[Elecraft] ALC implementation

[Richard Corfield]

That's interesting thanks. It means that by aiming for no ALC indication
I've been under modulating.

I assume the input stage in the KX3 can take higher levels?

On Fri, 28 Jun 2019, 16:35 Bob McGraw K4TAX, <rmcgraw at blomand.net> wrote:

> Well written generic paper for operation of FT-8 and other digital
> signals of like mode.   It does not totally nor correctly apply to
> Elecraft radios as power management is handled by a totally different
> means.   And those means and methods suggested in this paper are not
> applicable to Elecraft radios for power control.   From experience in
> set-up and operating different radios and different interfaces, I do
> believe that the WSJT-X operating panel which shows the right slider
> labeled PWR is very misleading and should be changed to some other
> description i.e. TX AUD.
>
> While many radios use the control of audio level to adjust power output,
> this is somewhat misleading as there are control areas available such as
> SPKR level in Windows, and Line Gain for the radios or perhaps an
> external sound card device.   Again, the use of the acronym MIC is
> always a frighting term,  in as much as many systems produce a transmit
> audio level that will overdrive the microphone pre-amplifier input.
> Once this occurs, reducing MIC gain will not relieve the distorted audio
> as it occurs pre level control in the circuit.   Frankly, one should not
> connect the sound card to a microphone input without proper and correct
> means of attenuating the signal before it is connected to the microphone
> input.   In addition, this will always preserve the transmit
> Signal-to-Noise ratio.
>
> As to "compression" I take that to mean Speech Processing, which should
> ALWAYS be off or set to a zero value.   Likewise for EQ, again always
> set to OFF or FLAT  for transmit and receive purposes as well.
>
> As a mater of practice, there are three or perhaps four distinct places
> that audio levels can be controlled in the transmit path. First is SPKR
> level which is the audio level out of the computer. Second is the WSJT-X
> PWR slider, and third is the Line Gain within the radio.  A fourth, if
> used, would be an external interface such as a Signalink or
> Soundblaster.   If any of these points end up near minimum value or near
> maximum value, I strongly suggest further investigation as to why and
> remedial steps taken to more "normalize" the control values at all
> points in the system.
>
> Some radios do have "meter" indicators which relate to ALC levels while
> others simply prove a visual means usually the illumination of a LED.
> In all cases, the indicators should be observed, and the radio operated
> accordingly with NO indicated ALC action occurring.    Again, regarding
> Elecraft radios, the first 4 bars on the "ALC Scale" are audio level and
> NOT ALC action.  The onset of actual ALC occurs at the 5th bar and higher.
>
> 73
>
> Bob, K4TAX
>
>
>
>
> On 6/28/2019 9:18 AM, Andy Durbin wrote:
> > Does anyone know of any rig that uses "compression" rather than linear
> gain control to implement ALC?
> >
> > ref - https://www.dropbox.com/s/f4uaop5tqwzaweu/FT8Noise6.docx?dl=1
> >
> > 73,
> > Andy, k3wyc
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