[Elecraft] KXPA100 Utility v1.14.11 CONFUSION and HELP!

[Dick Dievendorff]

Good morning, Dave!

PA bypass is controlled by the KX3 power setting and ATU tune. If you have selected a power level below 10 watts with the KX3 power control, the KX3 bypasses the amp.  The PA is also bypassed during ATU tuning. If you don't have the KX3 in PA mode ON and the ATU is not tuning, the PA should initialize in "not bypassed" at power on. In PA mode the KX3 power control should go up to 100 watts or so. 

Pressing the ATU tune button causes the KXPA100 to begin tuning.  It blinks the 25w to indicate tuning in progress.  But now it needs a few watts of steady RF to measure SWR.  You need to turn on the transmitter at this point.  The amp TUNE button is intended mostly for transceivers other than the KX3.  With the KX3, with PA mode on, the KX3 sends a command that effectively presses the KXPA100 TUNE button, then the KX3 turns on its transmitter, and the ATU steps through relay settings.  The KX3 periodically asks the amp if it is done tuning, and when it is, the KX3 stops sending carrier.  If you don't have a KX3, or choose not to use the connecting cable or PA mode is not ON, then you'll need to somehow key the transmitter to provide a few watts until ATU tune completes.

The ATU is bypassed if the match is good enough without the ATU.  If you tune into a dummy load, often the best setting is "ATU bypassed".  My 20 meter antenna offers a very low SWR in the low end.  But in the phone band the SWR rises.  I have tuned at several places in the band.  At the low end, the best tuning solution is bypassed, and that tuning solution is memorized so when I return there it selects that setting, in mode MAN, based on a frequency count.  In the phone band, the tuning solution uses tuner reactances to show the amp a low SWR.

After you have tuned the ATU in several places in the band, I'd recommend you switch the ATU to mode MAN.

73 de Dick, K6KR



> On Jun 29, 2014, at 2:36, Esquer Dave <dave.esquer at gmail.com> wrote:
> 
> New KXPA100 (with 100w internal ATU) for KX3 owner. I have the KX3 and KXPA100 hooked up with the Elecraft supplied cables.
> 
> In the Amplifier section of the utility, when using the KXPA utility, why is the PA Bypass box checked? I understand the Attenuator box being unchecked.
> 
> In the Anntenna Tuner section, the Tune button (on the right) does not tune the rig, it just causes the 25w LED to blink. No noise is heard from the ATU. I have to physically hit the ATU tune button on the KX3 to retune.
> 
> Finally, in the same Antenna Tuner section, why is the ATU Bypassed check box (below the Mode options) checked when the Mode box is set to Auto?
> 
> I’m doing something wrong, please help this newbie.
> Dave, K6WDE
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