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Date: Fri, 15 Aug 2014 20:25:29 -0400
Message-ID: <CACMmJPfvjRN5e5r413c4-G5mp9DsVF00oZaMt-t51HuNgb2g5A@mail.gmail.com>
From: Warren ZIegler <wh2xil@gmail.com>
To: rsgb_lf_group@blacksheep.org
Subject: Re: LF: USB Sound Card?
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Status: O

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 <g8fzk@g8fzk.fsnet.co.uk> 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" <DG3LV@gmx.net>
> Sent: Friday, August 15, 2014 11:27 PM
> To: <rsgb_lf_group@blacksheep.org>
> 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 hvanesce@comcast.net:
>>>
>>> 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:*owner-rsgb_lf_group@blacksheep.org
>>> [mailto:owner-rsgb_lf_group@blacksheep.org] *On Behalf Of *Gary - G4WGT
>>> *Sent:* Friday, August 15, 2014 3:25 PM
>>> *To:* rsgb_lf_group@blacksheep.org
>>> *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 <wd2xgj@gmail.com
>>>     <mailto:wd2xgj@gmail.com>> 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
>>>
>>
>