Return-Path: Received: from rly-de05.mx.aol.com (rly-de05.mail.aol.com [172.19.170.141]) by air-de03.mail.aol.com (v123.4) with ESMTP id MAILINDE031-4d94a13c15a22f; Wed, 20 May 2009 04:38:15 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-de05.mx.aol.com (v123.4) with ESMTP id MAILRELAYINDE056-4d94a13c15a22f; Wed, 20 May 2009 04:37:48 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1M6hIO-0000PO-63 for rs_out_1@blacksheep.org; Wed, 20 May 2009 09:37:04 +0100 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1M6hIN-0000PF-Js for rsgb_lf_group@blacksheep.org; Wed, 20 May 2009 09:37:03 +0100 Received: from smtp122.mail.mud.yahoo.com ([209.191.84.225]) by relay3.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1M6hIN-0008Mf-31 for rsgb_lf_group@blacksheep.org; Wed, 20 May 2009 09:37:03 +0100 Received: (qmail 92222 invoked from network); 20 May 2009 08:36:55 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btinternet.com; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:Subject:Date:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:X-MIMEOLE; b=wHP1um119wSiJfDD9EAqSWqHLOTluYE3gPH1WgZlBntalX1jLP/+71T+qkIfDEz3E6CU3zDGrNk0jvFX1gNPzjIpo7MRvGcalR3NcZxaUberxNGqHEKGNexzFpMz/CXB3nsKDF4TbF5yKjYhwnK9rhdvg5XF33MeBh1Afwt8uMo= ; Received: from unknown (HELO lindavideo) (ken.h.wright@86.138.91.254 with login) by smtp122.mail.mud.yahoo.com with SMTP; 20 May 2009 08:36:55 -0000 X-YMail-OSG: DhT8k7QVM1nc53zxkXvUmcCrsInFPHBUHjpedITHOl445U4H.ShvsUTYtuvzr0cxCeHx9q6DsRtfew81Lrw.uwIonz5bBZHZVkWMIcP1AbR8OVXkuGHG84R.UMtgs5pb93rUCJTzqhh._EnJTCgyUUeMZfVeEbaJXnGB314gOsU2p1h4uu7F5Qr_TEY5_jOao9gw_4Yg5H4vTeBVlxAyO6EOsAst.vIaG5fm4pca9_I_DlUkJokF8Vw5r2C_rW7pYTRvSs_DOdCMyXzXsTjUSxC_2r2MHOs.CNFAIAXW3xBEbCMhGRbdYNPUT5lI_ZVjo1Ww8xZSghAbYsFiwH4- X-Yahoo-Newman-Property: ymail-3 Message-ID: <117598D055BB4752B434D00FED548617@lindavideo> From: "Ken" To: References: <003001c9d8c4$719e7710$6401a8c0@asus> <20090519232905.l4n0cl7o5vk0oogs@webmail4.kuleuven.be> Date: Wed, 20 May 2009 09:36:53 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 DomainKey-Status: good (testing) Subject: Re: LF: 518khz - Notch Filter. Content-Type: multipart/alternative; boundary="----=_NextPart_000_002C_01C9D92E.821D4890" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.4 required=5.0 tests=FORGED_MUA_OUTLOOK,HTML_30_40, 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-IP: 193.82.116.20 ------=_NextPart_000_002C_01C9D92E.821D4890 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Andy. Where can I obtain a copy of Ansoft Designer from, I usually use Addie for f= ilters, a second option would be worth having. 73 Ken M0KHW=20 ----- Original Message -----=20 From: Andy Talbot=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, May 19, 2009 11:07 PM Subject: Re: LF: 518khz - Notch Filter. Ansoft Designer came up with this solution.=20 http://www.g4jnt.com/518kHz_BandStop.gif The component values aren't particulalrly nice, and there is almost certai= nly a nicer design with transformers to be found, but... Andy G4JNT 2009/5/19 Rik Strobbe Gary, a simple series L-C notch works best when - Q is high =3D you need a good coil (capacitor Q shouldn't be the probl= em) - the output "sees" a high impedance (FET buffer) - the source impedance is high compared to the loss resistance of the co= il (eventualy put a R of a few 100 Ohm in serie with the antenna) But it will be a hard job to get a decent attenuation at 518 while passi= ng 501-506 without too much losses. An alternative would be a xtal filter as a passband filter for 501-506. If you can find a number of 500kHz xtals and "polish" them up some kHz. 73, Rik ON7YD - OR7T=20 Quoting Gary - G4WGT : Hi LF, You may have seen an image of a NAVTEX signal on my 500KHz grabber at=20= about 506KHz. The original of this image is at 518KHz. The receiver for this grabber is a Softrock Lite 455KHz module modified for 500KHz. I have attempted to notch the signal using a simple series or parallel filter but only succeeded in seriously degrading the whole band possib= ly due to the bandwidth of the filter?? Is there some simple narrow notch filter which I could use to remove t= he offending signal. 73, Gary - G4WGT - IO83QP. ------=_NextPart_000_002C_01C9D92E.821D4890 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Andy.
Where can I obtain a copy of Ansoft Designe= r from,=20 I usually use Addie for filters, a second option would be worth=20 having.
 
73
Ken
 
M0KHW 
----- Original Message -----
Andy Talbot
Sent: Tuesday, May 19, 2009 11:07=20 PM
Subject: Re: LF: 518khz - Notch=20 Filter.

Ansoft Designer came up with this solution. 
 
 
The component values aren't particulalrly nice, and there i= s=20 almost certainly a nicer design with transformers to be found, but...

Andy  G4JNT


2009/5/19 Rik Strobbe <Rik.Strobbe@fys.kuleuven.be&= gt;
Gary,

a=20 simple series L-C notch works best when
- Q is high =3D you need a go= od=20 coil (capacitor Q shouldn't be the problem)
- the output "sees" a hig= h=20 impedance (FET buffer)
- the source impedance is high compared to the= =20 loss resistance of the coil (eventualy put a R of a few 100 Ohm in serie= =20 with the antenna)
But it will be a hard job to get a decent attenuati= on=20 at 518 while passing 501-506 without too much losses.

An alternat= ive=20 would be a xtal filter as a passband filter for 501-506.
If you can f= ind=20 a number of 500kHz xtals and "polish" them up some kHz.

73, Rik=20  ON7YD - OR7T=20


Quoting Gary - G4WGT <g4wgt@tiscali.co.uk>:
=
Hi=20 LF,



You may have seen an image of a NAVTEX signal on my= =20 500KHz grabber at about
506KHz. The original of this image is at=20 518KHz. The receiver for this
grabber is a Softrock Lite 455KHz mod= ule=20 modified for 500KHz.



I have attempted to notch the sign= al=20 using a simple series or parallel
filter but only succeeded in=20 seriously degrading the whole band possibly due
to the bandwidth of= the=20 filter??



Is there some simple narrow notch filter which= I=20 could use to remove the
offending=20 signal.



73,



Gary - G4WGT -=20 IO83QP.








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