[hpsdr] WSJT VAC, ALC and PowerSDR mRX PS

[Ken N9VV (Win-7/64)]

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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