Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dl01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 9B87F380000B1; Thu, 8 Sep 2011 08:28:45 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1R1di5-0002nt-Tn for rs_out_1@blacksheep.org; Thu, 08 Sep 2011 13:28:01 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1R1di5-0002nk-9e for rsgb_lf_group@blacksheep.org; Thu, 08 Sep 2011 13:28:01 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1R1di3-0005H5-JY for rsgb_lf_group@blacksheep.org; Thu, 08 Sep 2011 13:28:01 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id p88CRwrh023462 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 8 Sep 2011 14:27:58 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id p88BwF0U027887 for ; Thu, 8 Sep 2011 13:58:15 +0200 Message-ID: <4E68ADC8.2080103@iup.uni-heidelberg.de> Date: Thu, 08 Sep 2011 13:58:00 +0200 From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <4E68988D.40108@iup.uni-heidelberg.de> In-Reply-To: X-Spam-Score: 1.4 (+) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RATWARE_GECKO_BUILD=1.426 Subject: Re: LF: My LF /p RX... Content-Type: multipart/alternative; boundary="------------070406030102030204060002" 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: 0:2:455552864:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d4acf4e68b4fd5de1 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. --------------070406030102030204060002 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by relay.uni-heidelberg.de id p88CRwrh023462 Hi Roger, Am 08.09.2011 13:37, schrieb Roger Lapthorn: > That is neat Stefan. > > Presumably one could use a 10MHz GPS locked source and divide this=20 > down as the LO and produce an output directly for SL. Then the=20 > converter could be used for extremely narrowband modes too? Yes this is of course possible too. What i have not drawn in that=20 circuit is a PLL stage that lockes the LO frequency. I use a 10 kHz ref=20 frequency for that but just used that a few times and think about=20 throwing it out again. Last weekend in France i received OE5ODL's "5" in QRSS-60 too. Just a=20 very slow drift, no problem. But my RX was inside the car and so=20 temperatures change when opening and closing the door. At home this is=20 even less critical i assume. > > Maybe you need both a GPS derived 10kHz signal to calibrate SL and GPS=20 > derived 10MHz for the converter. Well if you use 10 MHz ref frequency and down divide that by a 4060 (you=20 will need HC or HCT types then) you will get even lower frequencies than=20 needed. If one of these (e.g. 10000 kHz / 64 =3D 156.25 kHz for the LO an= d=20 then 10000 kHz / 512 =3D 19.53125 kHz for the soundcard drift correction)= =20 frequencies are further down divided, you can use the 10 MHz ref for=20 soundcard locking as well. You can then simply inject that frequency to=20 the converted signal (say using a 100 pF cap or so) or run the PC in=20 stereo mode and use the 2nd channel... 73, Stefan > > 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 is 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, 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 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 sampled by the soundcard and > so it can be processed by SpecLab. In SpecLab, further 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 and so... > > 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 port 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 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.j= pg > > > 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/ > --------------070406030102030204060002 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Hi Roger,

Am 08.09.2011 13:37, schrieb Roger Lapthorn:
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?
Yes this is of course possible too. What i have not drawn in that circuit is a PLL stage that lockes the LO frequency. I use a 10 kHz ref frequency for that but just used that a few times and think about throwing it out again.
Last weekend in France i received OE5ODL's "5" in QRSS-60 too. Just a very slow drift, no problem. But my RX was inside the car and so temperatures change when opening and closing the door. At home this is even less critical i assume.

Maybe you need both a GPS derived 10kHz signal to calibrate SL and GPS derived 10MHz for the converter.
Well if you use 10 MHz ref frequency and down divide that by a 4060 (you will need HC or HCT types then) you will get even lower frequencies than needed. If one of these (e.g. 10000 kHz / 64 = 156.25 kHz for the LO and then 10000 kHz / 512 = 19.53125 kHz for the soundcard drift correction) frequencies are further down divided, you can use the 10 MHz ref for soundcard locking as well. You can then simply inject that frequency to the converted signal (say using a 100 pF cap or so) or run the PC in stereo mode and use the 2nd channel...

73, Stefan



73s
Roger G3XBM

2011/9/8 Stefan Schäfer <Stefan.Schaefer@iup.uni-heidelberg.de>
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 is 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, 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 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 sampled by the soundcard and so it can be processed by SpecLab. In SpecLab, further 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 and so...

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 port 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 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




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

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