[Elecraft] SSB Overshoot

[Jack Smith]

Yes indeed. One should not depend on ALC to set output power.


Jack

Don Wilhelm wrote:
> Jack,
>
> Those displays look quite similar to what I would have expected - overshoot
> will occur if the audio is increased sufficiently to activate the ALC.
>
> The displays do point out the necessity of not driving the K2 into ALC if
> overshoot is to be avoided - for digital modes, that means to increase the
> requested power to well above the intended operating power and limit the
> drive using the mic input level.
>
> Of course, the same thing applies to most any other transceiver if the IMD
> is to be kept at a minimum - the thing unique about the K2 is that the
> control of the power output level is also involved.
>
> I always have bad feelings about attempts to use ALC as a power output
> limit - expecially on SSB because it only leads to distortion.  It is a form
> of compression, but audio compression is much better at increasing the
> average power of a signal.  One could design a compressor that works at RF,
> but it would be quite different than the ALC found in most transceivers.
>
> 73,
> Don W3FPR
>
>   
>> -----Original Message-----
>>
>> I've made a quick series of measurements at 7 MHz, 50 watts output and
>> varying audio drive levels and posted the result in a PDF file that may
>> be viewed at
>> http://www.cliftonlaboratories.com/Documents/SSB%20Burst%20Analysi
>> s%20Elecraft%20K2.pdf
>>
>> Jack K8ZOA
>> K2: 5689
>> www.cliftonlaboratories.com
>>
>>     
>
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