[Elecraft] KX3 ATU Modes

[Wayne Burdick]

On Sep 9, 2015, at 8:38 AM, "w7hd at msn.com" <w7hd at msn.com> wrote:

> My KX3 ATU is normally set to AUTO in the menu.
> Does this mean it will automatically tune without user action?

No. AUTO in the KX3 (or K3/K3S) means that the automatic antenna tuner is in-line rather than bypassed.

To tune, tap ATU TUNE. The SWR is displayed, and it should decrease as the algorithm progresses.

If the final SWR is higher than 2:1, you can tap ATU TUNE again within 5 seconds to initiate a broader search. This is useful with very narrow-banded antennas, or those that are electrically short or close to a multiple of a half-wave (very high-Z).

The ATU stores up to 32 LC network settings per band. These settings are not recalled as you move the VFO in RX mode, as that could be distracting. But they are recalled when you transmit, or when you do ATU TUNE, change antennas, do A/B VFO swap, etc.

You can clear all of the ATU LC memories on a given band by going in to the ATU menu entry and holding CLR (hold of the RIT/XIT offset control).

In CW mode, the rig tries to avoid interfering with your sending when the ATU requires retuning for a new transmit frequency. The first time you transmit in a segment that requires an LC network change, the firmware will wait for the first significant pause (letter space), then update the ATU. This is indicated by the ATU icon flashing a couple of times. It's possible that your first transmission will be at a somewhat higher SWR because of this behavior, but it has the advantage of not chopping off the first element due to ATU relay delays.

73,
Wayne
N6KR