[Elecraft] [KPA500] K3S/KPA500/KAT500 - Adjusting TX Power

[Joe Subich, W4TV]

 > So 5 to 7 bars seem to be indicated.  Where does the '4 solid, fifth
 > flashing come from'?

As explained by Wayne and Lyle several years ago, in data modes the
ALC meter scale is shifted so that any display below four bars shows
*audio input level* below the nominal operating point (whatever point
below the ALC clipping level Lyle set to allow headroom) while five
bars or more represents ALC action.

In data modes (DATA A, AFSK A), the DSP algorithm will *increase* the
audio gain (effectively increase the mic/line in level) as needed to
provide sufficient audio drive for the DSP to work correctly (generate
the nominal signal level prior to the ALC/Power setting routine).

73,

    ... Joe, W4TV


On 9/8/2017 5:35 PM, Wes Stewart wrote:
> I am often puzzled by some of this advice. The K3S manual on page 30 
> says among other things:
> 
> "While speaking into the microphone in a
> normal voice, adjust MIC for a peak ALC
> meter indication of about 5-7 bars (see below)".
> 
> Then regarding audio data modes it says on page 34:
> 
> "If you’re using an audio-shift transmit mode (LSB,
> USB, DATA A, or AFSK A), you’ll need to set
> the MIC level while watching the ALC meter.
> You can use the same procedure outlined for voice
> modes (pg. 30), except that speech compression
> should not be used."
> 
> So 5 to 7 bars seem to be indicated.  Where does the '4 solid, fifth 
> flashing come from'?
> 
> This is particularly questionable with constant amplitude modes, where 
> it doesn't matter whether there is ALC developed or not.
> 
> Maybe someone can enlighten me.
> 
> Wes  N7WS
> 
> 
> On 9/8/2017 5:36 AM, Don Wilhelm wrote:
>> Bret,
>>
>> This is a condition we call "Power Hunting", and it usually indicates 
>> that you do not have the audio level set correctly for Elecraft 
>> transceivers.
>>
>> Are you driving the audio to illuminate 4 bars on the K3S ALC meter 
>> with the 5th bar flashing?  You must operate Elecraft gear differently 
>> than other transceivers because of the closed loop system used for 
>> power control is different than the simplistic "control the drive 
>> level" system that other transceivers use.
>>
>> Ignore the internet (and WSJT-X) advice which tells you to adjust the 
>> power with the audio level and set the power to maximum.
>>
>> With Elecraft gear, set the audio as instructed in the manual and 
>> adjust the power with the POWER knob.
>>
>> 73,
>> Don W3FPR
> 
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