Return-Path: X-Spam-DCC: paranoid 1233; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.4 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_MESSAGE autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id t54ClK9p022111 for ; Thu, 4 Jun 2015 14:47:20 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Z0UVV-0006ks-A6 for rs_out_1@blacksheep.org; Thu, 04 Jun 2015 13:44:25 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Z0UVU-0006kj-W1 for rsgb_lf_group@blacksheep.org; Thu, 04 Jun 2015 13:44:24 +0100 Received: from mail-wg0-f53.google.com ([74.125.82.53]) by relay1.thorcom.net with esmtps (TLSv1.2:AES128-GCM-SHA256:128) (Exim 4.85) (envelope-from ) id 1Z0UVS-00084s-Vj for rsgb_lf_group@blacksheep.org; Thu, 04 Jun 2015 13:44:23 +0100 Received: by wgv5 with SMTP id 5so32687184wgv.1 for ; Thu, 04 Jun 2015 05:44:22 -0700 (PDT) X-DKIM-Result: Domain=gmail.com Result=Good and Known Domain DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=b9Bv2CtnUn7gTJsVY7spqRIlBThUyDZmgkq6wIhB6js=; b=aAqU+uX+kqZ8mQPeeBBfZix1nvxJxlIxd2eAodxCx42EHyHu+DBkTSYo3/crOfTLyt zzAVi7uXiGVs0aKDvIvi7nWxNuFmHN3UUTv4fvtPSuHH7aPpsHJeVdiScQ0VveU6Sejf GYeIUYu0XsiN7E008K1Jg5u50OaSHCm4FKvFkd4CcdYrHdJz8Sr6Nb3sHiykL1F4LYvS JJW935hwLy9pRuLz8gDZhrSr1gQvmIKhpo6YjNeYOL+Vc59L2nHkstXRf/W/FszfpTIo o8Dz2DBuailoATxfdwO13ofiH+qF9dRe6kYjsfv6XOl6UB8riadXFg81mu1xRnE8srnS jNjg== MIME-Version: 1.0 X-Received: by 10.194.23.66 with SMTP id k2mr38709441wjf.18.1433421861997; Thu, 04 Jun 2015 05:44:21 -0700 (PDT) Received: by 10.28.136.132 with HTTP; Thu, 4 Jun 2015 05:44:21 -0700 (PDT) In-Reply-To: <1052531792.20150604131722@chriswilson.tv> References: <1052531792.20150604131722@chriswilson.tv> Date: Thu, 4 Jun 2015 13:44:21 +0100 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org X-Scan-Signature: 79aab7440207271f32757adc503f8c76 Subject: Re: LF: IDC-136-BLT 136kHz receivers Content-Type: multipart/alternative; boundary=047d7b3a8b3ae5d35f0517b08898 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 3432 --047d7b3a8b3ae5d35f0517b08898 Content-Type: text/plain; charset=UTF-8 Haven't seen / played / even heard of them, but we can get a rough idea of its possible performance just by looking at the picture of the PCB on the web page. Image filterign is teh biggest problem with this single conversion route. Assuming all the image filtering is done by those three coils in cans that are visible on the photograph:. An AADE design for a suitable third order bandpass filter, with 8kHz bandwidth and allowing a compromise 1dB ripple suggests image rejection at 125kHz will only be around 30dB. (Top coupled capacitor design, so low side rejectino is better than high side) Not sure what signals are down there to get through, and a highly resonant antenna will help a lot more with image rejection - but if its for a grabber, you're probably going to use a broadband active antenna. Can't make out much else from the web page photos, and it give no specification. But such a simple converter concept can't go hopelessly wrong, if you accept the limited image filter that would be achieved with three tuned circuits If I were to try that approach, I'd got for an IF of 15 - 19kHz, at the top end of normal soundcard coverage, so bringing the image down to 105kHz and making it easier to filter - although there you would just be creeping into LORAN area. Andy G4JNT On 4 June 2015 at 13:17, Chris Wilson wrote: > 04 June 2015 > > > I ordered one of these yesterday as I am getting tired of tying up my > TS-590 just listening on LF. I think a few people here may have used these, > what are your opinions of them please? > > http://icas.to/lineup/idc-136ii-kit-eng.htm > > > > -- > > > Best regards, > Chris mailto:chris@chriswilson.tv > > > --047d7b3a8b3ae5d35f0517b08898 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Haven't seen / played / even heard of them, but we can= get a rough idea of its possible performance just by looking at the pictur= e of the PCB on =C2=A0the web page.=C2=A0 Image filterign is teh biggest pr= oblem with this single conversion route. =C2=A0 Assuming all the image filt= ering is done by those three coils in cans that are visible on the photogra= ph:.

An AADE design for a suitable third order bandpass = filter, with 8kHz bandwidth and allowing a compromise 1dB ripple =C2=A0sugg= ests image rejection at 125kHz will only be around 30dB. =C2=A0 (Top couple= d capacitor =C2=A0design, so low side rejectino is better than high side) = =C2=A0 Not sure what signals are down there to get through, and a highly re= sonant antenna will help a lot more with image rejection - but if its for a= grabber, you're probably going to use a broadband active antenna.

Can't make out much else from the web page photos,= and it give no specification.=C2=A0 But =C2=A0such a simple converter conc= ept can't go hopelessly wrong, if you accept the limited image filter t= hat would be achieved with three tuned circuits

If= I were to try that approach, I'd got for an IF of =C2=A015 - 19kHz, at= the top end of =C2=A0normal soundcard coverage, so bringing the image down= to 105kHz and making it easier to filter - although there you would just b= e creeping into LORAN area.

Andy =C2=A0G4JNT
=

On 4 June 2= 015 at 13:17, Chris Wilson <chris@chriswilson.tv> wrote:<= br>
04 June 2015


I=C2=A0 ordered one of these yesterday as I am getting tired of tying up my=
TS-590 just listening on LF. I think a few people here may have used these,=
what are your opinions of them please?

h= ttp://icas.to/lineup/idc-136ii-kit-eng.htm



--


Best regards,
=C2=A0Chris=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 = =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 mailto:chris@chriswilson.tv



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