Return-Path: Received: from rly-mf06.mx.aol.com (rly-mf06.mail.aol.com [172.20.29.176]) by air-mf02.mail.aol.com (v121.4) with ESMTP id MAILINMF022-9634787b99a208; Fri, 11 Jan 2008 13:47:06 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-mf06.mx.aol.com (v121.4) with ESMTP id MAILRELAYINMF061-9634787b99a208; Fri, 11 Jan 2008 13:46:52 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1JDOsf-0006oo-2i for rs_out_1@blacksheep.org; Fri, 11 Jan 2008 18:45:25 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1JDOse-0006of-Jn for rsgb_lf_group@blacksheep.org; Fri, 11 Jan 2008 18:45:24 +0000 Received: from fk-out-0910.google.com ([209.85.128.189]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1JDOsa-00019Q-Bs for rsgb_lf_group@blacksheep.org; Fri, 11 Jan 2008 18:45:24 +0000 Received: by fk-out-0910.google.com with SMTP id 18so997690fks.4 for ; Fri, 11 Jan 2008 10:45:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:to:subject:mime-version:content-type; bh=Ecipy6vFc9gdeimMVhxHrg7Wj+nOUdHsuznICV0HAJQ=; b=b7SW6pdlebOt0SbbyHfjfLvv9Asamy7nZgCMtDTQB5mzI0RIhoHooBHp/k5MUJXTJ4LYLxpCZD6W7lwzDNnk8kOqlQgxeMeDUB6yXBm8FgvVFJ/sPf4yFYofqQYa2+MvWnKmm9QUA+PLk3WckgeBxJVhEChqvPqXqIIfGIIVhIA= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=message-id:date:from:to:subject:mime-version:content-type; b=EcXctOUjyqAXCGtlEslabMKWU/5Xrll+KZqiSWc/WQw+8eJ1lBxZ9nF+YvSuK/AFvBQyV5ikNygPdhQt2zZldvMXge6cj7URm8LkNRxKvfT/ZXPzHjv4BjoEuVBd3Mq3shhZ0nQ6U/zSrgzTuhFHIoHhrau9jqcrKUEHdHuhlXM= Received: by 10.78.200.20 with SMTP id x20mr4350254huf.43.1200077119454; Fri, 11 Jan 2008 10:45:19 -0800 (PST) Received: by 10.78.205.4 with HTTP; Fri, 11 Jan 2008 10:45:19 -0800 (PST) Message-ID: <88d2415e0801111045t1e31ee78vbaf955f4f2a9f3a8@mail.gmail.com> Date: Fri, 11 Jan 2008 18:45:19 +0000 From: "lawrence mayhead" To: rsgb MIME-Version: 1.0 DomainKey-Status: good (testing) X-Spam-Score: 0.6 (/) X-Spam-Report: autolearn=disabled,HTML_00_10=0.642,HTML_MESSAGE=0.001 Subject: LF: LF Receiver Content-Type: multipart/alternative; boundary="----=_Part_2697_19092860.1200077119450" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=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 X-AOL-SCOLL-AUTHENTICATION: listenair ; SPF_helo : n X-AOL-SCOLL-AUTHENTICATION: listenair ; SPF_822_from : ? X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m109.1 ; domain : googlemail.com DKIM = 3 X-Mailer: Unknown (No Version) ------=_Part_2697_19092860.1200077119450 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline I have for a long time used a Racal 1792 reciever for QRSS modes on LF. This receiver failed recently,and I have been looking for a replacement receiver. This search reveals a problem most modern receivers use DSP techniques for filtering and the AGC is derived from the filtered signal. None of the receivers I have looked at have an AGC OFF facility.This means that if one of these receivers is used with ARGO or similar FFT programs a strong signal within the pass band will desensitise the Rx. It seems quite possible that a weak signal could quite disapear. It also appears that some AGC is applied before the digital filter so that signals within the roofing filters bandwith will also produce de-sensitisation, and this could be as much as 15kHz away from the tune freq. Any ideas on receivers not using DSP filtering ? Or do I look for another R1792 73 Laurie G3AQC ------=_Part_2697_19092860.1200077119450 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline I have for a long time used a Racal 1792 reciever for QRSS modes on LF.
This receiver failed recently,and I have been looking for a replacement receiver.
This search reveals a problem most modern receivers use DSP techniques
for filtering and the AGC is derived from the filtered signal. None of the receivers
I have looked at have an AGC OFF  facility.This means that if one of these receivers
is used with ARGO or similar FFT programs a strong signal within the pass band
will desensitise the Rx. It seems quite possible that a weak signal could quite
disapear. It also appears that some AGC is applied before the digital filter so that
signals within the roofing filters bandwith will also produce de-sensitisation, and this
could be as much as 15kHz away from the tune freq.
Any ideas on receivers not using DSP filtering ?
Or do I look for another R1792   

73 Laurie G3AQC
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