Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-db01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 29FE138000081; Thu, 8 Sep 2011 07:38:39 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1R1cvP-00074E-LW for rs_out_1@blacksheep.org; Thu, 08 Sep 2011 12:37:43 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1R1cvO-000745-RH for rsgb_lf_group@blacksheep.org; Thu, 08 Sep 2011 12:37:42 +0100 Received: from mail-yi0-f43.google.com ([209.85.218.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1R1cvM-0002eR-6u for rsgb_lf_group@blacksheep.org; Thu, 08 Sep 2011 12:37:42 +0100 Received: by yia27 with SMTP id 27so758767yia.16 for ; Thu, 08 Sep 2011 04:37:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=OWT2nsF/ZKfhcrVNOHWnx+pFJaWdEMdRWNja47Y3DBU=; b=qZYefcTmaDRfAsOk7GU3LAGEGa8JRVK38xMrwTDeINocKk1/Se+4T3XhdsvmnPcT5E MZ3m9qyTrRbXtzMcCEdlyQIXxAxuc2SCsw3yPP338Fgv2jxESYq38gSLYMNTQEaok9jH N5ZMwovil55N4i8YmAtqLBg9Lumc62EZablbs= MIME-Version: 1.0 Received: by 10.68.55.227 with SMTP id v3mr980900pbp.519.1315481853210; Thu, 08 Sep 2011 04:37:33 -0700 (PDT) Received: by 10.142.188.7 with HTTP; Thu, 8 Sep 2011 04:37:33 -0700 (PDT) In-Reply-To: <4E68988D.40108@iup.uni-heidelberg.de> References: <4E68988D.40108@iup.uni-heidelberg.de> Date: Thu, 8 Sep 2011 12:37:33 +0100 Message-ID: From: Roger Lapthorn To: rsgb_lf_group@blacksheep.org X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: My LF /p RX... Content-Type: multipart/alternative; boundary=bcaec53ae9bc91b1f704ac6c7cec X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=HTML_MESSAGE autolearn=no version=2.63 X-SA-Exim-Scanned: Yes Sender: owner-rsgb_lf_group@blacksheep.org Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:446135296:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d005.2 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d40554e68a93e708e X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none --bcaec53ae9bc91b1f704ac6c7cec Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable That is neat Stefan. Presumably one could use a 10MHz GPS locked source and divide this down as the LO and produce an output directly for SL. Then the converter could be used for extremely narrowband modes too? Maybe you need both a GPS derived 10kHz signal to calibrate SL and GPS derived 10MHz for the converter. 73s Roger G3XBM 2011/9/8 Stefan Sch=E4fer > LF, > > Some OMs asked me to show them my /p LF receiver circuit. So i took some > time and draw another ugly schematic ;-) A colleague took a photo which i= s > far better as of my mobile phone camera... > > It was a grown project and some things could be done different but the RX > works well and seems to be sensitive. The CW QSOs with M0BMU, G3KEV, DF6N= M, > PA0A and HB9ASB were done with this RX. > > The RX has a 50 Ohm input and uses a SBL-3 DBM. The circuit just uses a > single BF862 amplification stage (about 20 dB gain), the rest is passive.= LO > frequency is 125 kHz which is achieved from down dividing 4 MHz (xtal) by= a > CMOS4060. So the IF is at 12 kHz for a 137 kHz signal. 12 kHz can be samp= led > by the soundcard and so it can be processed by SpecLab. In SpecLab, furth= er > band limiting, noise blanking, a auto notch filter, a frequency shift to = a > 700 Hz CW sidetone and a narrow CW filter can be realised. > It is a wideband receiver that displays 125...149 kHz if a sample rate of > 48 kS/s is used. Some internal filter are focusing on the LF amateur band > and provide a limiting of strog outside BCD stations such as DLF, DCF39 a= nd > so... > > The circuit consumes just about 12 mA at 12 VDC! Thus it is possible to r= un > it in combination with a 1W 5VDC->12VDC converter supplies by the USB por= t > of a netbook. I found that this causes NO further QRM in the frequency ra= nge > of interest! It rather can be an advantage since the system can run > completely floating. So no additional battery is needed in /p operation. = The > box size is 83mm x 66mm x 28mm, so about like a cigarette box. > > A photo is here: http://dl.dropbox.com/u/**19882028/LF/DK7FC-p%20LF%20RX.= * > *jpg > > And the homedrawn schematic is here: http://dl.dropbox.com/u/** > 19882028/LF/DK7FC%20LF-p%20RX%**20converter.jpg > > > Thanks to Markus/DF6NM and Ha-Jo/DJ1ZB for suggestions, advice and the > discussion! Thanks to Marco/IK1ODO for the SBL-3!! > > 73, Stefan/DK7FC > > --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm https://sites.google.com/site/sub9khz/ --bcaec53ae9bc91b1f704ac6c7cec Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable That is neat Stefan.

Presumably one could use a 10MHz GPS locked sou= rce and divide this down as the LO and produce an output directly for SL. T= hen the converter could be used for extremely narrowband modes too?

Maybe you need both a GPS derived 10kHz signal to calibrate SL and GPS = derived 10MHz for the converter.

73s
Roger G3XBM

2011/9/8 Stefan Sch=E4fer <Stefan.Schaefer@iup.uni-h= eidelberg.de>
LF,

Some OMs asked me to show them my /p LF receiver circuit. So i took some ti= me and draw another ugly schematic ;-) A colleague took a photo which is fa= r better as of my mobile phone camera...

It was a grown project and some things could be done different but the RX w= orks well and seems to be sensitive. The CW QSOs with M0BMU, G3KEV, DF6NM, = PA0A and HB9ASB were done with this RX.

The RX has a 50 Ohm input and uses a SBL-3 DBM. The circuit just uses a sin= gle BF862 amplification stage (about 20 dB gain), the rest is passive. LO f= requency is 125 kHz which is achieved from down dividing 4 MHz (xtal) by a = CMOS4060. So the IF is at 12 kHz for a 137 kHz signal. 12 kHz can be sample= d by the soundcard and so it can be processed by SpecLab. In SpecLab, furth= er band limiting, noise blanking, a auto notch filter, a frequency shift to= a 700 Hz CW sidetone and a narrow CW filter can be realised.
It is a wideband receiver that displays 125...149 kHz if a sample rate of 4= 8 kS/s is used. Some internal filter are focusing on the LF amateur band an= d provide a limiting of strog outside BCD stations such as DLF, DCF39 and s= o...

The circuit consumes just about 12 mA at 12 VDC! Thus it is possible to run= it in combination with a 1W 5VDC->12VDC converter supplies by the USB p= ort of a netbook. I found that this causes NO further QRM in the frequency = range of interest! It rather can be an advantage since the system can run c= ompletely floating. So no additional battery is needed in /p operation. The= box size is 83mm x 66mm x 28mm, so about like a cigarette box.

A photo is here: http://dl.dropbox.com/u/19882028/LF/DK= 7FC-p%20LF%20RX.jpg

And the homedrawn schematic is here: http://dl.dro= pbox.com/u/19882028/LF/DK7FC%20LF-p%20RX%20converter.jpg<= br>

Thanks to Markus/DF6NM and Ha-Jo/DJ1ZB for suggestions, advice and the disc= ussion! Thanks to Marco/IK1ODO for the SBL-3!!

73, Stefan/DK7FC




--
http://g3xbm-qrp.blogspot.com/http://www.g3xbm.co.u= k
http://www.= youtube.com/user/g3xbm
https://sites.google.com/site/sub9khz/

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