KX3 Software Page

KX3 Beta Firmware Revision

MCU 2.22 / DSP 1.30, 9-19-2014

Please read KX3 Beta Firmware Instructions for installing beta firmware.
Only the current production firmware releases can be downloaded by KX3 Utility automatically.

  • NOTE TO PX3 USERS: Please use PX3 rev. 1.08 or later firmware with KX3 rev. 2.22. This corrects a PX3 display-freeze issue when a KXPA100 is also present.
  • PA MODE (KXPA100) AUTO-OFF TIME CHANGED: The KX3’s PA MODE menu entry will revert from ON to OFF if the amplifier is not found within 8 seconds (was 4 seconds).
  •  CW-IN-SSB KEYING FIXED: When using an external keying device, the KX3 was returning to SSB mode too soon, truncating the CW waveform and causing key clicks.
  • UNEXPECTED KX3 RELAY SWITCHING WITH PX3 AND KXPA100 ATTACHED: The KX3 was occasionally misinterpreting a KXPA100 band-number poll as a band-change command. This has been corrected.
  • SPLIT/RIT/XIT SAVE: Now preserving SPLIT/RIT/XIT on band change and in memories. (2-m note: SPLIT can be used to set up odd repeater splits in VFO A and B.)
  • PA MODE TURNS OFF AUTOMATICALLY IF NO KXPA100 FOUND: If you set the PA MODE menu entry to ON, but no KXPA100 is connected, the menu entry will be set back to OFF. This corrects a problem where some users had PA MODE set to ON unintentionally, losing their internal ATU setup (KXAT3).
  • PX3 USED WITH KX3 ON 2 or 4 METERS DISABLES “SLEEP”: If a PX3 is connected and turned on, SLEEP mode (2 and 4-meter FM battery save) is automatically disabled to prevent the spectrum display from shifting down during SLEEP cycles.

Misc. bug fixes:

  • PX3 DISPLAY UPDATED WHEN REV SWITCH USED: REV changes only VFO A on the PX3, just as it only changes VFO A on the KX3 display.
  • MORSE-CODE SWITCH TONES FIXED ON 2 and 4 METERS: USB and LSB (‘U’ and ‘L’) were reversed. Frequency readout had decimal in the wrong location.
  • 60-METER UPPER BAND LIMIT (U.S.) CORRECTED: Now accommodates DATA and CW mode operation on the highest-frequency channel.
  • SCROLLING VFO B INFO MESSAGES FIXED: Informational messages that use “Times Square” scrolling format now work even when a special VFO B display or text decode is in use. (Example: The “USE PHONES” reminder when turning on DUAL RX.)


KX3 Production Firmware Revision

MCU 2.19 / DSP 1.30, 9-04-2014

See KX3 Firmware Release Notes for a complete revision history.
This release can be automatically downloaded by KX3 Utility.

 New Features:

  • PX3 SUPPORT: On a band change, the first command sent by the KX3 to the PX3 is “BN” (band number) to ensure correct handling of subsequent commands.
  • 2-M DIRECT FREQUENCY ENTRY FROM OTHER BANDS: Range is 120-168 MHz. Note: Sensitivity falls off as you move out of the 144-148 MHz range.
  • 2-M TRANSMIT LIMITS: Normally, 2-meter transmit is limited to 144-148 MHz. This can be increased to 141-151 MHz for MARS use. The range can also be limited to 144-146 MHz for KX3 owners outside the U.S. (see separate instruction sheet).
  • 2M/4M ANT. JACK PROVIDES OPTIONAL +5VDC DURING TRANSMIT: Many high-band transverters and other gear can use a DC voltage of 3-12 V on the center conductor of the antenna coax to provide T/R switching or other functions. The KX3-2M/-4M module can now place +5VDC (+/- 0.3 V) on the antenna jack if desired. To turn this feature on/off, locate the 2M/4M menu entry and tap 2 (ATTN switch). The parameter will be either TXant 5V- (off) or TXant 5V+ (on). ant is displayed as a small antenna symbol.

             Bug fixes:

  •  PL TONE FM DEVIATION ERROR: The PL tone deviation displayed in the menu was about 40% lower than the actual deviation value in effect. Because of this, repeater users should re-check their PL deviation setting. To do this, locate the FM DEV menu entry, then tap 1 to switch to PL DEV. Set the value to 0.35 (kHz) the new default unless some other value is applicable.
  • CW-IN-SSB IMPROVEMENT: The operators specified CW QSK delay is now used during CW-in-SSB, even with external CW keying. (This was already working with the internal keyer.)
  •  CW TIMING BUG FROM REV 1.95 CORRECTED: Element lengths with the internal keyer were slightly too short due to a calculation error.
  • KXPA100 AUTO POWER-ON WITH PX3: If a PX3 and KXPA100 are both in the system, KXPA100 automatic power-on will now work even if the PX3 is turned on first. (Note that at present there is no way to do automatic power-on of the PX3 itself.)
  •  INCREASE IN ALLOWED TX CURRENT: Allows full-power output on some bands where previously a drop to 5 watts had been observed (with an external 12-14 V supply).
  •  KX3-2M BAND-CHANGE FIX: With SLEEP enabled, a band change from 2 meters to any other band was causing the 2-m module to be left powered up


KX3 Archived Firmware Revisions

Please browse our KX3 Firmware Archive FTP Folder for obtaining archived KX3 firmware revisions.
Only the current production firmware releases can be downloaded by KX3 Utility automatically.


KX3 Utility and Drivers for Windows, Mac and Linux

Elecraft KXUSB Cable for the KX3

Elecraft offers the KXUSB cable for USB only computers etc.  It uses the FTDI chip set.

Before plugging in this cable to any of your computer's USB ports, you may need to install the correct FTDI USB drivers for your computer's operating system.   Drivers are available for most Windows, Mac, and Linux OS's.  Note that most of the latest Windows 7 operating systems already have the proper drivers for the FTDI chip set and will automatically install them if you just plug the KXUSB cable into a USB port.

Connecting the KX3 to a Computer

If your computer has a standard serial port, all you will need is our KXSER cable for the KX3. .

Most modern computers no longer have serial ports but instead use USB (Universal Serial Bus) ports for connecting to external devices. Elecraft provides the KXUSB cable to connect the KX3 to these computers.

KX3 Utility Download


KX3 Tools and Application Notes