Return-Path: Received: (qmail 18814 invoked from network); 30 Apr 2002 17:20:08 -0000 Received: from unknown (HELO murphys-inbound.services.quay.plus.net) (212.159.14.225) by excalibur.plus.net with SMTP; 30 Apr 2002 17:20:08 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 25968 invoked from network); 30 Apr 2002 16:10:45 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by murphys.services.quay.plus.net with SMTP; 30 Apr 2002 16:10:45 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 172ame-0003Nm-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 30 Apr 2002 17:47:20 +0100 Received: from nat5.excitenetwork.com ([63.236.75.7] helo=xmxpita.excite.com) by post.thorcom.com with esmtp (Exim 3.33 #2) id 172amd-0003NY-00 for rsgb_lf_group@blacksheep.org; Tue, 30 Apr 2002 17:47:19 +0100 Received: by xmxpita.excite.com (Postfix, from userid 110) id 2415B3E78; Tue, 30 Apr 2002 11:08:43 -0400 (EDT) To: rsgb_lf_group@blacksheep.org Subject: RE: LF: Mains QRM blanker by PA0LQ Received: from [62.253.64.8] by xprdmailfe8.nwk.excite.com via HTTP; Tue, 30 Apr 2002 11:08:43 EST From: "john sexton" MIME-Version: 1.0 X-Sender: computernetworks@excite.com X-Mailer: PHP Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: 8bit Message-ID: <20020430150843.2415B3E78@xmxpita.excite.com> Date: Tue, 30 Apr 2002 11:08:43 -0400 (EDT) Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Hi Dick,
The noise blanker is of interest here.
I find Spectran an excellent tool for providing the second item, the very narrow adjustable non-ringing audio filter. On its own it removes practically all of the noise.
73, John, G4CNN

--- On Tue 04/30, Dick Rollema wrote:
>
> 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
>