Posted by
Joe Subich, W4TV-4 on
Mar 03, 2012; 3:20pm
URL: http://elecraft.85.s1.nabble.com/Kx3-power-output-tp7338175p7340067.html
> Set the drive level for the appropriate ALC meter response, and then
> set the output power level where you want it.
But remember that PSK31 has an approximately 3 dB crest factor (peak
to average ratio). To prevent the K3 and presumably KX3 amplifiers
from saturating and generating a very wide signal, the maximum power
in PSK31 should be between 40 and 50% of the maximum available. With
the K3 power control set for 40 to 50 watts, instantaneous PEP output
will be 100 to 110 W even though the typical PEP reading wattmeter may
only show 45 W.
73,
... Joe, W4TV
On 3/3/2012 9:58 AM, Bruce Beford wrote:
> Rich is absolutely right on this. Also, since the original question was
> regarding the KX3, I expect the KX3 to behave the same way. Set the drive
> level for the appropriate ALC meter response, and then set the output power
> level where you want it.
>
> 73,
> Bruce, N1RX
>
>> 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
>
>
>
>
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