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Re: LF: VLF exciter / signal generation in Spectrum Lab

To: <[email protected]>
Subject: Re: LF: VLF exciter / signal generation in Spectrum Lab
From: "Marco Cadeddu" <[email protected]>
Date: Tue, 31 Dec 2013 15:12:34 -0000
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Hello Wolf,
 
reading this message pushed me to check my netbook (a dot s from PackardBell) and surpise! in the properties I found that I could change the SR up to 192kHz!!!
So I tried and it works but.....
- although I can axtend the reception till 90 kHz, above 40 kHz the sensitivity falls (MDS is around -45÷50 dBm)
- when using SR above 48 kHz the calibration of SR doesn't work (even when the reference signal is in the good reception band) or using a 10 kHz external reference.
 
Anyway is ever a good idea to explore the capabilities, and this is a good occasion to wish to the group an Happy New Year!
 
73 de Marco, IK1HSS
----- Original Message -----
Sent: Sunday, December 29, 2013 6:50 PM
Subject: Re: LF: VLF exciter / signal generation in Spectrum Lab

Hi Graham,

About 74 kHz reception: I recently discovered that a Lenovo 'X61s' netbook, bought cheaply at a rally, supports true 192 kHz sampling with the onboard 'soundcard' (once one discovers where to configure that in the swamped windows 7 system control, or wherever they decided to put the soundcard control dialog today. IIRC it was "Properties of Microphone", translated from german into english).
Indeed the usable 'audio' range covers a few Hz to 96 kHz ! This would allow direct reception on 74 kHz, and also using DCF77, MSF, or similar time signal transmitters as reference for the sample rate correction...  SL could translate down into the audible range, and downsample to 48 or 24 kS/second, before sending the converted signal to other applications.

Anyway it would be much easier if the "hard coded frequency range" would simply be removed from the original Opera software, and completely leave it to the human operator to enter the frequency range in a simple input field.

73,
  Wolf .


Am 29.12.2013 18:56, schrieb Graham:
Thanks Wolf,
 
With the 8K signals  out side  the  Op decoder  , some  users  wanted  to  monitor the  test  , but  needed  a  way of  changing the  qrg  slightly to  match ,
 
The  other  thing , that  occurred  to  me  , was  the  other 75 K stations  , may have a  TA chance  using  Op4H , +6 dB gain over op1H   in the  'window'  time ,  may be  1  run or  2  max  ? ... recovering  the  8K audio  may  be a  problem ,  my  ra6790gm   has a  locked bfo  range  of  +/-  19KHz or  so  , but  , for  normal  ssb-rx  , then  a  shift  up from  1500  would be  needed [ may even  catch Bob  on 4H  hihi]
 
73-G,
 

Sent: Sunday, December 29, 2013 1:25 PM
Subject: Re: LF: VLF exciter / signal generation in Spectrum Lab

Hello Graham,

Am 29.12.2013 14:04, schrieb Graham:
Wolf,
 
Q How to  configure  SL  as audio  frequency   changer ?  
 
say   1500 Hz to  8 KHz , or , 8100 to  8200   etc
 
how is the  set  up  ?

The easiest way is using the 'narrowband filter', which can also shift frequencies.
Start by selecting 'Quick Settings' in the menu, then 'Other amateur radio modes', 'Narrow CW filter with adjustable xyz'. You can see the filter's passband on the main frequency scale, along with the 'zero beat' indicator similar to a web sdr. Grab the passband widh the mouse and move it to the 'source' frequency range. Alternatively, enter the frequency shift in numeric form on the filter control panel. Details:

http://www.qsl.net/dl4yhf/speclab/filters.htm#filter_controls_on_main_freq_scale


 
 
will SL  appeared as a  sound  source  ?
It can, but unfortunately only as an ASIO device. Microsoft's ever-changing driver model is so utterly complex that I gave up writing my own 'multimedia driver'. Also I didn't feel like re-inventing the wheel for XP, Vista, Win7, Win8, and whatever-comes-next...  :o)  Thus the easiest (??) method would be to use Virtual Audio Cable.

The more complex (but VAC-less) way, if ASIO is supported by the audio-receiving application, is decribed in the 'Audio I/O' manual:

http://www.qsl.net/dl4yhf/AudioIO/AudioIO_Manual.pdf

The relevant chapter would be "Installation of in_AudioIO.dll as an ASIO device".



Now back to the soldering iron..

73,  Wolf .



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