Thanks to Stefan, Jim, Tobias, and Gary for your help and suggestions.
I deleted the Windows driver for the internal sound card and re-booted
the machine, it then reinstalled a fresh driver and the internal card
is working.
I will still be getting another sound card since the digital voice
program FreeDV requires two sound cards.
73 Warren
On Fri, Aug 15, 2014 at 7:48 PM, Graham <[email protected]> wrote:
> Thanks for the run down Tobias
>
> The windows re-sampling caused problems with wspr in the early days
> on MF , as its possible that wspr had never been used in a situation
> where 100% of the signal arrived at the RX . qsb was normally part
> of the process ..
>
> This caused a strange problem . where strong signals failed decode
> , where as low level with qsb did
>
> It eventually transpired , that the sampling rates where not quite
> the same on all systems and the short bursts masked the timing
> differences , tested by sample audio files and a stop-watch
>
> Later , we found Opera / Ros [ ros was first] that decodes failed
> with other software running , additional routines where added to
> ensure the sample rate was held at the correct speed , since then ,
> all has been ok
>
> I used soundblaster 5.1 external usb card , can be picked up s/h now
> on ebay for very little
>
> 73-G,
> G0NBD
>
> --------------------------------------------------
> From: "Tobias DG3LV" <[email protected]>
> Sent: Friday, August 15, 2014 11:27 PM
> To: <[email protected]>
> Subject: Re: LF: USB Sound Card?
>
>
>> Hi Jim, Gary !
>>
>> Experiences with Software Defined Radios ("Softrock" type) over years
>> showed me the highs and lows of using a soundcard as an A/D-converter for
>> HamRadio use. The situation improved from using the onboard-devices to
>> professional external Firewire- or USB-2.0 soundcards as they became
>> available at reasonable prices.
>>
>> to A) it's true, the windows type drivers support up to 16 Bit only. There
>> are some issues to sampling rate stability under windows, too. That's why
>> SDR-programs like Winrad, HDSDR etc. use the alternative "ASIO" driver
>> model, where 24 Bits are supported natively and where the latency is
>> smallest. ASIO drivers typically are bundled with (professional) soundcards
>> for studio-recording. I had the usual "EMU-0202-USB" card, which was
>> sampling at 192kHz/24 Bit. As this is available no longer, today I use an
>> "Icon Cube" and "Icon Cube pro" (2/4 Channel,192kHz,24Bit,USB-2.0) for my
>> softrock SDR. They are not too expensive and do a good job!
>>
>> to B) Windows has different properties for the hardware sampling rate and
>> the offered (simulated) sampling rate. If these are not identical, there is
>> a software up/down-resampling done by windows. You have to set the correct
>> sampling rate at the hardware-settings (!) of the chosen soundcard
>> input/output. (sometimes Win7 resets this to 44.1 kHz/16Bit at another
>> booting, so you have to check this first after booting up the PC.)
>> e.g. Even if the soundcard is just sampling at 48kHz, the windows drivers
>> offer 96 and 192 kHz as well, but actual audio-data is still not more than
>> 48kHz, the rest of the spectrum is filled with "blanks".
>>
>> to C) Typically the anti-aliasing filters of a soundcard are bound to the
>> current (hardware-) sampling rate (=Nyquist) and not be static. Those
>> filters are digital ones and part of the A/D converter chips. But the
>> datasheets of soundcards shows the filters of the 44.1/48 kHz sampling rate
>> only (0-20 kHz), as this is the standard where the "dB-"measurements are
>> done.
>>
>> 73 kHz Rx :
>> In Europe you can receive the DCF77 signals (77.5 kHz) very well by a
>> length of wire (or better a PA0RDT) and directly attaching it to an input of
>> a 192 kHz soundcard. (Here 55dB above noise at 600km distance, software
>> time-decoding by "SoDiRa" SDR-software). It is the same setup as used for
>> SAQ-listening at 17.2 kHz (using HDSDR).
>>
>> For decoding digimodes (WSPR,JT65,WSQ...) a simple USB-micro-soundcard
>> ($5) or onboard is ok, the programs just use "mono" and 48kHz at most, even
>> the cheapest (for headset use) do well.
>>
>> 73 de dg3lv Tobias
>>
>> Am 15.08.2014 22:12, schrieb [email protected]:
>>>
>>> Gary,
>>>
>>> I use a number of expensive and inexpensive external (USB) audio
>>> interfaces, and I like them all (good sensitivity, good dynamic range);
>>> but I experience the following limitations:
>>>
>>> A)
>>>
>>> I have not been able to persuade Windows and/or Speclab to process 24
>>> bits (I have been successful in applying 24-bit settings in
>>> Windows>ControlPanel>Sound and Speclab, but have not acquired valid
>>> data after doing so; and accordingly have always used 16-bit settings
>>> with 24-bit external audio interfaces, even though I need at least 24
>>> bits for dynamic range considering VLF and LF environmental noise in
>>> some of my locations)
>>>
>>> B)
>>>
>>> Similarly to the above, I have been able to set up Windows and Speclab
>>> for 192kHz sample rates, but have not been able to view past 48kHz
>>> without aliasing (and accordingly I settle for 96kHz settings and
>>> interfaces in most cases)
>>>
>>> C)
>>>
>>> All of my external audio interfaces have steep low-pass filters at or
>>> near 22kHz pole frequency, so SNR is compromised for signals at 20kHz
>>> and above. I’ve disassembled some of these interfaces in attempts to
>>> modify the low-pass filter cutoff frequencies, but without a schematic
>>> could not be certain regarding changes.
>>>
>>> Have you seen any of the above issues with internal or external audio
>>> interfaces that you have used?
>>>
>>> 73, Jim AA5BW
>>>
>>> *From:*[email protected]
>>> [mailto:[email protected]] *On Behalf Of *Gary - G4WGT
>>> *Sent:* Friday, August 15, 2014 3:25 PM
>>> *To:* [email protected]
>>> *Subject:* Re: LF: USB Sound Card?
>>>
>>> Hi Warren,
>>>
>>> Yes, I had an internal (on main board) & used it for a while for my
>>> grabber when 73kHz was first allocated to USA.
>>> It was good to about 94kHz.
>>>
>>> The SB0490 I suggested is only 96kHz :-((
>>>
>>> *73, de Gary - G4WGT*
>>>
>>> * *
>>>
>>> *MF-LF-VLF Grabber :http://myweb.tiscali.co.uk/wgtaylor/grabber2.html*
>>>
>>> *Web :http://myweb.tiscali.co.uk/wgtaylor/index.html*
>>>
>>>
>>>
>>> .
>>>
>>> On 15/08/2014 20:09, Warren Ziegler wrote:
>>>
>>> I guess I should have been more specific .
>>>
>>> What I am seeking is are some sound cards more stable with respect
>>> to sampling rate and calibration? Also, any advantage to 24bit A/D
>>> for LF data modes?
>>>
>>> I wonder if anyone has tried 192kHz sample rate for direct
>>> reception of 73kHz?
>>>
>>> 73 & Tnx Warren
>>>
>>> On Fri, Aug 15, 2014 at 2:27 PM, Warren Ziegler <[email protected]
>>> <mailto:[email protected]>> wrote:
>>>
>>>
>>> I just acquired a Windows Vista tower computer - the price was right
>>> it was free!
>>>
>>> Seems that there is a problem with the internal sound card, but
>>> everything else checks out FB.
>>>
>>> I plan on using it with WSPR and other digital modes, am thinking of
>>> an external USB sound card - will any old sound card do ? Or do I
>>> need one with a calibrated sampling rate? I suspect that I will need
>>> something really good for Spectrum Laboratory if I want to sample at
>>> microHertz rates.
>>>
>>> 73 & Tnx Warren K2ORS
>>>
>>>
>>>
>>> --
>>> 73 Warren K2ORS
>>> WD2XGJ
>>> WD2XSH/23
>>> WE2XEB/2
>>> WE2XGR/1
>>>
>>
>
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