Message-ID: <4E4AD94F.4010107@kabelmail.de>
Date: Tue, 16 Aug 2011 22:55:43 +0200
From: DK1IS <DK1IS@kabelmail.de>
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To: rsgb_lf_group@blacksheep.org
References: <4E4AC760.3000202@kabelmail.de> <4E4ACFBF.1080507@freenet.de>
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Subject: Re: LF: Remote Receiving Antenna: UHF-Link
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Am 16.08.2011 22:14, schrieb wolf_dl4yhf:
> Hello Tom,
>
> Yes I use a UHF link, but "only" for VLF, single channel, covering 500 
> ... 20000 Hz. The dynamic range is somewhat limited as you can see on 
> the VLF stream's detail page: 
> http://abelian.org/vlf/detail.php?stream=vlf6&page=0
> But if strongs sferics are occasionally clipped (in the transmitter) 
> doesn't hurt that much for this application.
>
> One important thing was getting rid of the stereo encoder / decoder, 
> which I had used in the first setup (it was a cheap "HiFi" wireless 
> headphone in the 864 MHz band, which didn't deserve its name. Analog 
> stereo wideband FM, but noisy as hell).  Getting rid of the 
> stereo-stuff (tap the rx after the FM discriminator) gave a better 
> performance, and no aliasing effect caused by the strong Navy 
> transmitters in the vincinity of the 19 kHz pilot (there is no 'sharp 
> lowpass' before the stereo modulator which would have cured some of 
> the problems).
>
> The currently used stream is still analog, using a modified FM 
> wideband TX (which was once a cheap AM transmitter), and a wideband 
> RX. Today I'd go for a digital system, something with a 16-bit ADC on 
> the TX, and 16-bit DAC on the RX side. Not sure if the "bluetooth HiFi 
> wireless headphones" sold today would be up to the job. For example, 
> the Sennheiser RS 170 (digital, without compression, but datasheet not 
> very detailed).
>
> 73,
>    Wolf .
>
Hello Wolf,

thanks for zour info and the hints! I'll keep them in mind when fetching 
my pliers and fireing the soldering iron ...

73,
Tom, DK1IS

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    Am 16.08.2011 22:14, schrieb wolf_dl4yhf:
    <blockquote cite=3D"mid:4E4ACFBF.1080507@freenet.de" type=3D"cite">
      <meta content=3D"text/html; charset=3DISO-8859-15"
        http-equiv=3D"Content-Type">
      Hello Tom,<br>
      <br>
      Yes I use a UHF link, but "only" for VLF, single channel, covering
      500 ... 20000 Hz. The dynamic range is somewhat limited as you can
      see on the VLF stream's detail page: <a moz-do-not-send=3D"true"
        class=3D"moz-txt-link-freetext"
        href=3D"http://abelian.org/vlf/detail.php?stream=3Dvlf6&amp;page=3D=
0">http://abelian.org/vlf/detail.php?stream=3Dvlf6&amp;page=3D0</a>
      <br>
      But if strongs sferics are occasionally clipped (in the
      transmitter) doesn't hurt that much for this application.<br>
      <br>
      One important thing was getting rid of the stereo encoder /
      decoder, which I had used in the first setup (it was a cheap
      "HiFi" wireless headphone in the 864 MHz band, which didn't
      deserve its name. Analog stereo wideband FM, but noisy as hell).=A0
      Getting rid of the stereo-stuff (tap the rx after the FM
      discriminator) gave a better performance, and no aliasing effect
      caused by the strong Navy transmitters in the vincinity of the 19
      kHz pilot (there is no 'sharp lowpass' before the stereo modulator
      which would have cured some of the problems).<br>
      <br>
      The currently used stream is still analog, using a modified FM
      wideband TX (which was once a cheap AM transmitter), and a
      wideband RX. Today I'd go for a digital system, something with a
      16-bit ADC on the TX, and 16-bit DAC on the RX side. Not sure if
      the "bluetooth HiFi wireless headphones" sold today would be up to
      the job. For example, the Sennheiser RS 170 (digital, without
      compression, but datasheet not very detailed).<br>
      <br>
      73,<br>
      =A0=A0 Wolf .<br>
      <br>
    </blockquote>
    Hello Wolf,<br>
    <br>
    thanks for zour info and the hints! I'll keep them in mind when
    fetching my pliers and fireing the soldering iron ...<br>
    <br>
    73,<br>
    Tom, DK1IS<br>
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