Thetis & CW Skimmer

[w9ac]

I am trying to activate SDC CW Skimmer with Thetis by following Richie's YouTube tutorial linked here:

https://www.youtube.com/watch?v=iQd_E4ffO-w

VAC is used for IQ data transfer between Thetis and CW Skimmer. Past group posts have indicated that VAC and IQ don't mix together well, but apparently Richie has made it work.

When activating IQ in the Audio Setup window, spurs are observed on the panoramic display and no CW decoding occurs in Skimmer (see images below). I have also included my Audio setup screen captures.

Anything obvious that would contaminate the IQ stream?

Paul, W9AC

[w9mdb]

Turn off SwapIQ maybe?

[w9ac]

Turn off SwapIQ maybe?

Required to have IQ Swap for Skimmer and makes no difference whether checked or not. Also, I failed to mention that non-VAC audio is severely distorted any time IQ is activated. All Thetis Audio Setup parameters are the same as Richie's.

Paul

[w-u-2-o]

You didn't post a screen shot of the Skimmer side setup. The VAC cables are setting themselves to 192KHz, not 48KHz, and the under and overflow counters are running wild. Check your sample rate in Skimmer and ensure it matches with Thetis.

You might also leave all the buffer controls in Thetis set to automatic unless there is some compelling reason not to.

[w9mdb]

I had to run the VAC "Fixed" because without it the FT8 signals would show drifting.
non-Fixed is probably OK with CW.
I'm not on-air now -- waiting for the new ANAN-G2 1K to show up on my doorstep soon....

[w9ac]

The VAC range was set early on to accept 8 kHz to 196K sample rates. That was from Nigel, a long time ago. However, I just forced all VAC cables to a 48 kHz SR and the overflows stopped. That corrects the spur problem but there's still no decode.

CW Skimmer is integrated with SDC software. Setup images attached.

I'll ask Richie for a print-screen of his VAC setup.

Paul, W9AC

[w-u-2-o]

Progress!

How does the spectral display (horizontal waterfall) look in Skimmer? Does it appear OK, clean, without any weird artifacts, spurs, etc?

Did you put the buffer settings on auto? Try increasing the VAC main buffer size?

[SM3PZG]

Here are my settings. Using VoiceMeeter VAC. Works great.

Thetis SDC.png (679.48 KiB) Viewed 14833 times

[w9ac]

First, thanks to all who replied with suggestions...

I finally solved the IQ output problem by reducing the Rx1 sample rate from 1.536 Mbps to 384 kbps. Until then, no real progress was being made.

Thetis version: 2.10.3.5
P2 FW: 2.2.2

Paul, W9AC

[I2NOY]

I had same issue and reducing sample rate solved it.
Probably protocol 2 is not so stable on my 7000 DLE Mk II.
73.

[Michael]

a quick question.

Has the issue with ghost spurs/spots within SDC Skimmer be solved. If yes, how can I achieve this?

Decoding of SDC Skimmer works fine with streamed I/Q data from Thetis. Spot data is being sent to N1MM bandmap using the SDC Telnet server. However, some of the decoded spots are duplicated (mirrowed). They appear twice at different freq in the Skimmer Waterfall and also in the N1MM bandmap but obviously are only present once. Is there are way to avoid this?

Best regards,

Michael, DF2RQ