Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dl06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 77CCE380000BF; Sun, 7 Aug 2011 19:03:11 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QqCMU-0008Gp-4J for rs_out_1@blacksheep.org; Mon, 08 Aug 2011 00:02:26 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QqCMT-0008Gg-L0 for rsgb_lf_group@blacksheep.org; Mon, 08 Aug 2011 00:02:25 +0100 Received: from imr-ma03.mx.aol.com ([64.12.206.41]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QqCMQ-0001VH-UI for rsgb_lf_group@blacksheep.org; Mon, 08 Aug 2011 00:02:25 +0100 Received: from mtaout-da06.r1000.mx.aol.com (mtaout-da06.r1000.mx.aol.com [172.29.51.134]) by imr-ma03.mx.aol.com (8.14.1/8.14.1) with ESMTP id p77N2Ik3026001 for ; Sun, 7 Aug 2011 19:02:18 -0400 Received: from White (nrbg-4d057a10.pool.mediaWays.net [77.5.122.16]) by mtaout-da06.r1000.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id B5BBAE000188 for ; Sun, 7 Aug 2011 19:02:15 -0400 (EDT) Message-ID: From: "Markus Vester" To: References: <4E3B1BFD.5090807@iup.uni-heidelberg.de> <4E3B2EA3.90003@iup.uni-heidelberg.de> <26D9EBB1476B467E9E02C10B3FACC2C8@PcMinto> <4E3D54DE.1000202@iup.uni-heidelberg.de> <5D042DA2B0C04AA09C5416113128574C@PcMinto> <4E3E614D.3060409@iup.uni-heidelberg.de> <4E3EBF3F.6090604@iup.uni-heidelberg.de> <4E3F03BA.5020707@iup.uni-heidelberg.de> Date: Mon, 8 Aug 2011 01:02:22 +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 X-AOL-SCOLL-SCORE: 0:2:455988000:93952408 X-AOL-SCOLL-URL_COUNT: 0 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: Re: CW sked on 137 friday morning? Content-Type: multipart/alternative; boundary="----=_NextPart_000_0014_01CC5566.D4306BB0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_40_50,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: 0:2:484754688:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d4ad44e3f19ae506a 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_0014_01CC5566.D4306BB0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Hi Minto,=20 you could overcome the dynamic range limitation of the measurement by = using an attenuator for the signal measurement. 1. tune to the center of the LF band, with DCF39 outside the passband. = Turn up the gain control as much as needed. Read the noise level in = SpecLab. 2. tune to 138.83 kHz. Insert a 40 dB attenuator but don't change the = gain. Read only the signal level (and ignore the noise).=20 To obtain DCF39 SNR, simply subtract noise level (1) from signal level = (2), and add 40 dB. In my location at 320 km from Magdeburg, DCF39 is normally about 3 mV/m = (70 dBuV/m). The best-case band noise has been down to about 0.06 uV/m = in 1 Hz (-25 dBuV/m/sqrtHz). Thus SNR can be up to 95 dB in 1 Hz here. DCF39 is said to have 40 kW EMRP. Thus a 1 W ERP amateur station at the = same distance would be 49 dB weaker. Best 73,. Markus (DF6NM) From: Minto Witteveen=20 Sent: Monday, August 08, 2011 12:20 AM To: rsgb_lf_group@blacksheep.org=20 Subject: LF: Re: CW sked on 137 friday morning? Hi Stefan, Let me try to explain a bit better what I have done. When I disable the = AGC of the FT897 I need to dial-down the manual AGC in order to avoid = overloading the IF AND the AF sections when tuned to DCF39. (If I = don=E2=80=99t DCF39 sounds horribly distorted). With this setting I = measure the LF output of the 879 with Speclab. With the same manual AGC setting I tune to say 137.700 and measure the = LF output again with Speclab. But because the manual AGC is dialed down = significantly the band noise =E2=80=98drops through=E2=80=99 the noise = floor of the FT897. So this method is unusable to determine the strenght = of DCF39 w.r.t. to the noise. If I dial up the AGC (or set it on auto again) the noise floor increases = with about 10 dB when I connect the antenna, I think this should be = enough.. By the way, this moment I can not only see your CQ with Speclab, but = with headphones I can even hear you. Regards, Minto pa3bca ... ------=_NextPart_000_0014_01CC5566.D4306BB0 Content-Type: text/html; charset="utf-8" Content-Transfer-Encoding: quoted-printable
Hi Minto,
 
you could overcome the dynamic range = limitation of=20 the measurement by using an attenuator for the signal = measurement.
 1. tune to the center of the = LF band,=20 with DCF39 outside the passband. Turn up the gain control as much = as=20 needed. Read the noise level in SpecLab.
 2. tune to 138.83 kHz. = Insert a 40 dB=20 attenuator but don't change the gain. Read only the signal level = (and=20 ignore the noise). 
To obtain DCF39 SNR, = simply=20 subtract noise level (1) from signal level (2), and add = 40=20 dB.
 
In my location at 320 km from Magdeburg, DCF39 = is normally=20 about 3 mV/m (70 dBuV/m). The best-case band noise has = been down=20 to about 0.06 uV/m in 1 Hz (-25 dBuV/m/sqrtHz). Thus SNR can be up = to 95 dB=20 in 1 Hz here.
 
DCF39 is said to have 40 kW EMRP. = Thus a 1 W ERP=20 amateur station at the same distance would be 49 dB = weaker.
Best 73,.
Markus (DF6NM)
 
From: Minto Witteveen
Sent: Monday, August 08, 2011 12:20 AM
To: rsgb_lf_group@blacksheep.org= =20
Subject: LF: Re: CW sked on 137 friday = morning?

Hi = Stefan,

Let me try to explain a = bit better=20 what I have done. When I disable the AGC of the FT897 I need to = dial-down the=20 manual AGC in order to avoid overloading the IF AND the AF sections when = tuned=20 to DCF39. (If I don=E2=80=99t  DCF39 sounds=20 horribly distorted). With this setting I measure the LF output of the = 879 with=20 Speclab.
With the same manual AGC setting I tune to say 137.700 and = measure=20 the LF output again with Speclab. But because the manual AGC is dialed = down=20 significantly the band noise =E2=80=98drops through=E2=80=99 the noise = floor of the FT897. So=20 this method is unusable to determine the strenght of DCF39 w.r.t. to the = noise.

If I dial up the AGC (or = set it on=20 auto again) the noise floor increases with about 10 dB when I connect = the=20 antenna, I think this should be enough..

By the way, this moment I = can not=20 only see your CQ with Speclab, but with headphones I can even hear=20 you.

Regards,
Minto=20 pa3bca

 ...=20
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