KX3 Software Page

KX3 Beta Firmware Revision

MCU 2.18 / DSP 1.30, 8-26-2014

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

             New Features:

  • 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 Production Firmware Revision

MCU 2.12 / DSP 1.30, 7-11-2014

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

  • 40-METER TRANSMIT IMPROVEMENT: The 40-m band-pass filter was being bypassed in transmit mode, due to a change in rev. 1.94 that allowed MARS operation from 8.5-9 MHz. This resulted in reduced suppression of narrowband 40-meter transmit images, most notably in FSK-D mode. (The low-pass filter setting was correct, though, which made this error hard to detect. Wideband spurious suppression specs were met.)
  • FAST MESSAGE PLAY: A long-hold of MSG (~3 sec) puts the KX3 into FAST PLAY mode. In this mode, the BAND+, BAND-, and FREQ_ENT switches can be used to play/repeat messages 1, 2, and 3 immediately, without the need to first tap MSG. To turn off fast play, hold MSG for ~3 seconds again, or turn the KX3 off and back on. Notes: (1) In voice modes (using the built-in DVR), only messages 1 and 2 are available, corresponding to BAND+ and BAND- in fast-play. (2) At present, message chaining is only available in CW modes (with both normal and fast-play).
  • KX3-4M POWER CONTROL: Scaled drive level to match slightly higher gain of 4-meter unit vs. 2 meters.
  • KX3-to-KXPA100 SERIAL COMMUNICATIONS IMPROVED: Added better syntax checking.
  • MORE ACCUTATE KXPA100 “TUNE” POWER OUTPUT (PA ALC): More accurate control of the KXPA100’s power output during TUNE from the KX3 (PA ALC) now applies up to 70 W (60 W on 6 meters). Above this point, KXPA100 drive is still estimated based on the 75-W factory calibration. This prevents accidental overdrive in conditions sometimes found during full-power portable or mobile operation, such as high SWR, high current, etc. NOTES: (1) To disable PA ALC, locate MENU:PA MODE, then tap ‘1’ (PRE) until you see “PA ALC-”. (2) PA ALC only applies during TUNE, not during normal transmit. Also, if you change bands or adjust PWR, and want to fine-tune the KXPA100’s power output again, you’ll need to do another TUNE. (3) PA ALC does not apply if TUN PWR is in effect, since its limit is 10 W, bypassing the amp.
  • KXPA100 TRANSIENT FAULT DISPLAY: Common KXPA100 faults requiring operator notification, such as high SWR, are always reported on the KX3’s display. Transient faults such as serial port errors are normally not displayed, since they rarely impact operation. For diagnostic purposes, such faults can now be displayed as “FAULT nnn” where nnn is a 3-digit number originating from the KXPA100. To enable this mode, go into the KX3’s PA MODE menu entry and tap ‘6’ (DLY) until you see “XFAULT+”.


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