[Elecraft] ALC implementation

[Wes]

Analog ALC is a fully closed loop too. And Elecraft measuring the output and 
generating feedback isn't without flaw either. There is an ADC in that output 
measurement system that introduces low-level power jitter easily observed on a 
spectrum analyzer.

Wes  N7WS


On 6/28/2019 12:04 PM, Don Wilhelm wrote:
> Brian,
>
> ALC should never be used for power control doing so usually causes RF 
> compression and distortion.
>
> Many of the digital application instructions tell you to set for NO ALC as a 
> *maximum* audio level, set the power control for the maximum desired and then 
> reduce the audio level to reduce the power - I think that is why the slider in 
> WSJTX is labeled POWER when it is really an audio level control.
>
> The above method works fine for many transceivers, but NOT for Elecraft which 
> measures the actual power output, compares it with the set power and adjusts 
> the RF drive accordingly.  This is a fully closed loop system.  As far as I 
> know, Elecraft is the only amateur transceiver using that type of system.
>
> With Elecraft transceivers (except for the K2), adjust the audio drive level 
> to produce 4 bars solid on the ALC meter with the 5th bar flashing (this is 
> the NO ALC point.  Then leave it that way and adjust the desired power with 
> the power knob.  Doing otherwise will result in low power at the start and 
> power hunting as the transmission goes on.
>
> 73,
> Don W3FPR
>
> On 6/28/2019 2:38 PM, Brian Denley wrote:
>> I have always thought that ALC is not appropriate for power control.  It’s a 
>> protection system.  Over use of ALC acts like compression.  No?
>>
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