[Elecraft] OT: Windows 7 AGC on Input

[Rick Bates, WA6NHC]

From my saved email files... it may help/apply.

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Found this article posted on the Yahoo Groups Ten-Tec Omni VII group today:  https://www.reddit.com/r/amateurradio/comments/3eytah/huge_windows_bug_ruining_your_receive_performance/
 
The article discusses a Windows Vista and later versions bug when interfacing with an audio device utilizing the Texas Instruments PCM2900 series PCM2904 and below, pre-C revisions device.  The article also shows a permanent (software configuration change) fix for the bug.
 
The article states that all Signalink USB digital mode interfaces are affected by this bug.
 
Knowing that some of you are using the Signalink USB, I’m sending you this info in case you were not already aware of it.
 
Some of you may have rigs with a direct computer interface for digital mode operation.  Your rig may use the affected TI device.  If so, you are also affected.
 
In my case, I use the Signalink USB.  When I first installed it, I noted I had to run the Signalink’s RX gain and Codec gain controls very low to get good levels to the computer.  As a result, I added a 10:3510 or -51db (voltage) divider on the Signalink’s input (mounted on the rig programming socket inside the unit).  Now I know why that was required – the bug in Windows for the audio device being used.  With the bug fix from the article, I have now reverted back to not using the voltage divider.  Hopefully, levels are now above noise floor values and results will be better.  I’ve also downloaded and installed the digital level meter applet the author mentioned.  It is available at http://www.darkwooddesigns.co.uk/pc2/meters.html, about 1/3 down in the page.
 
Hope you find this article useful.
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Rick, WA6NHC

iPad = small keypad = typos = sorry ;-)

> On Oct 4, 2015, at 8:39 AM, David Cole <dave at nk7z.net> wrote:
> 
> Hello,
> 
> I am trying to solve a slight digital problem, using my K3.  I suspect
> that Windows 7 has an AGC of some type on it controlling the Line Input
> levels.
> 
> Can someone verify if this is true, and if so, is there a way to disable
> the AGC on input?
> 
> -- 
> Thanks and 73's,
> For equipment, and software setups and reviews see:
> www.nk7z.net
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