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[82.70.254.222]) by smtp.gmail.com with ESMTPSA id t14sm6569165wmc.23.2018.02.12.08.55.42 for (version=TLS1 cipher=AES128-SHA bits=128/128); Mon, 12 Feb 2018 08:55:42 -0800 (PST) Date: Mon, 12 Feb 2018 16:47:00 +0000 From: Chris Wilson X-Priority: 3 (Normal) Message-ID: <212280367.20180212164700@gmail.com> To: rsgb_lf_group@blacksheep.org In-Reply-To: <5A81C025.13685.51C8EA38@mike.dennison.ntlworld.com> References: <1125097296.20180212141115@gmail.com> <5A81C025.13685.51C8EA38@mike.dennison.ntlworld.com> MIME-Version: 1.0 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has NOT identified this incoming email as spam. The original message has been attached to this so you can view it or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hello Mike, I just listened to what looks like the AM modulated bursts around 139 and 135.5 kHz and they sound like bursts of data, nothing intelligible whatsoever. Monday, February 12, 2018, 4:26:13 PM, you wrote: [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (dead.fets[at]gmail.com) 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 5c335215f1b3de26d890ee84d49616ce Subject: Re: LF: Do I need an attenuator on LF RX?? Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=PRIORITY_NO_NAME 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 Hello Mike, I just listened to what looks like the AM modulated bursts around 139 and 135.5 kHz and they sound like bursts of data, nothing intelligible whatsoever. Monday, February 12, 2018, 4:26:13 PM, you wrote: > Chris, > It looks like you have a broadcast station where it shouldn't be (at > 132.65kHz) and several other spurious stations in that area, so you > may well have unwanted signals within the 136kHz band, especially at > night (your recording seems to have been done during the middle of > the day). You might improve things by by-passing the pre-amp. It > would do no harm just by experimenting with an attenuator but why > attenuate and amplify at the same time unless the preamp also > provides another function such as matching? It seems the only > front-end selectivity on that receiver is a narrow bandpass so you > would really benefit from some additional wider filtering, eg an LPF > with a cut-off just below the LW BC band. > Mike, G3XDV -- Best regards, Chris mailto:dead.fets@gmail.com