Return-Path: Received: from mtain-mc05.r1000.mx.aol.com (mtain-mc05.r1000.mx.aol.com [172.29.96.77]) by air-df06.mail.aol.com (v126.13) with ESMTP id MAILINDF064-5ef94b48f634bc; Sat, 09 Jan 2010 16:33:40 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mc05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 851EF3800016A; Sat, 9 Jan 2010 16:33:37 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NTivP-0000g9-0V for rs_out_1@blacksheep.org; Sat, 09 Jan 2010 21:32:47 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NTivO-0000fz-J2 for rsgb_lf_group@blacksheep.org; Sat, 09 Jan 2010 21:32:46 +0000 Received: from imr-ma02.mx.aol.com ([64.12.206.40]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NTivM-0001Di-BQ for rsgb_lf_group@blacksheep.org; Sat, 09 Jan 2010 21:32:46 +0000 Received: from imo-ma04.mx.aol.com (imo-ma04.mx.aol.com [64.12.78.139]) by imr-ma02.mx.aol.com (8.14.1/8.14.1) with ESMTP id o09LWP8a017897; Sat, 9 Jan 2010 16:32:25 -0500 Received: from MarkusVester@aol.com by imo-ma04.mx.aol.com (mail_out_v42.5.) id l.cbf.530fe84f (34982); Sat, 9 Jan 2010 16:32:23 -0500 (EST) Received: from Black (g229072103.adsl.alicedsl.de [92.229.72.103]) by cia-da08.mx.aol.com (v127.7) with ESMTP id MAILCIADA087-88a64b48f5e5f6; Sat, 09 Jan 2010 16:32:22 -0500 Message-ID: <18E5344EFE6C4DA9870B8B28EEAE10B2@Black> From: "Markus Vester" To: Cc: Date: Sat, 9 Jan 2010 22:32:20 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6000.16480 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6000.16669 X-Spam-Flag:NO X-AOL-SENDER: MarkusVester@aol.com X-Karma: unknown: X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: LF on Twente Web-SDR Content-Type: multipart/alternative; boundary="----=_NextPart_000_000E_01CA917B.9B31AF50" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: ** X-Spam-Status: No, hits=2.5 required=5.0 tests=HTML_20_30,HTML_MESSAGE, MISSING_OUTLOOK_NAME,WEIRD_PORT 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-global-disposition: G x-aol-sid: 3039ac1d604d4b48f6315c2b X-AOL-IP: 193.82.116.20 ------=_NextPart_000_000E_01CA917B.9B31AF50 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Dear LF group, recently I found that the excellent 7-band web receiver at Twente Univ= ersity http://websdr.ewi.utwente.nl:8901/ also features a low frequenc= y section (64 to 164 kHz). In contrast to the situation a few months= ago, the LF band now appears to be completely cleared of local interf= erence, and the receiver is quite sensitive. By connecting the PC's audio output to the line input by a "real" phys= ical audio cable, I was able to perfectly read 137 kHz QRSS3 signals= on a slow spectrogram. The audio resampling process from nominal 8438= Hz samplerate does introduce up to +- 0.2% of samplerate variation,= but the resulting frequency instability can be mitigated by tuning to= a low beat frequency (eg. about 300 Hz). The digital IF bandpass skir= ts can be pulled in as required. Using WSPR v2 with an appropriate Rx-= BFO setting, it was possible to successfully decode WSPR signals that= way as well. The web-SDR waterfall also shows a strong Loran-C spectrum around 100= kHz (mostly from Sylt, 300 km from Enschede). This tempted me to feed= its output to my "LoranView" averaging program. With samplerate track= ing to the Sylt pulses and five minute averaging, I could detect trace= s from 48 different Loran stations last night, including far away ones= like Port Clarence (Alaska), Raymondville (Texas) and Gesashi (Japan,= 9582 km). Many thanks to Pieter-Tjerk PA3FWM, for providing us with this outstan= ding peace of work! 73, Markus (DF6NM) ------=_NextPart_000_000E_01CA917B.9B31AF50 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Dear LF group,
 
recently I found that the excell= ent 7-band web=20 receiver at Twente University = http://websdr.ewi.utw= ente.nl:8901/ also featu= res a low frequency section (64=20 to 164 kHz). In contrast to the situation a few months ago, the LF&nbs= p;band now=20 appears to be completely cleared of local interference, and = the=20 receiver is quite sensitive.
 
By connecting the PC's audio&nbs= p;output to=20 the line input by a "real" physical audio cable, I was able to pe= rfectly=20 read 137 kHz QRSS3 signals on a slow spectrogram. The audio= resampling=20 process from nominal 8438 Hz samplerate does=20 introduce up to +- 0.2% of samplerate variation, but the resulting fre= quency=20 instability can be mitigated by tuning to a low beat frequency (e= g. about=20 300 Hz). The digital IF bandpass skirts can be pulled in as required.= Using WSPR=20 v2 with an appropriate Rx-BFO setting, it was possible to success= fully=20 decode WSPR signals that way as well.
 
The web-SDR waterfall also shows = ;a strong=20 Loran-C spectrum around 100 kHz (mostly from Sylt, 300 km from En= schede).=20 This tempted me to feed its output to my "LoranView" av= eraging=20 program. With samplerate tracking to the Sylt puls= es and=20 five minute averaging, I could detect traces from 48 different Lo= ran=20 stations last night, including far away ones like Port Clarence (Alask= a),=20 Raymondville (Texas) and Gesashi (Japan, 9582 km).
 
Many thanks to Pieter-Tjerk PA3FWM,= for providing=20 us with this outstanding peace of work!
 
73,
Markus (DF6NM)
 
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