Return-Path: <owner-rsgb_lf_group@blacksheep.org>
Received: (qmail 30728 invoked from network); 4 Nov 2002 11:48:25 -0000
Received: from warrior.services.quay.plus.net (212.159.14.227)  by mailstore with SMTP; 4 Nov 2002 11:48:25 -0000
Received: (qmail 14420 invoked from network); 4 Nov 2002 11:47:26 -0000
Received: from post.thorcom.com (193.82.116.70)  by warrior.services.quay.plus.net with SMTP; 4 Nov 2002 11:47:26 -0000
Received: from majordom by post.thorcom.com with local (Exim 4.10) id 188fg0-0004Gh-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 04 Nov 2002 11:45:52 +0000
Received: from [194.73.73.81] (helo=tungsten.btinternet.com) by post.thorcom.com with esmtp (Exim 4.10) id 188ffz-0004GY-00 for rsgb_lf_group@blacksheep.org; Mon, 04 Nov 2002 11:45:51 +0000
Received: from host213-122-9-133.in-addr.btopenworld.com ([213.122.9.133] helo=main) by tungsten.btinternet.com with smtp (Exim 3.22 #8) id 188ffy-0005jy-00 for rsgb_lf_group@blacksheep.org; Mon, 04 Nov 2002 11:45:51 +0000
Message-ID: <003701c283f7$a54f65c0$85097ad5@main>
From: "Alan Melia" <Alan.Melia@btinternet.com>
To: rsgb_lf_group@blacksheep.org
Date: Mon, 4 Nov 2002 11:34:34 -0000
MIME-Version: 1.0
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 4.72.3110.5
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106
Subject: LF: Re: Siemens D2006 Selective Level Meter/Pelelmesser
Content-Type: text/plain; charset=iso-8859-1; format=flowed
Content-Transfer-Encoding: 8bit
X-Spam-Status: No, hits=1.0 required=5.0tests=SPAM_PHRASE_00_01,USER_AGENT_OEversion=2.42
X-Spam-Level: *
Sender: <owner-rsgb_lf_group@blacksheep.org>
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
X-Listname: rsgb_lf_group

Hi all, yes the output from most of these things is the "IF"( and so is from
a carefully designed defined-gain amplifier), there is an Option for the
SPM-12 which is an SSB demodulator. Several LF users have build add-ons to
the standard SPM-12, which has a 10kHz output. It should be possible to use
a chip like the NE602/612 to make a simple demod even at audio frequencies
plus a filter for the image. A relatively simple single pi-section LP filter
with a rejection notch at the image frequency should be adequate for
confortable listening. I did work out the details for the SPM-3  (1.5kHz)
but never built it.

If you want something more sophisticated Zetek have launched a chip with a
mixer and (external component) configurable filter module in it, which is
available from Farnell I believe.....this has a maximum operating frequency
of 600kHz so could even be used as the basis of a simple receiver on 136k.
It was covered in one of the mags (possibly EW) sometime in the last 12
months. I have details somewhere.

Whilst it could work for strong signals, I have my doubts that a divider
chip would be much use with weak signals and lots of noise. Dividers are
used in Bat Detectors, but mixer versions are much better......the bat
conservationists are finding that soundcard DSP programs, like Spectrogram,
are helping them to identify individual bats !! I suppose that is the sort
of thing Robert originally wrote it for !!

Cheers de Alan G3NYK
alan.melia@btinternet.com
-----Original Message-----
From: jan-martin.noding@telenor.com <jan-martin.noding@telenor.com>
To: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org>
Date: 04 November 2002 08:14
Subject: LF: Siemens D2006 Selective Level Meter/Pelelmesser


Hi

Does somebody know if it is possible to change the pitch?
It has 80Hz as well as 3100Hz bandwidth, but the pitch is ca
1000Hz and not too pleasant to listen to, would rather prefer 500Hz

73,
Jan_Martin