Elecraft K3S
firmware v5.66
Elecraft · Released Nov 28, 2018 · First seen Sep 14, 2026
Source:
elecraft.com
v5.66 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
Adds SWR read command to retrieve standing wave ratio data via remote control.
- New SW; command queries SWR readings in transmit and TUNE modes
Written from Elecraft's release notes, which are printed in full below.
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What's in this update
MCU 5.66 / DSP 2.88 / FPF 1.26
- ADDED SWR READ COMMAND: "SW;" returns the most recent SWR reading in transmit or TUNE mode, e.g. "SW023;" for an SWR of 2.3:1. Max value returned is "SW99;" (SWR = 99.9:1).
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