Message-ID: <55D0D89A.3080400@posteo.de>
Date: Sun, 16 Aug 2015 20:38:18 +0200
From: DK7FC <selberdenken@posteo.de>
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To: rsgb_lf_group@blacksheep.org
References: <69624027609740299A8700F6BD23175F@AGB> <55CF747D.6040909@posteo.de> <C0B005B43382419EA510890EC2452941@AGB> <55CFA62B.5010301@posteo.de> <524DB27F17C843798472D2E9E7BA820B@AGB>
In-Reply-To: <524DB27F17C843798472D2E9E7BA820B@AGB>
Subject: Re: LF: Some LF again
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Status: O

Hello G,

As far as i know, the dynamic range of these dongles is not suitable. 60 
dB may be nice for playing arround but if you want to have a real RX for 
weak signal detection, something serious which is running 24/7, like 
Gary's grabber, you better spend the time and a bit of money and build 
something with 100 dB dynamic range. Or, if you don't like building your 
own stuff, buy some ready to use equipment, which is however just half 
of the hobby, in my opinion ;-)
But designs covering a whole band (VLF/LF/MF) are up to date i find. Not 
the SSB and dial stuff.

73, Stefan

Am 16.08.2015 18:48, schrieb Graham:
> Thanks  Stefan,
>
> Gary  sent a copy  of his   cct ,   Im wondering  what  one  of the  
> usb dongles  would  make of it ,  pre-amp  and  band pass filters  ...
>
> 73-G,
>
> --------------------------------------------------
> From: "DK7FC" <selberdenken@posteo.de>
> Sent: Saturday, August 15, 2015 9:50 PM
> To: <rsgb_lf_group@blacksheep.org>
> Subject: Re: LF: Some LF again
>
>> Hi G,
>>
>> No, i've made to many modifications from time to time. There is no up 
>> to date schematic.
>> But, it is a typical design. A suitable band pass filter, impedance 
>> converter matching to a SBL-3 mixer. The LO is 125 kHz, down-divided 
>> by a CMOS 4060 and a 4 MHz xtal. Then an IF-LPF. That's all. You may 
>> need an additional amp stage, depending on the incoming signal level...
>>
>> 73, Stefan
>>
>> Am 15.08.2015 21:16, schrieb Graham:
>>> Hi Stefan
>>> Do you  have  a  link  to  the  CCT  for  the  soundcard  Rx ?
>>>
>>> Tnx-G
>>>
>>> http://myweb.tiscali.co.uk/wgtaylor/136SCRX.jpg
>>>
>>> --------------------------------------------------
>>> From: "DK7FC" <selberdenken@posteo.de>
>>> Sent: Saturday, August 15, 2015 6:18 PM
>>> To: <rsgb_lf_group@blacksheep.org>
>>> Subject: LF: Some LF again
>>>
>>>> Hi LF,
>>>>
>>>> I'm back there is WSPR-15 for some time. The power is reduced by 4 
>>>> dB, unfortunately.
>>>>
>>>> Maybe someone can catch a trace anyway :-)
>>>>
>>>> 73, Stefan/DK7FC
>>>>
>>>
>>
>