[Elecraft] Kx3 power output

[Don Wilhelm]

I would like to amplify what Rich is saying:
With the K2, or K3 and I assume also the KX3, set the desired power 
level with the power control and adjust the audio to fully drive the 
radio just to the point of onset of ALC.

The proper audio level is determined by the ALC meter.  With the K2, 
increase the audio until you see 1 ALC bar and then back off until it 
goes out.
With the K3 (and probably also the KX3) adjust for 4 ALC bars solid and 
the 5th bar flickering.
The first 4 bars of the K3 ALC meter are not actually an indication of 
ALC - they are more akin to a VU meter.  The onset of ALC is at the 5th bar.

If you attempt to operate the K2 or K3 (and likely the KX3) using the 
methods typically stated for other transceivers, they will "power hunt" 
trying to produce the power set on the Power knob, but will be 
"confused" because there is not enough audio to produce the requested 
amount of power.

I cannot emphasize this point enough - the way the K2 and K3 control 
power is different than that typically used by other transceivers.

73,
Don W3FPR

On 3/3/2012 9:52 AM, Richard Ferch wrote:
> Chip,
>
> While this method of control for PSK31 (set power to maximum and use
> audio drive controls to adjust output) works well with many rigs, it
> does not work with the K3. If the ALC meter is showing fewer than 4
> bars, output power will be unstable, and if the power control is set to
> maximum, the K3 will do its best to achieve that power level, which is
> not what you want.
>
> With the K3 in DATA A (or AFSK A), the recommended procedure is to set
> the audio drive at the level that results in 4-5 bars on the K3's ALC
> meter, and then use the PWR control to adjust the output power. You can
> think of the 4-5 bar point on the K3's ALC meter as the point where ALC
> is just starting to activate.
>
> With the K3 in PSK D mode, neither of these methods is possible. In PSK
> D there is no audio drive to adjust; the only control available is the
> PWR control.
>
> 73,
> Rich VE3KI
>
>
> Chip Stratton wrote:
>
>> I think the usual preferred method for getting maximum PSK power
>> output is to set your transmitter for its maximum potential power
>> output, but adjust PSK modulation to a point below which ALC
>> activation (and hence signal peak clipping) is not occurring. As Rich
>> says, this typically will be at an average power output of one half
>> what the transmitter is capable of delivering in CW or RTTY mode. An
>> PSK IMD meter would be ideal, but using this method seems to work
>> fine. I do not have a K3, but with my IC-7000 I use this method,
>> though usually setting modulation levels such that average power
>> output is in the 20 to 40 watt range if I'm trying to reach a
>> difficult station.
>>
>> Perhaps the adjustments on the K3 and KX3 are different if using
>> built-in PSK modulation?
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