Return-Path: X-Spam-DCC: paranoid 1102; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=0.6 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_AOL_TAGS,HTML_10_20,HTML_MESSAGE,UNPARSEABLE_RELAY autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id t61FS3Lg014399 for ; Wed, 1 Jul 2015 17:28:03 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1ZAJsJ-0002Yt-R0 for rs_out_1@blacksheep.org; Wed, 01 Jul 2015 16:24:35 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1ZAJsJ-0002Yk-8g for rsgb_lf_group@blacksheep.org; Wed, 01 Jul 2015 16:24:35 +0100 Received: from omr-m5.mx.aol.com ([64.12.232.237]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.85) (envelope-from ) id 1ZAJsG-0004kJ-CS for rsgb_lf_group@blacksheep.org; Wed, 01 Jul 2015 16:24:34 +0100 Received: from mtaomg-mbe02.mx.aol.com (mtaomg-mbe02.mx.aol.com [172.26.254.176]) by omr-m5.mx.aol.com (Outbound Mail Relay) with ESMTP id AA74E380001AC for ; Wed, 1 Jul 2015 11:24:29 -0400 (EDT) Received: from core-afa09c.mail.aol.com (core-afa09.mail.aol.com [172.27.24.9]) by mtaomg-mbe02.mx.aol.com (OMAG/Core Interface) with ESMTP id 6FA2038000082 for ; Wed, 1 Jul 2015 11:24:29 -0400 (EDT) References: <5593D766.3030705@posteo.de> To: rsgb_lf_group@blacksheep.org In-Reply-To: <5593D766.3030705@posteo.de> X-MB-Message-Source: WebUI MIME-Version: 1.0 From: Markus Vester X-MB-Message-Type: User X-Mailer: AOL Webmail BASIC Received: from 192.35.17.12 by webmail-va039.sysops.aol.com (149.174.102.69) with HTTP (WebMailUI); Wed, 01 Jul 2015 11:24:28 -0400 Message-Id: <8D2822927E61567-D74-1455B0@webmail-va039.sysops.aol.com> X-Originating-IP: [192.35.17.12] Date: Wed, 1 Jul 2015 11:24:29 -0400 x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20150623; t=1435764269; bh=3/iOoyqyloEsm4Wr0H7b1fifP1MyKeOmkffpaFnaT2M=; h=From:To:Subject:Message-Id:Date:MIME-Version:Content-Type; b=rTWCyCy9sDDjhVHu6LAG7oikqEE1GqWQRCxrQuY4t7hCsrxwGdK7AKsYWNsn+A6e6 SN0T9ZX4J4of8oHtW9TRORvjqPn7fDUQXOxA4DeNFrQSB6g59jOhWVoKT+cosOz+be hdCSUQR/QFGdx+asRPcJ77uPcO/1pK8IMb8blwIY= x-aol-sid: 3039ac1afeb05594062d7a2c X-Scan-Signature: 052e5a7ab87161a07560b72babff3441 Subject: Re: LF: SpecLab's frequence selective limiter: Better performance for your WSPR decoder! Content-Type: multipart/alternative; boundary="--------MB_8D2822927F9205F_D74_24F4F7_webmail-va039.sysops.aol.com" 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-Scanned-By: MIMEDefang 2.56 on 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 3588 This is a multi-part message in MIME format. ----------MB_8D2822927F9205F_D74_24F4F7_webmail-va039.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" =20Hi=20Wolf,=20Stefan,=0D=0A=C2=A0=0D=0A>=20Maybe=20the=20'window=20function= '=20of=20the=20noiseblanker=20itself=20can=20be=20improved=20=0D=0A=C2=A0=0D=0AI= n=20the=20presence=20of=20strong=20in-band=20signals,=20there's=20probably=20a=20= fundamental=20tradeoff=20regarding=20the=20choice=20of=20noiseblanker=20ramp=20t= iming:=20We=20want=20fast=20ramps=20to=20achieve=20effective=20blanking=20with=20= little=20signal=20loss,=20but=20slow=20ramps=20to=20have=20narrow=20spectral=20s= kirts=20around=20a=20strong=20chopped-up=20carrier.=20If=20the=20desired=20signa= l=20is=20only=20a=20few=20Hz=20away=20both=20can't=20be=20had=20at=20the=20same=20= time,=20no=20matter=20how=20nicely=20shaped=20the=20ramps=20would=20be.=0D=0A=C2= =A0=0D=0AOne=20approach=20would=20be=20to=20do=20a=20FFT=20first,=20and=20route=20= channels=20inhabited=20by=20strong=20signals=20around=20the=20noiseblanker.=20If= =20I=20recall=20right=20this=20strategy=20has=20been=20implemented=20by=20SM5BSZ= =20in=20the=20Linrad=20noise=20blanker=20(which=20I=20haven't=20tried=20yet).=20= Up=20to=20now,=20my=20usual=20workaround=20has=20been=20to=20manually=20draw=20a= =20-25=20dB=20FFT=20notch=20around=20strong=20signals,=20but=20this=20is=20obvio= usly=20not=20very=20flexible.=20The=20SpecLab=20selective=20limiter=20solves=20t= he=20problem=20because=20it=20automatically=20reduces=20strong=20carriers=20alre= ady=20in=20the=20linear=20domain,=20before=20they=20get=20widened=20up=20by=20th= e=20noiseblanker=20modulation.=0D=0A=C2=A0=0D=0ABest=2073,=20=0D=0AMarkus=20(DF6= NM)=0D=0A=0D=0A=0D=0A=0D=0A=0D=0A-----Urspr=C3=BCngliche=20Mitteilung-----=20=0D= =0AVon:=20DK7FC=20<selberdenken@posteo.de>=0D=0AAn:=20rsgb_lf_group=20<= rsgb_lf_group@blacksheep.org>=0D=0AVerschickt:=20Mi,=201=20Jul=202015=202:06=20= pm=0D=0ABetreff:=20Re:=20LF:=20SpecLab's=20frequence=20selective=20limiter:=20Be= tter=20performance=20for=20your=20WSPR=20decoder!=0D=0A=0D=0A=20=20=20=20=20=20=20= =20=20=20Hi=20Wolf,=0D=0A=20=0D=0A=20Am=2001.07.2015=2011:13,=20schrieb=20wolf_d= l4yhf:=20=20=20=20=20=20=20Hi=20Stefan,=0D=0A=20=20=20=0D=0A=20Thanks=20for=20th= e=20interesting=20test.=20I=20seem=20to=20have=20little=20luck=20with=20the=20dr= opbox=20links=20(they=20almost=20always=20result=20in=20some=20sort=20of=20file-= not-found=20error)=20but=20I=20can=20imagine=20the=20combination.=20Maybe=20ther= e's=20another=20link=20to=20your=20dropbox=20storage,=20or=20maybe=20the=20space= =20characters=20in=20the=20filename=20make=20it=20unaccessable=20?=0D=0A=20=20=20= =0D=0A=20=20Hm,=20here=20the=20link=20works=20when=20clicking=20on=20it=20into=20= the=20mail.=20I'm=20using=20the=20thunderbird=20browser..=0D=0A=20=20=20=20=20=0D= =0A=20I'm=20curious=20about=20what=20actually=20causes=20the=20spectral=20spread= ing=20of=20the=20strong=20carrier=20(caused=20by=20the=20normal=20noiseblanker),= =20and=20why=20the=20frequency-selective=20limiter=20can=20achieve=20a=20steeper= =20roll-off=20(over=20frequency)=20than=20the=20carefully=20shaped=20noiseblanke= r=20response.=20Maybe=20the=20'window=20function'=20of=20the=20noiseblanker=20it= self=20can=20be=20improved=20(by=20something=20more=20elaborate=20than=20the=20r= aised-cosine-shaped=20edges,=20and=20the=20flat=20'window=20ledge'=20in=20betwee= n)=20?=20=0D=0A=20=20=20=0D=0A=20=20Ehm,=20yes.=20If=20you=20think=20so,=20then=20= it=20must=20be=20possible!=20:-)=0D=0A=20=0D=0A=2073,=20Stefan=20(sitting=20in=20= a=20air-conditioned=20office=20;-)=20)=0D=0A=20=0D=0A=20=0D=0A=20=0D=0A=20=0D=0A= =20=20=20=20=20=0D=0A=20All=20the=20best,=0D=0A=20=C2=A0Wolf=20DL4YHF=0D=0A=20=C2= =A0=20(QRN=20season=20and=20extraordinary=20temperatures=20up=20to=2040=20=C2=B0= C=20on=20their=20way=20...=20yucc...)=0D=0A=20=20=20=0D=0A=20=20=20=0D=0A=20Am=20= 01.07.2015=2001:36,=20schrieb=20DK7FC:=0D=0A=20=20=20=0D=0A=20=20=20=20=20=20=20= =20=20Hi=20all,=20=0D=0A=20=20=20=20=20=0D=0A=20My=20MF=20RX-experiments=20are=20= continuing=20and=20i=20discovered=20SpecLab's=20frequency=20selective=20limiter:= =20=0D=0A=20=20=20=20=20=0D=0A=20Today=20it=20is=20a=20quite=20noisy=20night.=0D= =0A=20=20=20=20=20=0D=0A=20As=20reported=20previously=20i'm=20running=20two=20Sp= ecLab=20instances=20from=20the=20same=20signal=20source=20(VAC1)=20feeding=20two= =20WSPR=20instances,=20so=20i=20can=20directly=20see=20the=20effect=20of=20the=20= NB=20or=20other=20techniques.=0D=0A=20This=20image=20shows=20the=20experiment:=20= https://dl.dropboxusercontent.com/u/19882028/MF/Frequence%20selective%20limiter.= png=0D=0A=20The=20upper=20WSPR+SpecLab=20instance=20is=20using=20the=20NB,=20the= =20lower=20one=20just=20makes=20the=20necessary=20frequency=20conversion=20and=20= SSB=20filter=20setting=20(474.2=20kHz=20"dial").=0D=0A=20=20=20=20=20=0D=0A=20Us= ing=20SpecLab's=20noise=20blanker=20(NB)=20makes=20an=20improvement=20of=203...7= =20dB=20tonite,=20as=20reported=20by=20WSPR-2,=20so=20it=20is=20worth=20to=20run= =20it!=20Actually=20there=20were=20many=20decodes=20by=20that=20instance=20which= =20is=20using=20the=20NB=20that=20didn't=20decode=20on=20the=20other=20one,=20fo= r=20example=20G3WCB=20at=2022:32=20UTC=20(see=20text=20fields).=20Without=20the=20= NB=20there=20was=20no=20trace=20at=20all!=0D=0A=20=20=20=20=20=0D=0A=20However,=20= when=20running=20the=20NB,=20strong=20signals=20will=20cause=20the=20NB=20the=20= rise=20the=20noise=20in=20the=20spectrum.=20DK2DB=20is=20a=20strong=20signal=20h= ere,=20showing=2040=20dB=20above=20the=20noise=20(in=201=20Hz),=20(yes=20i'm=20s= uch=20a=20strong=20signal=20too,=20i=20know!!!).=20You=20can=20see=20the=20effec= t=20on=20the=20upper=20spectrogram=20at=2021:50=20or=2022:00=20UTC.=20A=20small=20= signal=20like=20G3WCB=20would=20be=20lost=20in=20that=20background=20noise=20whi= ch=20is=20caused=20by=20the=20NB.=20However=20without=20the=20NB=20it=20wouldn't= =20decode=20as=20well!=20=0D=0A=20=20=20=20=20=0D=0A=20So=20what=20is=20the=20so= lution?=20Maybe=20something=20like=20an=20auto=20notch=20filter=20but=20if=20thi= s=20is=20very=20sharp,=20it=20also=20causes=20a=20higher=20noise=20arround.=20Ac= tually=20it=20must=20be=20something=20which=20just=20lowers=20the=20strong=20sig= nals=20a=20bit,=20maybe=2025=20dB=20but=20leaves=20the=20rest=20as=20it=20is.=20= In=20a=20phone=20call=20with=20Markus=20we=20discussed=20about=20this=20and=20di= scovered=20the=20the=20frequence=20selective=20limiter=20and=20it's=20performanc= e.=20It=20can=20be=20found=20in=20the=20options=20register=20card=20of=20the=20f= ilter=20control=20window=20and=20must=20be=20enabled=20there.=20I've=20the=20con= figured=20a=20band=20pass=20filter=20including=20this=20limiter.=20After=20that=20= filter=20and=20limiter,=20the=20NB=20is=20running=20in=20the=20blackbox=20betwee= n=20L4=20and=20L5.=0D=0A=20=20=20=20=20=0D=0A=20Now,=20when=20enabling=20the=20f= ilter=20and=20defining=20a=20limit=20just=20about=2010=20dB=20above=20the=20aver= age=20noise=20floor,=20the=20signal=20of=20DK2DB=20is=20reduced=20to=20a=20level= =20which=20does=20not=20cause=20the=20NB=20to=20rise=20the=20noise=20floor!=20Yo= u=20can=20see=20it=20at=2022:08=20UTC.=20In=20the=20list=20you=20can=20see=20tha= t=20the=20displayed=20SNR=20dropped=20from=20+3=20to=20-15=20dB=20at=2022:16=20U= TC=20where=20is=20reduced=20the=20limiter=20threshold=20a=20bit=20more.=20So=20d= ecodes=20of=20the=20strong=20local=20stations=20do=20still=20happen=20while=20th= e=20NB=20is=20not=20acting=20on=20the=20strong=20signal,=20and=20QRN=20is=20sign= ificantly=20blanked,=20allowing=20to=20decode=20weak=20signals!=20For=20example,= =20see=20G3XIZ=20at=2022:44=20UTC,=20showing=20-17=20dB=20instead=20of=20-25=20d= B,=20i.e.=20an=20improvement=20of=208=20dB!=20DK2DB=20has=20been=20active=20to=20= that=20time.=0D=0A=20=20=20=20=20=0D=0A=2073,=20Stefan=0D=0A=20=20=20=20=20=0D=0A= =20=20=20=20=20=20=0D=0A=20=20=0D=0A=20=20=20=0D=0A=20=0A=0A ----------MB_8D2822927F9205F_D74_24F4F7_webmail-va039.sysops.aol.com Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset="utf-8" =0D=0A=0D=0A=0D=0A
=20Hi=20= Wolf,=20Stefan,
=0D=0A=0D=0A
 
=0D=0A=0D=0A
>=20Maybe=20= the=20'window=20function'=20of=20the=20noiseblanker=20itself=20can=20be=20improv= ed=20
=0D=0A=0D=0A
 
=0D=0A=0D=0A
In=20the=20presence=20o= f=20strong=20in-band=20signals,=20there's=20probably=20a=20fundamental=20tradeof= f=20regarding=20the=20choice=20of=20noiseblanker=20ramp=20timing:=20We=20want=20= fast=20ramps=20to=20achieve=20effective=20blanking=20with=20little=20signal=20lo= ss,=20but=20slow=20ramps=20to=20have=20narrow=20spectral=20skirts=20around=20a=20= strong=20chopped-up=20carrier.=20If=20the=20desired=20signal=20is=20only=20a=20f= ew=20Hz=20away=20both=20can't=20be=20had=20at=20the=20same=20time,=20no=20matter= =20how=20nicely=20shaped=20the=20ramps=20would=20be.
=0D=0A=0D=0A
 = ;
=0D=0A=0D=0A
One=20approach=20would=20be=20to=20do=20a=20FFT=20first,= =20and=20route=20channels=20inhabited=20by=20strong=20signals=20around=20the=20n= oiseblanker.=20If=20I=20recall=20right=20this=20strategy=20has=20been=20implemen= ted=20by=20SM5BSZ=20in=20the=20Linrad=20noise=20blanker=20(which=20I=20haven't=20= tried=20yet).=20Up=20to=20now,=20my=20usual=20workaround=20has=20been=20to=20man= ually=20draw=20a=20-25=20dB=20FFT=20notch=20around=20strong=20signals,=20but=20t= his=20is=20obviously=20not=20very=20flexible.=20The=20SpecLab=20selective=20limi= ter=20solves=20the=20problem=20because=20it=20automatically=20reduces=20strong=20= carriers=20already=20in=20the=20linear=20domain,=20before=20they=20get=20widened= =20up=20by=20the=20noiseblanker=20modulation.
=0D=0A=0D=0A
 
= =0D=0A=0D=0A
Best=2073,=20
=0D=0AMarkus=20(DF6NM)
=0D=0A
=0D=0A=0D=0A=0D=0A

=0D=0A
=0D=0A-----Urspr=C3=BCngliche=20Mitteilung---= --=20
=0D=0AVon:=20DK7FC=20<selberdenken@posteo.de>
=0D=0AAn:=20rsgb= _lf_group=20<rsgb_lf_group@blacksheep.org>
=0D=0AVerschickt:=20Mi,=201=20= Jul=202015=202:06=20pm
=0D=0ABetreff:=20Re:=20LF:=20SpecLab's=20frequence=20s= elective=20limiter:=20Better=20performance=20for=20your=20WSPR=20decoder!
=0D= =0A
=0D=0A=20=0D=0A=20=20=20=20=20=20=20=20=0D=0A=20Hi=20Wolf,
=0D=0A=20
=0D=0A=20Am=2001.07.= 2015=2011:13,=20schrieb=20wolf_dl4yhf:=20=20=20=20=20= =20=20=0D=0AHi=20Stefan,
=0D=0A=20=20= =20
=0D=0A=20Thanks=20for=20the=20interesting=20test.=20I=20seem=20to=20have=20= little=20luck=20with=20the=20dropbox=20links=20(they=20almost=20always=20result=20= in=20some=20sort=20of=20file-not-found=20error)=20but=20I=20can=20imagine=20the=20= combination.=20Maybe=20there's=20another=20link=20to=20your=20dropbox=20storage,= =20or=20maybe=20the=20space=20characters=20in=20the=20filename=20make=20it=20una= ccessable=20?
=0D=0A=20=20=20
=0D=0A=20=20Hm,=20here=20the=20= link=20works=20when=20clicking=20on=20it=20into=20the=20mail.=20I'm=20using=20th= e=20thunderbird=20browser..
=0D=0A=20=20=20=20=0D= =0A=20
=0D=0A=20I'm=20curious=20abou= t=20what=20actually=20causes=20the=20spectral=20spreading=20of=20the=20strong=20= carrier=20(caused=20by=20the=20normal=20noiseblanker),=20and=20why=20the=20frequ= ency-selective=20limiter=20can=20achieve=20a=20steeper=20roll-off=20(over=20freq= uency)=20than=20the=20carefully=20shaped=20noiseblanker=20response.=20Maybe=20th= e=20'window=20function'=20of=20the=20noiseblanker=20itself=20can=20be=20improved= =20(by=20something=20more=20elaborate=20than=20the=20raised-cosine-shaped=20edge= s,=20and=20the=20flat=20'window=20ledge'=20in=20between)=20?=20
=0D=0A=20=20=20= =0D=0A=20=20Ehm,=20yes.=20If=20you=20think=20so,=20then=20it=20= must=20be=20possible!=20:-)
=0D=0A=20
=0D=0A=2073,=20Stefan=20(sitting=20i= n=20a=20air-conditioned=20office=20;-)=20)
=0D=0A=20
=0D=0A=20
=0D=0A=20=
=0D=0A=20
=0D=0A=20=20=20=20=0D=0A=20
=0D=0A=20All=20the=20best,
=0D=0A=20&nbs= p;Wolf=20DL4YHF
=0D=0A=20 =20(QRN=20season=20and=20extraordinary=20tempe= ratures=20up=20to=2040=20=C2=B0C=20on=20their=20way=20...=20yucc...)
=0D=0A=20= =20=20
=0D=0A=20=20=20
=0D=0A=20Am=2001.07.2015=2001:36,=20schrieb=20DK7FC= :
=0D=0A=20=20=20=0D=0A=20=20=20=20=20=20=20= =20=20Hi=20all,=20
=0D=0A=20=20=20=20=20
=0D=0A=20My=20MF=20RX-experiments= =20are=20continuing=20and=20i=20discovered=20SpecLab's=20frequency=20selective=20= limiter:=20
=0D=0A=20=20=20=20=20
=0D=0A=20Today=20it=20is=20a=20quite=20n= oisy=20night.
=0D=0A=20=20=20=20=20
=0D=0A=20As=20reported=20previously=20= i'm=20running=20two=20SpecLab=20instances=20from=20the=20same=20signal=20source=20= (VAC1)=20feeding=20two=20WSPR=20instances,=20so=20i=20can=20directly=20see=20the= =20effect=20of=20the=20NB=20or=20other=20techniques.
=0D=0A=20This=20image=20= shows=20the=20experiment:=20https://dl.dropboxusercontent.com/u/19882028/MF/Freque= nce%20selective%20limiter.png
=0D=0A=20The=20upper=20WSPR+SpecLab=20insta= nce=20is=20using=20the=20NB,=20the=20lower=20one=20just=20makes=20the=20necessar= y=20frequency=20conversion=20and=20SSB=20filter=20setting=20(474.2=20kHz=20"dial= ").
=0D=0A=20=20=20=20=20
=0D=0A=20Using=20SpecLab's=20noise=20blanker=20(= NB)=20makes=20an=20improvement=20of=203...7=20dB=20tonite,=20as=20reported=20by=20= WSPR-2,=20so=20it=20is=20worth=20to=20run=20it!=20Actually=20there=20were=20many= =20decodes=20by=20that=20instance=20which=20is=20using=20the=20NB=20that=20didn'= t=20decode=20on=20the=20other=20one,=20for=20example=20G3WCB=20at=2022:32=20UTC=20= (see=20text=20fields).=20Without=20the=20NB=20there=20was=20no=20trace=20at=20al= l!
=0D=0A=20=20=20=20=20
=0D=0A=20However,=20when=20running=20the=20NB,=20= strong=20signals=20will=20cause=20the=20NB=20the=20rise=20the=20noise=20in=20the= =20spectrum.=20DK2DB=20is=20a=20strong=20signal=20here,=20showing=2040=20dB=20ab= ove=20the=20noise=20(in=201=20Hz),=20(yes=20i'm=20such=20a=20strong=20signal=20t= oo,=20i=20know!!!).=20You=20can=20see=20the=20effect=20on=20the=20upper=20spectr= ogram=20at=2021:50=20or=2022:00=20UTC.=20A=20small=20signal=20like=20G3WCB=20wou= ld=20be=20lost=20in=20that=20background=20noise=20which=20is=20caused=20by=20the= =20NB.=20However=20without=20the=20NB=20it=20wouldn't=20decode=20as=20well!=20=0D=0A=20=20=20=20=20
=0D=0A=20So=20what=20is=20the=20solution?=20Maybe=20s= omething=20like=20an=20auto=20notch=20filter=20but=20if=20this=20is=20very=20sha= rp,=20it=20also=20causes=20a=20higher=20noise=20arround.=20Actually=20it=20must=20= be=20something=20which=20just=20lowers=20the=20strong=20signals=20a=20bit,=20may= be=2025=20dB=20but=20leaves=20the=20rest=20as=20it=20is.=20In=20a=20phone=20call= =20with=20Markus=20we=20discussed=20about=20this=20and=20discovered=20the=20the=20= frequence=20selective=20limiter=20and=20it's=20performance.=20It=20= can=20be=20found=20in=20the=20options=20register=20card=20of=20the=20filter=20co= ntrol=20window=20and=20must=20be=20enabled=20there.=20I've=20the=20configured=20= a=20band=20pass=20filter=20including=20this=20limiter.=20After=20that=20f= ilter=20and=20limiter,=20the=20NB=20is=20running=20in=20the=20blackbox=20between= =20L4=20and=20L5.
=0D=0A=20=20=20=20=20
=0D=0A=20Now,=20when=20enabling=20= the=20filter=20and=20defining=20a=20limit=20just=20about=2010=20dB=20above=20the= =20average=20noise=20floor,=20the=20signal=20of=20DK2DB=20is=20reduced=20to=20a=20= level=20which=20does=20not=20cause=20the=20NB=20to=20rise=20the=20noise=20floor!= =20You=20can=20see=20it=20at=2022:08=20UTC.=20In=20the=20list=20you=20can=20see=20= that=20the=20displayed=20SNR=20dropped=20from=20+3=20to=20-15=20dB=20at=2022:16=20= UTC=20where=20is=20reduced=20the=20limiter=20threshold=20a=20bit=20more.=20So= =20decodes=20of=20the=20strong=20local=20stations=20do=20still=20happen=20while=20= the=20NB=20is=20not=20acting=20on=20the=20strong=20signal,=20and=20QRN=20is=20si= gnificantly=20blanked,=20allowing=20to=20decode=20weak=20signals!=20For=20ex= ample,=20see=20G3XIZ=20at=2022:44=20UTC,=20showing=20-17=20dB=20instead=20of=20-= 25=20dB,=20i.e.=20an=20improvement=20of=208=20dB!=20DK2DB=20has=20been=20active=20= to=20that=20time.
=0D=0A=20=20=20=20=20
=0D=0A=2073,=20Stefan
=0D=0A=20= =20=20=20=20
=0D=0A=20=20=20=20=20=20
=0D=0A=20=20= =0D=0A=20=20=20=0D=0A=20 ----------MB_8D2822927F9205F_D74_24F4F7_webmail-va039.sysops.aol.com--