Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 365703800008D; Sat, 28 Apr 2012 05:44:51 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SO4BW-0002Jh-1S for rs_out_1@blacksheep.org; Sat, 28 Apr 2012 10:43:22 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SO4BV-0002JY-AV for rsgb_lf_group@blacksheep.org; Sat, 28 Apr 2012 10:43:21 +0100 Received: from imr-da03.mx.aol.com ([205.188.105.145]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1SO4BS-0003gy-U7 for rsgb_lf_group@blacksheep.org; Sat, 28 Apr 2012 10:43:20 +0100 Received: from mtaout-db03.r1000.mx.aol.com (mtaout-db03.r1000.mx.aol.com [172.29.51.195]) by imr-da03.mx.aol.com (8.14.1/8.14.1) with ESMTP id q3S9hEex017129 for ; Sat, 28 Apr 2012 05:43:14 -0400 Received: from White (nrbg-4dbf1670.pool.mediaWays.net [77.191.22.112]) by mtaout-db03.r1000.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id E7606E000090 for ; Sat, 28 Apr 2012 05:43:10 -0400 (EDT) Message-ID: <7D6E3A8750EA44C5A4343E7D8E84BC32@White> From: "Markus Vester" To: References: <4F981FFA.20201@freenet.de> <4F98254C.9050300@iup.uni-heidelberg.de> <4F982D4A.50405@freenet.de> <92C055C51C18431AAC57B494216C5E2F@Extensa> <9EDCCC1902C640C695BF491F98858756@Extensa> Date: Sat, 28 Apr 2012 11:43:09 +0200 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 12.0.1606 X-MimeOLE: Produced By Microsoft MimeOLE V12.0.1606 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20110426; t=1335606194; bh=sXqew2WVLOG1xt/hqlF89Kzhzw62ZcaSUb1+r0IxDog=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=ku1IBLl4/+c6iOIZ3bp1/HcXby7OVGD8Bmu1elbruqMzdoeRWzHUkzjzscRcCnSqn tQz0tayGQxF/qg/K3F10WAzTpCaNEPdeqFcGkbZlomGryF6pPW7uYahisgJN7lYCoF pqxghvr2Z6LslFGcabzgRQQ+vOiL3+UOz5XDC7EU= X-AOL-SCOLL-SCORE: 0:2:399609888:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Perhaps another hardware option: a recent QEX article from W6EAW mentioned the use of an FE-5680A Rubidium source, which contains a programmable AD9830 DDS chip. A number of these have become available second hand by several Chinese sellers for around 70 - 100$. The " 1Hz-20MHz" (option 02) version has the RS-232 serial interface brought to the external 9-pin connector, but according to Matthias Bopp http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%200_9.pdf this can also be retrofitted for the standard fixed-10MHz version. I have ordered one of the programmable units, and when it arrives I will attempt to generate LF and VLF signals directly from the output. [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [205.188.105.145 listed in list.dnswl.org] 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (markusvester[at]aol.com) -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid X-Scan-Signature: 118b9e608370528226a3c3b3aedcdda0 Subject: Re: LF: Generating 8970 Hz carrier... - programmable Rb source Content-Type: multipart/alternative; boundary="----=_NextPart_000_0021_01CD2534.15B67AA0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,HTML_MESSAGE, MISSING_OUTLOOK_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 x-aol-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:455361504:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d310.2 ; domain : mx.aol.com DKIM : pass x-aol-sid: 3039ac1d600e4f9bbc136ae3 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Dies ist eine mehrteilige Nachricht im MIME-Format. ------=_NextPart_000_0021_01CD2534.15B67AA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Perhaps another hardware option: a recent QEX article from W6EAW = mentioned the use of an FE-5680A Rubidium source, which contains a = programmable AD9830 DDS chip. A number of these have become available = second hand by several Chinese sellers for around 70 - 100$. The " = 1Hz-20MHz" (option 02) version has the RS-232 serial interface brought = to the external 9-pin connector, but according to Matthias Bopp = http://www.dd1us.de/Downloads/precise%20reference%20frequency%20rev%200_9= .pdf=20 this can also be retrofitted for the standard fixed-10MHz version. I = have ordered one of the programmable units, and when it arrives I will = attempt to generate LF and VLF signals directly from the output. Note that though Rb oscillators provide excellent stability and = reproducability (better than 1e-10), they still need to be calibrated to = achieve absolute frequency accuracy. =20 Best 73, Markus (DF6NM) ------=_NextPart_000_0021_01CD2534.15B67AA0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Perhaps another=20 hardware option: a recent QEX article from W6EAW mentioned the use of an = FE-5680A Rubidium source, which contains a programmable AD9830 DDS chip. = A=20 number of these have become available second hand by several = Chinese=20 sellers for around 70 - 100$. The " 1Hz-20MHz" (option 02) version has = the=20 RS-232 serial interface brought to the external 9-pin connector, = but=20 according to Matthias Bopp
 http://www.dd1us.de/Downloads/precise%20reference%20frequen= cy%20rev%200_9.pdf=20
this can also be retrofitted for = the standard=20 fixed-10MHz version. I have ordered one of the programmable units, = and when=20 it arrives I will attempt to generate LF and VLF signals directly from = the=20 output.
 
Note that though Rb = oscillators provide=20 excellent stability and reproducability (better than 1e-10), they=20 still need to be calibrated to achieve absolute frequency=20 accuracy.  
 
Best 73,
Markus (DF6NM)
 
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