Return-Path: Received: from mtain-db08.r1000.mx.aol.com (mtain-db08.r1000.mx.aol.com [172.29.64.92]) by air-me04.mail.aol.com (v127_r1.1) with ESMTP id MAILINME044-8baf4b81010c23f; Sun, 21 Feb 2010 04:46:52 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-db08.r1000.mx.aol.com (Internet Inbound) with ESMTP id E6D9D380000AF; Sun, 21 Feb 2010 04:46:50 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Nj8NB-0005tN-EH for rs_out_1@blacksheep.org; Sun, 21 Feb 2010 09:45:09 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Nj8NA-0005tE-Sg for rsgb_lf_group@blacksheep.org; Sun, 21 Feb 2010 09:45:08 +0000 Received: from mail-bw0-f215.google.com ([209.85.218.215]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Nj8N7-0001fF-FC for rsgb_lf_group@blacksheep.org; Sun, 21 Feb 2010 09:45:08 +0000 Received: by bwz7 with SMTP id 7so1018569bwz.4 for ; Sun, 21 Feb 2010 01:44:59 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=RHbldvfiLbtiy6GVjfXoOsrdT867zLYtIrG0B7xM1Yk=; b=t24o+9NtwNIfMysKcsSfUYDCFnK74LnimvpCOKAi0Zsn7z41+vOFgTTaTxfSSkh+Um bY3eAusqFKAISNykYrDVigXwmFzYf3byJ2KblZ/xQBKa4LFtBO4s4e7cr8iYhO8G5+YK +wE+AaCOrxkmd63CKsw9B9ZLOrpEUnak0zIzo= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=uUwZJ8zMycszBZsJsDoSuPIqqRjYu4oShljEdC99jk+rtkwEQPw8E+Op0hAFVak095 3uLpw21HyCcHvhGG15eFO34mgp9cTy/tMf34y8vYCyZVLh8LavH8B9VQKFGKJ3Ef86jA NiCqe/+ihY7Xj8HBbLj7beI8j29Yd7KCX5XZM= MIME-Version: 1.0 Received: by 10.204.131.208 with SMTP id y16mr2686085bks.137.1266745498238; Sun, 21 Feb 2010 01:44:58 -0800 (PST) In-Reply-To: <4B80EFC0.1000800@online.fr> References: <4B80E27F.30302@telus.net> <4B80EFC0.1000800@online.fr> Date: Sun, 21 Feb 2010 09:44:58 +0000 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: SDR RX ideas for grabber... Content-Type: multipart/alternative; boundary=001517448ad87181cb0480192bd6 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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-AUTHENTICATION: mail_rly_antispam_dkim-m232.2 ; domain : googlemail.com DKIM : pass x-aol-sid: 3039ac1d405c4b81010a4b5d X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --001517448ad87181cb0480192bd6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Jean - Pierre... Is the circuit diagram correct ? Your two final op-amps used as differential amplifiers both have their inputs taken from teh same ndes,= yet are labelled to deliver I and Q. The first pair of op-amp do correctly take I and Q channels from the FST3253 mixer, but then their outputs are summed (differenced !) together. As far as I can see, I and Q outputs are the same signal. Also, there is very littel audio gain in the circuit= , so the receiver as shown requires plenty of RF input to deliver enough aud= io for teh typical soundcard An ERA-5 is a rather exotic device to use in the preamp - it has considerable gain right up to 8Ghz and could be difficult to kep stable. Better to use a MAR-3 at LF. Andy www.g4jnt.com On 21 February 2010 08:33, "Jean-Pierre M=E9r=E9 (F1AFJ)" wrote: > Hi Scott , > > Please , loock at : http://jpmere.online.fr/Grabber/Setup/Setup.htm > > It is my grabber on 2200m ! > > 73 qro Jean-Pierre f1afj > > > Scott Tilley a =E9crit : > > Hi All >> >> I was wondering if there is a simple solution that is fairly well >> documented for converting a softrock type receiver over to 2200m use? >> >> Any other suggestions on how to get a SDR on 2200m with a minimum of >> effort would be greatly appreciated. >> >> Regards, >> Scott >> >> >> >> >> > --001517448ad87181cb0480192bd6 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
Jean - Pierre...
=A0
Is the circuit diagram correct ?=A0=A0 Your two final op-amps=A0used= as differential amplifiers=A0both have=A0their inputs taken from teh same= ndes,=A0yet are labelled to deliver I and Q.=A0=A0=A0The first pair of op= -amp do correctly take I and Q channels from the FST3253 mixer, but then= their outputs are summed (differenced !) =A0together.=A0=A0 As far as I= can see,=A0=A0 I and Q outputs are the same signal.=A0 Also, there is=A0v= ery littel audio gain in the circuit, so the receiver as shown requires pl= enty of RF input to deliver enough audio for teh typical soundcard=20
=A0
An ERA-5 is a rather exotic device to use in the preamp - it has=A0co= nsiderable gain right up to 8Ghz and could be difficult to kep stable.=A0= =A0 Better to use a MAR-3 at LF.
=A0
On 21 February 2010 08:33, "Jean-Pierre M= =E9r=E9 (F1AFJ)" <jpm.f1afj@online.fr> wrote:
Hi Scott ,

Please , loo= ck at : =A0 =A0 http://jpmere.online.fr/Grabber/Setup/Setup.htm
It is my grabber on 2200m !

73 qro Jean-Pierre f1afj

Scott Tilley a =E9crit :=20

Hi All

I was wondering= if there is a simple solution that is fairly well documented for converti= ng a softrock type receiver over to 2200m use?

Any other suggestions on how to get a SDR on 2200m with a minimum of= effort would be greatly appreciated.

Regards,
Scott


=



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