Elecraft K3S
firmware v2.73
Elecraft · Released Dec 9, 2008 · First seen Sep 14, 2026
Source:
elecraft.com
v2.73 is not the latest firmware for the Elecraft K3S: the current version is v5.67 (January 22, 2019). Go to v5.67
In short — summary by updatemystuff.com
RX EQ applies to both receivers, tune no longer cancels auto-notch, and ADC calibration menu added.
- RX EQ applied to main and sub receivers
- Tune no longer cancels auto-notch
- ADC reference calibration menu entry added
Written from Elecraft's release notes, which are printed in full below.
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What's in this update
MCU 2.73 / DSP 1.98
- RX EQ is now applied to both main and sub receivers.
- TUNE NO LONGER CANCELS AUTO-NOTCH.
- CONFIG: ADC REF MENU ENTRY: This allows the operator to calibrate the voltage reference used by the K3 to measure and display certain values, such as the rigs supply voltage. ADC REF calibration is optional but recommended. First, disconnect anything attached to the ACC jack. Next, locate the CONFIG: ADC REF menu entry. It will initially show 5.00 volts as the reference voltage. Using a DMM set to DC volts, measure the actual voltage at pin 2 of the ACC jack. This must be done while the ADC REF parameter is being displayed. (The (-) probe of the DMM should go to the K3s chassis ground, e.g. at the GROUND lug.) Finally, use VFO A to set the ADC REF menu parameter to what you measure at pin 2.
For software developers:
- ÒCPÓ COMMAND ADDED (speech compression setting).
- Auto-report (AI2 mode) added for the ÒMGÓ command (mic gain).
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