Return-Path: Received: (qmail 1637 invoked from network); 30 Apr 2002 13:05:48 -0000 Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by exhibition.plus.net with SMTP; 30 Apr 2002 13:05:48 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 7044 invoked from network); 30 Apr 2002 13:05:09 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 30 Apr 2002 13:05:09 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 172Ykq-0002xR-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 30 Apr 2002 15:37:20 +0100 Received: from cmailenv2.svr.pol.co.uk ([213.218.77.54]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 172Ykp-0002xM-00 for rsgb_lf_group@blacksheep.org; Tue, 30 Apr 2002 15:37:19 +0100 Received: from [62.21.145.148] (helo=w8k3f0.freeler.nl) by cmailENV2.svr.pol.co.uk with esmtp (Exim 3.35 #1) id 172XDq-0002lr-00 for rsgb_lf_group@blacksheep.org; Tue, 30 Apr 2002 12:59:11 +0000 Message-ID: <5.1.0.14.0.20020430145204.00a25a60@POP3.freeler.nl> X-Sender: FRE0000086604@POP3.freeler.nl X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Tue, 30 Apr 2002 15:07:15 +0200 To: "LF-Group" From: "Dick Rollema" Subject: LF: Mains QRM blanker by PA0LQ MIME-Version: 1.0 Content-Type: text/html; charset=windows-1252 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Content-transfer-encoding: 8bit To All from PA0SE

Harry, PA0LQ, active on LF until his landlord forbade his aerial, lives in a 12 story apartment block of which corridors are permanently lit by fluorescent tubes. These caused such interference that only very strong signals could be copied. Harry then constructed a blanker that operates on the audio out of the receiver. The blanker can be synchronised to the mains frequency and produces blanking pulses of 50 or 100 Hz. Both width and position of the pulses can be adjusted for optimum blanking. This brought a great improvement in reception.
Harry combined the blanker  with an active 30 Hz bandwidth non-ringing audio filter.

I described both items in our VERON magazine Electron of June 2000.

If there is interest I am willing to translate the text into English and send text and circuit diagram by e-mail to anyone requesting it. Or perhaps it could be placed on a website.
But before taking action I await responses.

73, Dick, PA0SE