directly above these controls is the filter passband graphic, which shows the shape and position of the receiver’s passband. This determines what pitch range you’ll hear. The P B T I / I I control is used to shape the KX3’s receive filter passband. In general, a narrow passband reduces interference (QRM) and noise (QRN), while a wider passband improves fidelity.
Preamp and Attenuator CW/DATA Tuning Aid (CWT) P R E turns on the RF preamp. It should be used only when signals are very weak. Preamp gain can be set on a per-band basis using MENU:PREAMP. A T T N turns on the 15-dB RF attenuator, which can protect the receiver from strong interfering signals. Accurate tuning of received signals is required before you call a station, or when you’re using built-in text decode (T E X T , pg. 16). Tuning can be done by ear.
Transmit Settings selects the keying mode: PTT (push-to-talk) or VOX (voice- or keying-operated transmit). With PTT selected, the transmitter is enabled by tapping X M I T or by holding the mic’s PTT button. With VOX selected, the V O X icon turns on, and transmit starts by speaking (voice modes) or when keyed (CW mode). Also see D L Y (at left) and MENU:VOX GN (p. 35). VOX The TX control group is used to set up the KX3’s transmitter. The TX LED turns on during transmit.
Voice Modes (SSB, AM, FM) Transmit Metering in Voice Modes Basic Voice-Mode Setup Normally, the SWR/RF bar graph is active during transmit in all modes. In voice modes, you can switch to the C M P / A L C bar graphs by tapping K E Y E R / M I C . This also occurs automatically if you adjust mic gain or speech compression level. To avoid transmitting a signal during voicemode setup, you can set P W R to 0.0 watts. § Choose a mode: Tap M O D E to select L S B /U S B , A M , or F M mode.
CW Mode CWT, SPOT and Auto-Spot Basic CW-Mode Setup When calling a station, you should try to match your frequency to theirs. To facilitate this, the KX3 provides both manual and automatic spotting for CW, FSK-D, and PSK-D signals. See pg. 13. § § Mode selection: Tap M O D E to select C W (CW normal). In some cases an interfering received signal can be eliminated by switching to C W R E V (CW reverse) using A L T . This doesn’t affect transmit.
Scanning Advanced Operating Features Scanning allows the KX3 to tune any portion of a band continuously. Normal scanning mutes the receiver until a modulated signal is found. “Live” scanning keeps the receiver unmuted, and is stopped by the operator. This is useful on very quiet bands. Frequency Memories The KX3 has 100 general-purpose frequency memories (0 0 -9 9 ), plus four quick memories on each band, accessed by tapping 1 - 4 on the numeric keypad.
Data Modes PSK D Mode (PSK31) The KX3 supports data operation via a computer and special software. But it can also be used in RTTY and PSK31 modes without a computer via the KX3’s built-in FSK D and PSK D modes. PSK D is the KX3’s built-in implementation of PSK312, a narrow-band data mode which is reliable even at very low power levels. 5 watts or less is strongly recommended to keep distortion low. 5.0 watts or lower is recommended in all data modes.
Text Decode And Display Split and XIT The KX3 can decode CW, PSK31 (PSK D) and RTTY (FSK D). CW speeds from about 8 to 70 WPM can be decoded. Decoded text is displayed on VFO B. If no signal is tuned in, random characters may be displayed. Sometimes you’ll hear a DX station being called by many other stations. To ensure that he has a clear transmit channel, the DX station may say “UP” or “DOWN” to indicate that he’s listening above or below his transmit frequency.
Audio Effects Receive Audio Equalization (RX EQ) If you have stereo headphones or stereo external speakers, you can take advantage of the KX3’s DSP audio effects (AFX). These create an illusion of greater acoustic “space,” resulting in a lessfatiguing receiver sound and in some cases better copy of weak signals. The KX3 provides 8 bands of receive audio equalization via the RX EQ menu entry.
SSB/CW VFO Offset Transverter Bands The KX3 can automatically offset the VFO frequency when you switch from SSB to CW mode, so other stations will hear the correct CW pitch. See MENU:CW WGHT for details. Nine user-definable bands are provided for use with transverters. These can be used with the Elecraft KX3-2M internal 2-m module, Elecraft XV-Series, or other transverters.
Special VFO B Displays § The KX3 can continuously display time of day or one of several operational parameters on the VFO B display. To access these displays, tap D I S P , then rotate the O F S / V F O B control. The available special displays are listed below. § 24-hour time obtained from the real-time-clock on the KXBC3 option module. If a KXBC3 is not installed, the time since last power-on will be displayed. To set the time, use the TIME menu entry.
Internal Batteries The KX3’s internal battery pack can be used with eight 1.2-1.6 volt AA cells of any type. The pack typically provides 4-6 hours of casual operation, ideal for field use or as backup during power outages. An internal NiMH charger is also available (KXBC3, pg. 24). Opening the Enclosure To open the enclosure for battery installation, unplug the KXPD3 paddle, then follow the steps below. 1 Loosen all four thumb screws. Then slowly pull the halves apart only about 1/4” (6 mm).
To maximize Battery Life: § § § § § VFO Friction Adjustment Set power to 3.0 W or less when possible. This uses a high-efficiency transmit mode. Turn off the backlight (BKLIGHT) and the isolation amp (RX ISO) when not needed. Use headphones. Use the auto-off timer (AUTO OFF). Use BAT MIN to set up an appropriate BAT LOW warning level for your battery type. Note: Regardless of the BAT LOW warning level, the KX3 will turn itself off if the power supply or battery goes below 7.5 volts.
Options and Accessories Firmware Upgrades This section describes all available KX3 options and accessories. Option modules are easily userinstallable, in any order, without soldering. New features and improvements are available to all KX3 owners via firmware upgrades. Upgrades may also be required when you install option modules. MH3 Hand mic: The MH3 was designed specifically for the KX3. It includes a high-quality mic element, rugged right-angle plug, PTT switch, and VFO UP/DN function buttons.
SDR Applications groups for your program that can help if you have difficulty understanding its installation or operation. The KX3 provides a special receiver output jack, RX I/Q, for use with software-defined radio (SDR) applications3 running on a computer or other device. A PC program suitable for most purposes is “HDSDR”. It is available as of this writing at http://www.hdsdr.de Follow the directions provided by the HDSDR program for setup and operation. Another popular SDR program is “NaP3”.
including the apparent noise floor of the receiver, will “roll off” by these amounts. § If you have an accurate signal level source (such as an Elecraft XG-series signal source or a signal generator), you can calibrate the signal amplitude following directions provided by the SDR program. § After you are comfortable with setting up and using the spectrum display, you can connect the USB/serial cable between the PC and the KX3.
Remote Control of the KX3 function cannot be used for power-on control. Use only the MIC PTT line.) Computer Control and Logging To turn the KX3 off, the controller must send the KX3 a “PS0;” command via the ACC1 jack (RS232 or USB, depending on the cable used). If the controller also turns off the KX3’s power supply, it should first allow 100 ms for the KX3 to shut down. With appropriate software, any computer with an RS232 or USB port can be used to control the KX3.
Configuration Menu Settings The menu entries described in this section can be used to tailor KX3 operation to your own needs. You may also want to review the full list of menu entries, starting on pg. 35. You’ll need to set up Option Module Enables (see below) anytime you add one or more option modules. This is done at the factory for factoryinstalled options. Some Menu Settings (beginning at right) should be set up before you use the KX3 on the air.
Band Map Setting the Time If there are some bands you don’t plan to use, you can remove them from the band-switch rotation using BND MAP. This can save time when switching bands. Within the BND MAP menu entry, you can switch bands using B A N D + and B A N D - . Set each band to I N or O U T as desired. MENU:TIME sets the 24-hour real-time-clock (RTC) if a KXBC3 module is installed. If no KXBC3 is installed, the displayed time will start at 0 0 : 0 0 : 0 0 when the KX3 is turned on.
Method 2 (manual tuning): This method requires manually matching the pitch of the received signal to the CW sidetone pitch using S P O T . To prepare for this, you may need to increase sidetone volume. See pg. 12. Calibration Most calibration steps are performed at the factory for both kit and assembled KX3s. There is one exception: If you install a KXFL3 roofing filter after initial purchase, you’ll need to perform the Receive Sideband calibration step (pg 32).
Receive Sideband Transmit Bias Receive sideband calibration nulls (rejects) the opposite-sideband image. This image is a weak audible side-effect of very strong signals. This automated procedure sets the transmit bias current of the 10-watt amplifier stage to ensure low distortion. No test equipment is required. This calibration step is done at the factory for KX3s shipped with the KXFL3 option at time of purchase, whether factory assembled or kit.
Transmit Gain This procedure compensates for per-band transmit gain variations at two different power levels, and must be done on every band. As described below, the procedure can be done manually, or you can use the a fully-automated procedure provided by the KX3 Utility program. A 6-watt (minimum) dummy load is required in either case. A 12-14 volt external power supply or battery must be used during this procedure.
Transmit Carrier Transmit Sideband In SSB and some data modes, a transmitter’s primary signal may be accompanied by a weak unmodulated signal called a carrier about 1 kHz away. The carrier should be suppressed (or nulled) to minimize interference to nearby stations. The TXCRNUL menu entry is used for this purpose. In SSB and some data modes, a transmitter’s primary signal may be accompanied by a weak opposite sideband signal about 2 kHz away.
Menu Functions Hold M E N U to enter the KX3’s menu. Tap or hold this switch to exit. Menu entries that you’d like quick access to can be assigned to programmable function switches (pg. 19). Note: N O R appears in some parameter displays. This means “Normal,” i.e. the default or recommended value. Menu Help Information Holding M E N U for about 3 seconds while in the menu shows information about the present menu entry on VFO B.
AGC SPD SLO AGC*THR 007 ALARM OFF AM MODE ON ATU MD AUTO INF Not Inst NOR AUTO OFF INFINITE BAT CHG Not Inst BAT MIN 10.0 BKLIGHT ON This setting is stored per-mode. The default for CW mode is F A S T , and for other modes, S L O . The setting is indicated by the A G C S and F display icons. This menu entry provides access to several AGC parameters, each of which starts with A G C * . For most purposes the defaults will suffice.
BND MAP {band} In COR LVL NOR 0.1 CW IAMB A CW KEY1 TIP=DOT CW KEY2 LFT=DOT CW WGHT 1.25 with the backlight turned off. Turning it off will extend battery life. Allows you to remove one or more bands from the B A N D rotation. Use B A N D up/down to select bands, then set them to I n or O u t using VFO A. (Works with transverter bands, too.) You can still get to mapped-out bands using memory recall, direct frequency entry, or computer-control commands.
MSG RPT 6 PA MODE OFF including the Heil models available from Elecraft. Third-party mics may not have a KX3-compatible PTT (push-to-talk) switch. You can still key the transmitter either by tapping the X M I T switch or by using VOX (pg. 15). Message repeat interval in seconds (0 to 2 5 5 ). To repeat a message, hold M 1 – M 4 rather than tap. A 6 - 10 sec. interval is about right for casual CQing. Shorter intervals may be needed during contests, and longer for periodic CW beacons.
RX NR p See descr. RXSBNUL GAIN nnn RX SHFT NOR RX XFIL Not Inst SER NUM SMTR MD N/A NOR SW TEST OFF SW TONE ON TECH MD TIME OFF N/A Note 1: Most operators will not need to use this menu entry, which provides fine control of receive noise-reduction parameters. The N R switch function provides convenient control of the most important parameter (wet/dry mix); see pg. 13.
TUN PWR NOR TX BIAS TXCRNUL ppp qqq 1 nnnn TX EQ +0 dB, each band TX ESSB OFF 3.0 TX GAIN ALC nn TX GATE OFF 0 TXSBNUL GAIN nnn VFO CRS Per-mode VFO CTS 256 VFO NR OFF VFO OFS ON maintained if a KXBC3 option module and an internal battery are installed. If set to N O R , T U N E power level follows the POWER knob. Otherwise, establishes a fixed power level for T U N E , overriding the present POWER knob setting.
VOX GN 030 VOX INH 000 WATTMTR 1.00 XVn ON NO XVn RF 144 XVn IF 28 XVn PWR H 0.1 XVn OFS 0.00 XVn ADR TRNn Adjusts the sensitivity of the VOX to match your mic and voice. Set to trigger at normal speech level, but not in response to incidental noise. Start with low settings (10-20). Adjusts immunity of the VOX circuit to false triggering by speaker audio. (Also known as anti-vox.) A setting of about 30 is a good starting point.
Troubleshooting The most common symptoms and their causes are listed below, in three categories (general, transmit, and receive). Most problems are related to control settings. If the problem persists, please contact Elecraft support (see pg. 53) or post a question on our email reflector. General § MCU LD shown on LCD and TX LED flashing: Do a forced firmware load (pg. 25). § ***** shown on LCD: This indicates that the KX3 did not power-down correctly.
§ H I C U R or H I S W R warning: Check supply voltage. If voltage is low and/or a low-impedance antenna load is present, current can go up for a given requested power level. Reduce power if necessary. (The KX3 may do this automatically. If this doesn’t reduce the current or reflected power to safe levels, the KX3 will drop out of transmit mode.) § H I T E M P warning: PA heat sink temperature has exceeded the safe operating limit.
§ Spurious signals (“birdies”): All receivers exhibit some birdies. Most will be inaudible with an antenna connected. In the KX3, there may be significant birdies or harmonics of birdies at the following frequencies due to internal signal sources: 16000 and 18432 +/- 5 kHz (MCU and DSP clock frequencies), 300-900 kHz (DC-DC converter oscillators, CMOS RF switches). In the unlikely event that a birdie interferes with operation, try CW reverse, manual notch, or (in voice modes) auto-notch.
Error Messages (ERR nnn) Error messages may be displayed on VFO B at power-up or during normal operation. In many cases error messages are due to a problem with a single option module or incorrect firmware configuration. If you see an error message on VFO B (E R R n n n ): Write down the error message, as well as any associated error data shown on the VFO A display (e.g. d = 0 0 5 ). Then tap any switch to clear the error code.
ERR KEY, ERR PTT Attempt to key the transmitter or activate PTT during poweron sequence. (Note: If ERR PTT occurs, VOX transmit is disabled in all modes. Reenable using the V O X switch.) ERR OSC Synthesizer IC unresponsive ERR RFB RF board may be disconnected from Control Panel board RF board relay test failure (on VFO A, d = n n n identifies the failing relay, e.g.
Theory Of Operation This section includes: § a functional description of the KX3’s RF, control panel, and option PC boards § block diagram of the KX3 (pg. 49) § glossary of selected technical terms (beginning on pg. 50) Additional information including an FAQ (answers to frequently asked questions) can be found on the Elecraft web site. RF Board The RF PCB (Printed Circuit Board) contains all of the KX3’s RF circuitry as well as low-level baseband (AF) stages in the receive path.
MOSFETS allows automatic reduction of power if they become too hot during long transmit periods at high power levels and high ambient temperature. The optional KXAT3 automatic antenna tuner (ATU) option connects between the BNC antenna jack and the RF board’s SWR/power bridge and low pass filters. It uses a latching relay-switched “L network” with eight inductors and eight capacitors capable of matching a wide range of antenna impedances.
KX3 Block Diagram 49
Glossary of Selected Terms The following terms are often used in the discussion of amateur radio transceivers and related equipment. All are directly applicable to the KX3, which is used here to illustrate some of the concepts. A much larger glossary of terms can be found in the ARRL Handbook and on numerous web sites. ________________ A-to-D or ADC (analog-to-digital converter): An integrated circuit that converts analog electrical signals such as audio or RF into digital form.
to great lengths to minimize distortion, trading off circuit cost and complexity against the benefit of reduced interference. Keyer: A device that partially automates the sending of Morse code, allowing for faster code speeds. The KX3 has a built-in keyer function, as well as an optional attached keyer paddle (KXPD3, pg. 25). Linear power supply: A power supply that provides a well-regulated DC output voltage using analog regulator circuitry.
Specifications GENERAL Frequency Range 310 kHz - 32 MHz and 44-54 MHz; 144-148 MHz with KX3-2M option. Transmit excluded in some ranges (varies by country). See receiver sensitivity note below.
Customer Service and Support Technical Assistance You can send e-mail to KX3support@elecraft.com and we will respond quickly – typically the same day Monday through Friday. If you need replacement parts, send an e-mail to parts@elecraft.com. Telephone assistance is available from 9 A.M. to 5 P.M. Pacific time (weekdays only) at 831-763-4211.
Index ACC1 and ACC2 Jacks, 5 Advanced Operating Features, 17 AF Gain Control, 12 AF Limiter, 35 AFSK A Mode, 18 AFV, 22 AFX (Audio Effects), 20, 29 AM Mode, 10, 15, 29 Analog To Digital Converter (ADC, A-to-D), 50 Antenna, 33 Antenna Jacks, 6 Antenna Recommendations, 6 Anti-VOX, 15 Attenuator, 13, 50 Audio Effects (AFX), 20, 29 Audio Peaking Filter (APF), 13 Auto Info (AI Mode), 36 Auto Power-Off, 29 Automatic Antenna Tuner (ATU), 6, 14, 36, 50 Auto-Notch, 13 Auto-Spot, 13, 16 Band Mapping, 30, 37 Band Sele
KX3 Utility PC Application, 25, 28, 44 KX3-2M, 25, 29 KXAT3, 25, 29 KXBC3, 24, 25, 29 KXFL3, 25, 29 KXPA100, 29 KXPD3, 25, 29 LCD Test, 37 Low Battery Warning, 29, 42 Low-Pass Filter, 46 Memories, 17 Memory Label, 17 Menu Functions, 35 Menu Settings, 9, 29 Message Record/Play, 16 MH3, 25 Microcontroller Unit (MCU), 51 Microphone, 5 Microphone Gain Control, 14, 15 Microphone Settings, 30 Minimum Discernable Signal (MDS), 51 Mode Selection, 10, 37 Monitor and Sidetone Level Control, 12 Noise Blanker, 13 Noise
Transmit Settings, 14 Transverter, 21 Transverter Control, 41 Transverter Operation, 21 Troubleshooting, 42 Tune Power, 30, 40 Tuning Rate, VFO, 30, 40 TX EQ, 20, 40 TX LED, 25, 42 Universal Serial Bus (USB), 5 Variable Frequency Oscillator (VFO), 51 VFO B Parameter Displays, 11, 22 VFO Counts per Turn, 40 VFO lock, 11 VFO Setup, 30 VFO Tuning Controls, 11, 30, 40 Voice Modes, 15 VOX, Voice Modes, 14, 15, 30 Warranty, 53 Wattmeter, 41 XIT, 19, 40 56
