[hpsdr] WSJT VAC, ALC and PowerSDR mRX PS

[John Laur]

Conrad,

Happy to have helped. Sounds like you have done everything else right.

73, John KF5SAB

On Sat, Oct 11, 2014 at 9:14 PM, Conrad Farlow <conrad at g0ruz.com> wrote:

> ***** High Performance Software Defined Radio Discussion List *****
>
> 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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