Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id wACNAZwh029526 for ; Tue, 13 Nov 2018 00:10:36 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1gMLE2-0005Ku-SC for rs_out_1@blacksheep.org; Mon, 12 Nov 2018 23:02:34 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1gMLC7-0005KM-LG for rsgb_lf_group@blacksheep.org; Mon, 12 Nov 2018 23:00:35 +0000 Received: from sonic301-4.consmr.mail.bf2.yahoo.com ([74.6.129.43]) by relay1.thorcom.net with esmtp (Exim 4.91_59-0488984) (envelope-from ) id 1gMLC1-00037M-7n for rsgb_lf_group@blacksheep.org; Mon, 12 Nov 2018 23:00:30 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=aol.com; s=a2048; t=1542063627; bh=e9mIK5kLxNn96iOwDQHqm/bgt+mS+FgLyyDPkAex8Fg=; h=Date:From:To:Subject:References:From:Subject; b=ALWKpUD0tWiQuR8ybvqTgClrY7L0sF08iyi+x5XC9TLbqaUnwgUcRPXrSSQS8e33VbHIP81p9dT8viaVEcabzBegvLZrcdTLJ6OdTstoJDoMhVqgAK9iFtdf3B2hhCQ/7ECoQQQLEm0eFYLkFR890CBxNT4ipqt+SJ+uQSNW2hYAoXjIhV75Qce7EbNOj/gPkMfawR7UlSabJniTvrCuS5NIak7Rl6W+UTcAvZ0+7LqOu/MnKVSBueIxEw6hQDS/fQN5HTrPuAPslDMApo8b7S6Of1mxL0GpkCYj3wW5uC2WQlL5I5SjI3hd57zFJPmCiRNMNbkNZQFx7o6C1xaLug== X-YMail-OSG: BWAd08gVM1lYrdw0Mx42VDoALO6Sgq_5kUB965LnDe5p6VjAKWaacZX6riyjhOM XhTUK1Ra.sWHJ7K4IgaTZjrIFp26Bt9028Q.RHHyNEOJWy4tyvSZO.SU59QQq4KyZr95wWRoZjuZ zQVRQxVVzk7iflMkSbkCbrjqDszqBthQQC8Lh6f9vuGe3Fp7nZDOIPP2A.Y0YvQzr6caY.k5nlRg jDycHD_lxGQRoGa.FtDp7MT_jZ6yAzXYcFD1e0wYbUvUc.BGEM0cGciWun730lU5SdeTJnv24arB khYEKH4MeZFW32AReSZ65qbpExmYdIFpU1GhbqBN5EfbByfqKWskeeGM5fXgTFJ.1y1PvnRZa2Gw XLoaFJ5IkXKMPBGGQSvn5XkX3mPaDZ2_YcEl1SbbBoVnL.r22X7JzJyzTu9TkjoQenon1ewd8CGX REXyHYMflnp9TnF0iITxb3NJPQ87ks1oh_YE.mTGQapbXZAHnJQk9Mnh47dqbhjjrFa8s7wOotfq iii_cu.QRam2gfr.ChfVC1sCsvRN2fw5giVL2sbwJmVgv7tHB_u1dh1eCHXd7Xaark_hQ2sPfnXB WsO8X3lpTm0RpreTHex.VFNoGJCJXOZTUh7lxqgRb.Dt9hh51zASvrq4NhO0lPu1s9HjdomZTmhF hxVOCsR4FGwtBHjwBMZ6rVd1T9I.B1awds0kNicsjHm5HA.QCmahgP28iC2Si.xLsiDdUaAmu46d yAFIK8OQa92nxi.vtQrrO__0QtATugCeWGo3cC7BKB0gQg7MCD76n5fI3aLmmnBJ4MfDoZmrpKwa l_8OnssQnwVJNNtpxR7dKoG_CMeVYNshhcycvrtMs2wzq46483uJLmtO0ngtpr7K3Zmyd3XY5yCy O54yeCcMuBetP_s6m_UdQMy4oJ1FFBlp_oTBLZ71WyDClfF.n1wjwzOdgOacF.bGiBof8Z_P2QSi vaL3LbCQz0dc3uvbXuRKVspCJDdYVL4QJJrH_gM7SnSZcHA-- Received: from sonic.gate.mail.ne1.yahoo.com by sonic301.consmr.mail.bf2.yahoo.com with HTTP; Mon, 12 Nov 2018 23:00:27 +0000 Date: Mon, 12 Nov 2018 23:00:21 +0000 (UTC) From: Markus Vester To: rsgb_lf_group@blacksheep.org Message-ID: <495235329.1250125.1542063621923@mail.yahoo.com> MIME-Version: 1.0 References: <495235329.1250125.1542063621923.ref@mail.yahoo.com> X-Mailer: WebService/1.1.12732 aolwebmail Mozilla/5.0 (Windows NT 10.0; WOW64; Trident/7.0; Touch; rv:11.0) like Gecko X-Spam-Score: 1.6 (+) 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 @@CONTACT_ADDRESS@@ for details. Content preview: Assuming a linear receiver with no AGC action, the major mechanism for desense is usually the interaction of a strong inband signal with a (software) noiseblanker. On one hand it can raise the NB trigger threshold such that the more spherics come through. More importantly, the NB chops up the strong signal itself, so it encompasses itself with noise-like AM sidebands which brighten up the spectrogram around it. [...] Content analysis details: (1.6 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [74.6.129.43 listed in list.dnswl.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail provider (markusvester[at]aol.com) 0.0 HTML_MESSAGE BODY: HTML included in message 0.0 T_DKIM_INVALID DKIM-Signature header exists but is not valid 1.6 FORGED_MUA_MOZILLA Forged mail pretending to be from Mozilla X-Scan-Signature: 18c242620d7d7b91a1caf5740aa3e326 Subject: Re: LF: Re: LF EbNaut tonite - interference rejection in SpecLab Content-Type: multipart/alternative; boundary="----=_Part_1250124_1590886622.1542063621921" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: *** X-Spam-Status: No, hits=3.2 required=5.0 tests=FORGED_MUA_MOZILLA,HTML_20_30, 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 ------=_Part_1250124_1590886622.1542063621921 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Assuming=C2=A0a linear receiver with no AGC action,=C2=A0the major mechanis= m=C2=A0for desense is usually the interaction of a strong inband=C2=A0signa= l with=C2=A0a (software) noiseblanker. On one hand=C2=A0it can raise the NB= trigger threshold such that the more spherics=C2=A0come through. More impo= rtantly, the NB chops up the strong signal itself, so it=C2=A0encompasses= =C2=A0itself with noise-like AM sidebands which brighten up the spectrogram= around it. Fortunately SpecLab has some clever FFT-filter options to deal with a stron= g narrowband interferer.=C2=A0For example,=C2=A0you can select "custom filt= er" and=C2=A0graphically draw a notch around a known=C2=A0interferer freque= ncy.=C2=A0Then there's a versatile autonotch function, albeit when setting= =C2=A0this=C2=A0up you will have to beware not to "throw out the baby with = the bathwater". Furthermore=C2=A0there's a very useful frequency selective = limiter, which automatically=C2=A0lowers the gain=C2=A0only for bins=C2=A0w= hich contain=C2=A0a=C2=A0signal above a certain threshold (reminiscent of= =C2=A0"LEILA" on Oscar satellite treansponders).=C2=A0Although this is not = complertely artifact-free, the remaining contamination is usually limited t= o very few Hz around the=C2=A0offender,=C2=A0and the rest of the spectrum b= ecomes interference-free. This "Leila" is also inserted at DL0AO=C2=A0befor= e the narrowband instances and decoders, and the effect is sometimes=C2=A0v= isible when one of us is transmitting.=C2=A0 The FFT filter options are well documented in SpecLab's help files. Note th= at for the desired effect, the noiseblanker must be inserted only after the= FFT filter, using the second=C2=A0"blackbox" (L4-L5).=C2=A0 Another=C2=A0source of interference=C2=A0are keying sidebands from the tran= smitter itself, which unfortunately cannot be mitigated on the receive side= .=C2=A0In that respect, phase-continuous modes like WSPR or MSK are relativ= ely benign. On the other hand, hard-keyed modes like EbNaut, Opera (and par= ticularly endless aural-speed Morse beacons) can be quite=C2=A0obnoxious=C2= =A0in the neighbourhood of a strong transmitter. Best regards, Markus (DF6NM) -----Urspr=C3=BCngliche Mitteilung----- Von: N1BUG An: rsgb_lf_group Verschickt: Mo, 12. Nov. 2018 22:04 Betreff: Re: LF: Re: LF EbNaut tonite Hi Stefan, OK but keep it in mind for the future. I understand we have only 2.1 kHz to play in and we have to share the resource. The DL0AO decodes were 0544 and 0550z so I think you were not transmitting at the time. 73, Paul On 11/12/18 3:36 PM, DK7FC wrote: > Hi Paul, >=20 > No problem, don't worry about the QRM. It is normal that we interfere=20 > each other sometimes. I'm sure i also reduced your WSPR SNR at DL0AO if= =20 > you were so close to me ;-) > Tonite i'll stay at 137.620 kHz. >=20 > 73, Stefan >=20 > Am 12.11.2018 21:23, schrieb N1BUG: >> Stefan, Markus, >> >> If you want to stay on 137.465 let me know... I can shut my >> transmitter off for the night. Sorry I didn't think to do that last >> night. I thought I was far enough away (in kilometers) from anyone >> with interest in EbNaut... >> >> Paul N1BUG ------=_Part_1250124_1590886622.1542063621921 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable
Assuming a linear receiver with no AGC action, the major mechani= sm for desense is usually the interaction of a strong inband sign= al with a (software) noiseblanker. On one hand it can raise the N= B trigger threshold such that the more spherics come through. More imp= ortantly, the NB chops up the strong signal itself, so it encompasses&= nbsp;itself with noise-like AM sidebands which brighten up the spectrogram = around it.

Fortunately SpecLab has som= e clever FFT-filter options to deal with a strong narrowband interferer.&nb= sp;For example, you can select "custom filter" and graphically dr= aw a notch around a known interferer frequency. Then there's a ve= rsatile autonotch function, albeit when setting this up you will = have to beware not to "throw out the baby with the bathwater". Furthermore&= nbsp;there's a very useful frequency selective limiter, which automatically=  lowers the gain only for bins which contain a sig= nal above a certain threshold (reminiscent of "LEILA" on Oscar satelli= te treansponders). Although this is not complertely artifact-free, the= remaining contamination is usually limited to very few Hz around the = offender, and the rest of the spectrum becomes interference-free. This= "Leila" is also inserted at DL0AO before the narrowband instances and= decoders, and the effect is sometimes visible when one of us is trans= mitting. 

The FFT filter options are well documented in SpecLab= 's help files. Note that for the desired effect, the noiseblanker must be i= nserted only after the FFT filter, using the second "blackbox" (L4-L5)= . 

Another source of interference are = keying sidebands from the transmitter itself, which unfortunately cannot be= mitigated on the receive side. In that respect, phase-continuous mode= s like WSPR or MSK are relatively benign. On the other hand, hard-keyed mod= es like EbNaut, Opera (and particularly endless aural-speed Morse beacons) = can be quite obnoxious in the neighbourhood of a strong transmitt= er.

Best regards,
Markus (DF6NM)

-----Urspr=C3=BCngliche Mitteilung-----
Von: N1BUG &= lt;paul@n1bug.com>
An: rsgb_lf_group <rsgb_lf_group= @blacksheep.org>
Verschickt: Mo, 12. Nov. 2018 22:04Betreff: Re: LF: Re: LF EbNaut tonite
Hi Stefan,

OK but keep it in mind for the future. I understand we have only 2.1kHz to play in and we have to share the resource. The DL0A= O decodes
were 0544 and 0550z so I think you were not tra= nsmitting at the time.

73,
Paul


On 11/12/= 18 3:36 PM, DK7FC wrote:
> Hi Paul,
= >
> No problem, don't worry about the QRM. It is n= ormal that we interfere
> each other sometimes. I'm s= ure i also reduced your WSPR SNR at DL0AO if
> you we= re so close to me ;-)
> Tonite i'll stay at 137.620 kH= z.
>
> 73, Stefan
>
> Am 12.11.2018 21:23, schrieb N1BUG:
>> Stefan, Markus,
>>
>> If you want to stay on 137.465 let me know... I can shut my=
>> transmitter off for the night. Sorry I didn't t= hink to do that last
>> night. I thought I was far = enough away (in kilometers) from anyone
>> with int= erest in EbNaut...
>>
>> Pa= ul N1BUG

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