Return-Path: X-Spam-DCC: paranoid 1233; Body=3 Fuz1=3 Fuz2=3 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.1 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_40_50,HTML_BACKHAIR_8,HTML_MESSAGE,HTML_OBFUSCATE_05_10 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 t54DIsg1022230 for ; Thu, 4 Jun 2015 15:18:54 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Z0V0S-00074y-S2 for rs_out_1@blacksheep.org; Thu, 04 Jun 2015 14:16:24 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Z0V0S-00074o-FR for rsgb_lf_group@blacksheep.org; Thu, 04 Jun 2015 14:16:24 +0100 Received: from mail-wi0-f174.google.com ([209.85.212.174]) by relay1.thorcom.net with esmtps (TLSv1.2:AES128-GCM-SHA256:128) (Exim 4.85) (envelope-from ) id 1Z0V0Q-0008F3-AJ for rsgb_lf_group@blacksheep.org; Thu, 04 Jun 2015 14:16:23 +0100 Received: by wifw1 with SMTP id w1so58234614wif.0 for ; Thu, 04 Jun 2015 06:16:21 -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=pBx52HvChTymPChqxfEH5ZgABpTIbsFiAUZQR8RAfGY=; b=uGeQ4N6A8IMJsV8qrjvMDNmwnm/PaLCYbUMTRtAsnjf/em9eZAAz9t90//wEio6SUT KgYQ/CpQNSpMslWWHKazu/5J7uWCqrd3k+NLHEGN+5ef5uwQSHMhbLnKMzo4R59vBK39 UEhF5oq4PRfVZniYtE/WXGfNxJLjXs289jbasa4BVqJ+s780JZC1Q7C8rguKxtchvbYW 0yhhHECU91WPOQS/80M6RMOYU87LPj9ASGyCgGi388Ww39sCmUGbxzYwk7X3FzApf87r brl5M95xzPfvqK9mCxg+jDxe8zYo3H3YT1H+S/+wwWhgbmMSBPjVEOuLdtAAKPCIY/Pw cUWw== MIME-Version: 1.0 X-Received: by 10.180.189.209 with SMTP id gk17mr1440532wic.93.1433423781356; Thu, 04 Jun 2015 06:16:21 -0700 (PDT) Received: by 10.28.136.132 with HTTP; Thu, 4 Jun 2015 06:16:21 -0700 (PDT) In-Reply-To: <7E7DFBB4D102A04DB5ADC88D66628A4A235626A6@ICTS-S-MBX1.luna.kuleuven.be> References: <1052531792.20150604131722@chriswilson.tv> <7E7DFBB4D102A04DB5ADC88D66628A4A235626A6@ICTS-S-MBX1.luna.kuleuven.be> Date: Thu, 4 Jun 2015 14:16:21 +0100 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org X-Scan-Signature: 40d35b6fcf8b66e4fec28fa30f99f125 Subject: Re: LF: IDC-136-BLT 136kHz receivers Content-Type: multipart/alternative; boundary=001a11c34ef64ced4d0517b0fb81 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: 3435 --001a11c34ef64ced4d0517b0fb81 Content-Type: text/plain; charset=UTF-8 AH, thanks for finding that - must have missed it on first looking. Yes I agree, the NE612 is a poor mixer to use for those purposes. A diode ring, or bus switch would do a muxch better job But why not an I/Q conversion and make use of all the decent SDR software out there? Andy G4JNT On 4 June 2015 at 14:05, Rik Strobbe wrote: > Hello Andy, Chris, > > > > the circuit diagram can be found in this PDF: http://icas.to > > /idc-136ii/idc-136ii-kit-manual-eng.pdf > > > In contradiction to the block diagram at http://icas.to > /lineup/idc-136ii-kit-eng.htm > the circuit diagram > show a J310 wideband preamp before the BPF. > > I have played with SA612 chip in the past and found that it had rather > poor IMD behaviour compared to a 74HC4053 mixer. > > > > 73, Rik ON7YD - OR7T > > > ------------------------------ > *Van:* owner-rsgb_lf_group@blacksheep.org [ > owner-rsgb_lf_group@blacksheep.org] namens Andy Talbot [ > andy.g4jnt@gmail.com] > *Verzonden:* donderdag 4 juni 2015 14:44 > *Aan:* rsgb_lf_group@blacksheep.org > *Onderwerp:* Re: LF: IDC-136-BLT 136kHz receivers > > 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 >> >> >> > --001a11c34ef64ced4d0517b0fb81 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
AH, thanks for finding that - must have missed it on first= looking.
Yes I agree, the NE612 is a poor mixer to use for those purpo= ses. =C2=A0 A diode ring, or bus switch would do a muxch better job

But why not an I/Q conversion and make use of all the dec= ent SDR software out there? =C2=A0=C2=A0

Andy =C2= =A0G4JNT



On 4 June 2015 at 14:05, Rik Strobbe <Rik.Strobbe@fys.kuleuven.be> wrote:

Hello=C2=A0Andy, Chris,

=C2=A0

the circuit diagram=C2=A0can=C2=A0be=C2=A0found in= =C2=A0this PDF: http://icas.to/idc-136ii/idc-136ii-kit-manual-= eng.pdf

In=C2=A0contradiction to the=C2=A0block diagram at h= ttp://icas.to/lineup/idc-136ii-kit-eng.htm=C2=A0the circuit d= iagram show=C2=A0a=C2=A0J310=C2=A0wideband=C2=A0preamp= =C2=A0before the BPF.

I have=C2=A0played=C2=A0with=C2=A0SA612 chip= in the past and=C2=A0found=C2=A0that=C2=A0it had=C2= =A0rather=C2=A0poor=C2=A0IMD=C2=A0behaviour<= /a>=C2=A0compared to a=C2=A074HC4053 mixer.

=C2=A0

73,=C2=A0Rik=C2=A0=C2=A0ON7YD - OR7T<= /p>

=C2=A0

Van: owner-rsgb_lf_group@blacksheep.org [owner-rsgb_lf_group@blac= ksheep.org] namens Andy Talbot [andy.g4jnt@gmail.com]
Verzonden: donderdag 4 juni 2015 14:44
Aan: rsgb_lf_group@blacksheep.org
Onderwerp: Re: LF: IDC-136-BLT 136kHz receivers

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 filtering is done by those three coils in cans that are visi= ble on the photograph:.

An AADE design for a suitable third order bandpass filter, with 8kHz b= andwidth and allowing a compromise 1dB ripple =C2=A0suggests image rejectio= n at 125kHz will only be around 30dB. =C2=A0 (Top coupled capacitor =C2=A0d= esign, so low side rejectino is better than high side) =C2=A0 Not sure what signals are down there to get through, and a hi= ghly resonant antenna will help a lot more with image rejection - but if it= s for a grabber, you're probably going to use a broadband active antenn= a.

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

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

Andy =C2=A0G4JNT

On 4 June 2015 at 13:17, Chris Wilson <chri= s@chriswilson.tv> wrote:
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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