http://elecraft.85.s1.nabble.com/K3-Odd-ALC-behavior-tp7633052p7633128.html
in Windows 10. I may be missing something in the search, but if you have
more details. I looked carefully through wdma_usb.inf and I can't see
anything obvious. From windows 10 in my case.
>
> On 8/5/2017 11:14 AM, Wes Stewart wrote:
>
>> But IMHO, you need to put a 30 dB attenuator on the input of the internal
>> sound card; it is way too sensitive. I'm having to run the Windows gain at
>> less than 5% and Line In at 10 or less.
>>
>
> Actually, you need to adjust the options in the Windows *.inf file
> used for the PCM-series CODEC (or use the codec that identifies as
> line level). Windows is turning on a 20 dB preamp in the CODEC.
>
> I suspect if one sets the Windows Sound Options (Control Panel) to
> display dB rather than percentage, the minimum level will be some-
> thing like 16 to 20 dB! That indicated the fixed 20 dB "mic preamp"
> is engaged.
>
> 73,
>
> ... Joe, W4TV
>
>
> On 8/5/2017 11:14 AM, Wes Stewart wrote:
>
>> Wayne,
>>
>> There are no beat notes. These frequencies, at least from the FT8 program
>> in Tune mode are single frequency. Based upon output RF spectrum
>> measurements*, with for example 1010 Hz input and 4-5 bars of ALC, I see
>> spurious or intermodulation sidebands, down -65 dBc. If I change nothing
>> else but adjust the tone frequency to 1000 Hz the spectrum is the same but
>> the ALC bars are cyclic, going from none to 4-5, at about the 2 HZ rate
>> Brian reported earlier. (Slow ALC in action?) That's the good news.
>>
>> If I set the tone to 1500 Hz, the FT8 mid-band target, I'm presented with
>> the cyclic ALC and some ~193 Hz, -50 dBc sidebands.
>>
>> I have tried this with both the K3S internal sound card and via Line
>> In/Out into my laptop sound card. The results are more-or-less the same.
>> But IMHO, you need to put a 30 dB attenuator on the input of the internal
>> sound card; it is way too sensitive. I'm having to run the Windows gain at
>> less than 5% and Line In at 10 or less.
>>
>> I would suggest that you do some measurements with a low-distortion sine
>> wave audio source run into the radio to eliminate the possibility that this
>> junk is a result of all of the digitally generated tones.
>>
>> If this (what I will call a) problem continues to exist then I think a
>> fix is in order. Expecting users to select particular frequencies to use
>> to set gain levels isn't an acceptable workaround.
>>
>> Regards,
>>
>> Wes N7WS
>>
>>
>> * My "spectrum analyzer" is my SDR-IQ which I have used to measure TX IMD
>> on both my K3 and K3S. Your IMD
>> measurements on my K3S concurred with mine within 1 dB or less.
>>
>> On 8/4/2017 4:45 PM, Wayne Burdick wrote:
>>
>>> Is it possible that a beat note between tones (and their harmonics) is
>>> what’s modulating the ALC reading? If so, moving the tone slightly off the
>>> standard pitch may be an acceptable workaround.
>>>
>>> Wayne
>>> N6KR
>>>
>>>
>>> On Aug 4, 2017, at 1:42 PM, Wes Stewart<
[hidden email]> wrote:
>>>>
>>>> Good find Brian!!! I see it too in FT8.
>>>>
>>>> This probably explains the great variability in results reported. Some
>>>> of us have a problem, others say, Huh, what the heck are you talking about?
>>>>
>>>> Wes, N7WS
>>>>
>>>>
>>>> On 8/4/2017 11:33 AM, Brian Hunt wrote:
>>>>
>>>>> Here's some followup:
>>>>> FLDIGI shows the "pumping" affect with carrier tones of 500, 1000,
>>>>> 1500, and 2000 Hz.
>>>>> WSJT-X 1.8 shows the "pumping" affect with carrier tones of 1000, 1500
>>>>> and 2000 Hz (couldn't select 500 Hz).
>>>>>
>>>>> The affect is very narrow with frequency. 10 Hz either way and the
>>>>> output and ALC display and MON output is rock solid. Changing the K3
>>>>> filter center frequency has no effect on the above.
>>>>>
>>>>> 73,
>>>>> Brian, K0DTJ
>>>>>
>>>>> On 8/4/2017 10:58, Brian Hunt wrote:
>>>>>
>>>>>> I spent some quality time with my K3, FLDIGI and an oscilloscope
>>>>>> today. I had the same problem as described. Looking at my USB soundcard
>>>>>> output to the K3, the amplitude of the audio from FLDIGI in TUNE mode was
>>>>>> rock solid. Looking at the MON output from the K3, the level oscillated in
>>>>>> time with the ALC "pumping" at about 2.4 Hz (timed with a stop watch). At
>>>>>> the same time the K3 power output into a dummy load was rock solid at a
>>>>>> selected 10 watts.
>>>>>>
>>>>>> Then I changed the carrier frequency in FLDIGI slightly off 1500 Hz
>>>>>> and the "pumping" went away! At 1515 Hz I could easily set the ALC to the
>>>>>> desired 4 bars solid, 5th flickering. Then I remembered (and verified)
>>>>>> that the default filter center in DATA A mode is 1500 Hz. I changed the
>>>>>> filter center frequency to 1450 Hz and moved the FLDIGI frequency around
>>>>>> but couldn't reproduce the "pumping".
>>>>>>
>>>>>> I plan to repeat the same tests with WSJT-X 1.8 but wanted to get
>>>>>> this out to the group.
>>>>>>
>>>>>> 73,
>>>>>> Brian, K0DTJ
>>>>>>
>>>>>>
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