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=-0.5 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_50_60,HTML_MESSAGE,RATWARE_GECKO_BUILD 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 t54DG3fF022208 for ; Thu, 4 Jun 2015 15:16:03 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Z0UxG-0006zg-T2 for rs_out_1@blacksheep.org; Thu, 04 Jun 2015 14:13:06 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Z0UxG-0006zX-G1 for rsgb_lf_group@blacksheep.org; Thu, 04 Jun 2015 14:13:06 +0100 Received: from mailfe07.swip.net ([212.247.154.193] helo=swip.net) by relay1.thorcom.net with esmtp (Exim 4.85) (envelope-from ) id 1Z0UxE-0008Cs-Bp for rsgb_lf_group@blacksheep.org; Thu, 04 Jun 2015 14:13:05 +0100 X-T2-Spam-Status: No, hits=0.9 required=5.0 tests=BAYES_50, HTML_MESSAGE Received: from [81.227.25.191] (account cxu-dcw-tyr@tele2.se HELO [192.168.1.4]) by mailfe07.swip.net (CommuniGate Pro SMTP 5.4.4) with ESMTPSA id 600417444 for rsgb_lf_group@blacksheep.org; Thu, 04 Jun 2015 15:13:01 +0200 Message-ID: <55704EE0.9020102@tele2.se> Date: Thu, 04 Jun 2015 15:13:04 +0200 From: Johan Bodin User-Agent: Mozilla/5.0 (Windows NT 6.3; WOW64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <1052531792.20150604131722@chriswilson.tv> In-Reply-To: X-HELO-Warning: Remote host 212.247.154.193 (mailfe07.swip.net) used invalid HELO/EHLO swip.net - verification failed X-Scan-Signature: 29f208b223fe7a2cb359508e38e2ea2d Subject: Re: LF: IDC-136-BLT 136kHz receivers Content-Type: multipart/alternative; boundary="------------050008000703010502010506" 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: 3434 This is a multi-part message in MIME format. --------------050008000703010502010506 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit There is a schematic diagram and a BOM in the assembly manual: http://icas.to/idc-136ii/idc-136ii-kit-manual-eng.pdf 73 Johan SM6LKM Andy Talbot skrev den 2015-06-04 14:44: > 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 > > > > --------------050008000703010502010506 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit There is a schematic diagram and a BOM in the assembly manual: http://icas.to/idc-136ii/idc-136ii-kit-manual-eng.pdf
73
Johan SM6LKM

Andy Talbot skrev den 2015-06-04 14:44:
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 <chris@chriswilson.tv> 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




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