Elecraft K3S
firmware v4.66
Elecraft · Released Mar 22, 2013 · First seen Sep 14, 2026
Source:
elecraft.com
v4.66 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
FSK-D keying bandwidth greatly reduced for cleaner signals; K3/0 remote-rig fixes.
- FSK-D sideband amplitude reduced 25-30 dB
- K3/0 minimum supply voltage reduced to 7.6 V
- K3/0 VFO lock and TX LED sync corrected
Written from Elecraft's release notes, which are printed in full below.
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What's in this update
MCU 4.66 / DSP 2.81
- FSK-D KEYING BANDWIDTH GREATLY REDUCED: This change reduces the amplitude of the FSK-D keying sidebands by 25-30 dB at a 500-Hz offset, giving the K3 one of the cleanest FSK signals available.
- K3/0 (REMOTE-RIG) IMPROVEMENTS: (1) Supply voltage can go down to 7.6 V; (2) VFO lock works correctly; (3) TX LED no longer gets out of sync.
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