[hpsdr] WSJT VAC, ALC and PowerSDR mRX PS

[Conrad Farlow]

No Ken, that would have got some comments with the amount of MS 
operating I do.

As for the compressor, leveller and TX EQ that is all disabled when on 
DIGI  modes. I have been having great success with this set up. The 
ANAN-10 works very well as a transverter driver. Problem solved. I also 
have made sure that there are no non integer sample rate conversions 
(other than the wsjt native one) and the TX spectrum is excellent at 
-46dBC 3rd Order without PS. The driver is 12dB below the 1dB 
compression point an the PA is 8dB below.

Should keep the neighbours happy.

73

Conrad G0RUZ

> ***** High Performance Software Defined Radio Discussion List *****
>
> If VAC is not a registered copy, it will generate a female voice 
> asking you to register the product ($39). The voice comes on at 
> unscheduled times. Could this be the source of the "noise burst"?
>
> GL de Ken N9VV
>
> On 10/11/2014 7:19 PM, Warren C. Pratt wrote:
>> ***** High Performance Software Defined Radio Discussion List *****
>>
>> Hi Conrad,
>>
>> I don't know about the noise burst.  However, I can comment on the way
>> the ALC works.
>>
>> First, and perhaps most important for your concern, the ALC NEVER
>> applies any gain greater than 1.0.  If merely sits on the sideline
>> watching the incoming signal and, if/when it sees a signal coming on the
>> horizon that is too large, it gradually reduces the gain so the signal
>> peaks at 1.0.  Once the peak has passed, it gradually increases the gain
>> back to 1.0 (unless, of course, there's another peak coming that
>> requires gain reduction).  Also, there is zero "ALC overshoot" in this
>> system.  There is no option to disable the ALC; however, as I described,
>> it just sits on the sideline and watches unless there is an
>> over-amplitude signal on the horizon.
>>
>> That said, there are a few features that DO offer greater than unity
>> gain:  Compressor, Leveler, and Equalizer.  Those can all be deactivated
>> and I suppose they should be for digital modes.
>>
>> I doubt that this solves your problem; however, perhaps it might offer
>> other ideas of what could be generating this noise burst.
>>
>> 73,
>> Warren  NR0V
>>
>> On 10/11/2014 2:07 PM, Conrad Farlow wrote:
>>> ***** High Performance Software Defined Radio Discussion List *****
>>>
>>> I am using an ANAN-10 with the latest version of PowerSDR mRx PS. I
>>> have VAC working well with WSJT but I get a burst of noise just before
>>> WSJT starts generating audio. It is 20dB below the modulated audio and
>>> I suspect that is due to some kind of expander action on the ALC. I am
>>> driving a transverter and have only 500mW output to do so. My TX is
>>> very clean but is there any way of getting rid of this, in fact
>>> turning the TX ALC off altogether? I don't need it as the audio level
>>> is tightly controlled and I have a the TX gain set at around 75dB.
>>> There is no way that I am going to overdrive anything.
>>
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