That is very interesting. When I had this problem, the VAC Control panel was clearly showing 44100 Hz for one (or more) of the VAC cables. I guess the problem can manifest itself in different ways which makes it a more frustrating Windows issue to identify.
-Tim ----- W4TME -----Original Message----- From: Scott Myers [mailto:ac...@ameritech.net] Sent: Tuesday, July 13, 2010 8:59 AM To: Tim Ellison; FlexRadio@flex-radio.biz Subject: RE: [Flexradio] Harmonics with Ham Radio Deluex (HRD) & DM780 Tim, You said; "... open the VAC Control panel... It will show the operating sampling rates of the cables. If the VAC cable's sampling rate does not match the same rate as defined in the PowerSDR VAC configuration, then Windows (7 / Vista) has not allowed the application to change the device's (VAC) sampling rate." It's not that simple I am afraid and you CAN'T SEE this inconsistency within VAC when it is running or otherwise. VAC WILL show a 48K sampling rate matching DM780 & PowerSDR's settings even when Windows is choking it down! At least it does on both my 64 and 32 bit Win 7 systems. (I haven't checked my XP laptop, but you indicate it doesn't have this setting adjustment.) I had PowerSDR set to 48K and DM780 set to 48K. With both running, VAC control panel showed them connected together at 48K. So they appeared to all match quite nicely and be running well. (Running VAC 4.09) But in reality, there was a "step-down" and "step-up" midstream through VAC and the windows drivers due to these Windows audio settings I was unaware of. This clear was causing poor data rate conversions, which caused the harmonic spikes. You simply can't see that you are being bottlenecked by Windows "under the hood" when looking into VAC control panel. That is why I was stymied for so long. But once changed, it was beautiful. So for some reason, VAC doesn't report this little inconsistency. VAC's manual does seem to point this out in the more advance setting area of the manual, which is how I found it. 73, Scott AC8DE -----Original Message----- From: Tim Ellison [mailto:telli...@itsco.com] Sent: Tuesday, July 13, 2010 8:37 AM To: Scott Myers; FlexRadio@flex-radio.biz Subject: RE: [Flexradio] Harmonics with Ham Radio Deluex (HRD) & DM780 This is real easy to check to see if you actually have this situation. When PowerSDR and the digital mode program are running, open the VAC Control panel and look at the two defined VAC "cables". It will show the operating sampling rates of the cables. If the VAC cable's sampling rate does not match the same rate as defined in the PowerSDR VAC configuration, then Windows (7 / Vista) has not allowed the application to change the device's (VAC) sampling rate. This is not applicable to XP systems, as there is no controls for changing an audio device's default sampling rate. Also, this doesn't seem to be a systemic problem. Try setting the PowerSDR VAC sampling rate to something lower than 44100 (the default sampling rate Windows sets for the VAC cabs) and it seems to set the sampling rates just fine. One more point while we are on the subject of VAC and sampling rates. In the upcoming PowerSDR 2.x software, there have been several improvements to the VAC ring buffers. The net effect is that previously it was recommended that you run the VAC sampling rate at 48 KHz when using PowerSDR v1.x. Now with PowerSDR v2.x this recommendation is moot. It is best to set the VAC sampling rate to match the digimode program's sampling rate so that an additional sampling rate conversion does not take place (which is what was responsible for the harmonics mentioned below). I am currently running Fldigi @ 12000 Hz (an even multiple of 48, 96 and 192) and the sampling rate configured for VAC in PowerSDR is set for 12000 Hz. It is working very well. -Tim ----- W4TME -----Original Message----- From: flexradio-boun...@flex-radio.biz [mailto:flexradio-boun...@flex-radio.biz] On Behalf Of Scott Myers Sent: Tuesday, July 13, 2010 7:57 AM To: FlexRadio@flex-radio.biz Subject: [Flexradio] Harmonics with Ham Radio Deluex (HRD) & DM780 I have heard others mention the harmonics as they have seen in PowerSDR as well when using DM780. I have been plagued by this from the beginning when I used HRD over a year ago. My "solution" was to tighten up the TX filters in PowerSDR so that harmonics wouldn't be transmitted. A Band-aid approach, but it worked to keep me clean on the air. HRD tech support pointed at Flex Radio and Vice-Verse. Well, as it turns out, it is neither of those party's fault. Nor is it VAC's fault. I have now discovered why it occurs, at least in my particular case. I knew it had something to do with the data not being converted correctly, but I didn't know why it occurred. I had looked at all the settings in PowerSDR and DM780. I had tried every possible driver and sample rate. Nothing seemed to work. So I contacted Eugene Muzychenko (writer of VAC) and asked him. He explained how VAC worked at a basic level and had me look at some things, using the manual to VAC. The problem kept pointing me back to the chain BETWEEN PowerSDR & DM780. Through Eugene's manual, I discovered there is an advanced settings in the audio of windows that can affect sample rates, regardless of what you do elsewhere. I found that there are some settings in windows that are defaulted to 44100 (CD Redbook settings) under advance audio settings for the line 1 & line 2 (VAC lines in my case) in control panel. It had both record and playback limited to 44100 in VAC! I finally had found the "magic switch". Once I set both the playback and record to 48000 in these tabs (Windows DVD sample rate settings), I went back to DM780 and looked at PowerSDR in TX mode. It is now clean, clean, clean! (Funny thing is that now I do see a single spike in the TX of FLDigi that wasn't there before, but that is another subject.) So for those that might have been experiencing this same thing, I thought I would share this little "fix". I hope it helps someone. 73, Scott AC8DE _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/ _______________________________________________ FlexRadio Systems Mailing List FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
