[Elecraft] ALC for Digi, One Last Check Please

[Kevin, N4TT]

Bob:

You nailed it again. 1500 Hz is where I normally set my audio so when I do
my quick test before operating this pulsating is what I see.

I went to 1700 Hz (and a few others) and ran the same tests. It was steady
as a rock in tune and exactly as expected in transmit (4+1 blinking).

Sometimes things looked real good. Sometimes they looked strange
(pulsating). I always felt there was something intermittent but now I know.
The issue is simply where I chose to test. I'd have never figured that out.

Thanks and 73!
Kev N4TT



On Tue, Jun 25, 2019 at 4:17 PM Bob McGraw K4TAX <rmcgraw at blomand.net>
wrote:

> The pulsating is the result of the refresh rate of the display and the
> 1500 Hz tone.  Change the TUNE tone to a non- 500 Hz interval such as
> 1250 Hz. or 1700 HZ as such.   Yes, in FLDIGI the TUNE tone is a single
> frequency you have selected on the waterfall scale or in the box at the
> bottom of the screen.
>
> When you setup and adjust the audio levels, the radio mode must be DATA
> A for PSK-31.  The audio level for correct ALC indication should show 4
> bars solid with the 5th bar flashing.  The Elecraft radios DO NOT
> operate like other brands in regards to the ALC indications.   The
> actual ALC in the Elecraft starts at and after the 5th bar on the ALC
> scale.   Before that the "audio level" is indicated.    Then set the PWR
> knob on the radio for the power output you desire.   DO NOT adjust the
> audio level to change power.
>
> There are 3 places where audio level is controlled and each one needs to
> be correct.  First is the SPKR level out of the computer.  This should
> be about 30%  {-18 dB} or so.  Then output attenuation on the lower
> right of FLDIGI which should be about -10 dB to -15 dB .  Then the Line
> Gain on the radio {adjusts by the MIC knob} to about 30.   These are
> "ball park" numbers and should get you up and running with a clean
> signal.   If any one or more is near minimum or near maximum, you need
> to investigate further.
>
> If needed I can send screen captures.
>
> 73
>
> Bob, K4TAX
>
>
> On 6/25/2019 2:42 PM, Kevin, N4TT wrote:
> > I've made a few PSK-31 contacts on the K3s and I've not gotten any bad
> > reports. However, I'm still a little concerned about what I see for ALC.
> >
> >
> > The video below (no audio) shows the ALC meter responding first to a
> "TUNE"
> > command from fldigi. This sounds like a pure tone in the headphones but
> the
> > ALC meter responds oddly, almost like it is pulsating. I expected ALC to
> > pretty much be steady.
> >
> > Next in the video is just clicking T/R in fldigi with no typing. It
> sounds
> > as expected in the headphones (a trilling sound). The ALC response looks
> > better but I can still see the pulsations in there. I expected to see 4
> > bars solid and the 5th flashing.
> >
> > https://photos.app.goo.gl/4AaLaVu1r8UDv5LT9
> >
> > Am I reading too much into this? Is this how your K3s responds?
> >
> > I'm using the K3s sound card. Level in Windows is -14.7 dB. Level in
> fldigi
> > is -12.7 dB. The level control on the K3s is set for 18.
> >
> > 73,
> > Kev N4TT
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