Anan G2 and Thetis VAC overflow/underflow help

[vk2qv]

Hi Team

I'm fairly new to both this group and to using G2. I've been running into an issue with VAC overflow and underflow on both the input and output sides. As a result, I'm losing data packets in FT8 mode, which is impacting both transmit and receive performance.
Please see the attached image for reference. After resetting the values to zero, I’ve noticed that as soon as the transmit cycle completes, the overflow and underflow counts begin to rise again. I'm not sure what's causing this or how to resolve it.
I'm currently using the latest version of the Thetis application.

Software:
Thetis v2.10.3.11 x64
VoiuceMeter Potato
vspManager (virtual com ports)

Photo link: https://photos.app.goo.gl/thvpzSzAK4TyEHrq8

Thanks in advance for any advice or suggestions to help resolve this issue.

73,
Ras – VK2QV

[w-u-2-o]

Ras,

First and foremost, make certain that you have gone into the old Windows Sound Control Panel, this one here:

Capture.JPG (119.88 KiB) Viewed 56 times

Drill down into all of the Voicemeeter related devices and change their properties to 48KHz sample rate. 16 or 24 bits doesn't matter. Then restart Voicemeeter.

If that doesn't work by itself, and you do not have an ASIO-capable sound card or interface as part of your system, then try changing back to MME drivers as sometimes Voicemeeter is not stable when using ASIO by itself. Normally it wants/needs a real bit of ASIO sound hardware assigned as output A1.

Another thing to try is to increase the VAC main buffer size to maximum. You don't need the speed of ASIO or a small buffer size with 99% of the digi modes out there. It only comes in handy for phone and certain ARQ modes like VARA.

73,

Scott

P.S. you can easily place images and photos in your posts by dragging and dropping them into the edit window, then using the "place inline" button.

[vk2qv]

Hi Scott

Thanks for the reply. I can confirm all audio properties are set to a 48kHz sample rate and 24-bit depth.

I’ve identified when VAC1 overflow and underflow values begin to rise—they occur if I mute the microphone or disable M1 while operating in FT8 mode. Otherwise, ambient room noise is captured by the mic and mixed into the FT8 transmit signal, as shown in the G2 waterfall (marked in red). Following that, at the end of the transmission cycle, VAC1 OF/UF values increase, resulting in degraded FT8 decoding.

VAC1 error when Mute or B1 turned off.png (1.45 MiB) Viewed 21 times

Once M1 disables or mutes the mic, the OF/UF values begin to increase. But as you see transmitted signal is clean.

VAC1 error when Mute or B1 turned off1.png (1.34 MiB) Viewed 19 times

Your suggestions would have been most welcome.

Cheers, Ras VK2QV

[w-u-2-o]

You showed your PC sound interface output is 48KHz. What about the Voicemeeter virtual devices in the sound control panel? Input and output?

Did you try switching to MME as I suggested?

[vk2qv]

Both VM virtual devices are configured to 48kHz. I also tried using MME, but that didn’t yield any results. I’m starting to think the onboard sound card on my PC might be the culprit. What puzzles me, though, is why the VAC values begin to rise whenever I mute or disable B1 in VM.

VM10.png (20.34 KiB) Viewed 5 times

VM11.png (19.27 KiB) Viewed 5 times

73 VK2QV