Return-Path: Received: from rly-dd01.mx.aol.com (rly-dd01.mail.aol.com [172.19.141.148]) by air-dd06.mail.aol.com (v121_r4.4) with ESMTP id MAILINDD061-b5a4959bc4a1dc; Tue, 30 Dec 2008 01:14:57 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-dd01.mx.aol.com (v121_r4.4) with ESMTP id MAILRELAYINDD014-b5a4959bc4a1dc; Tue, 30 Dec 2008 01:14:36 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1LHXrS-0007XP-Ml for rs_out_1@blacksheep.org; Tue, 30 Dec 2008 06:13:50 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1LHXrS-0007XG-5b for rsgb_lf_group@blacksheep.org; Tue, 30 Dec 2008 06:13:50 +0000 Received: from blu0-omc1-s7.blu0.hotmail.com ([65.55.116.18]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1LHXrP-0002o0-Lr for rsgb_lf_group@blacksheep.org; Tue, 30 Dec 2008 06:13:50 +0000 Received: from BLU146-W18 ([65.55.116.8]) by blu0-omc1-s7.blu0.hotmail.com with Microsoft SMTPSVC(6.0.3790.3959); Mon, 29 Dec 2008 22:13:36 -0800 Message-ID: X-Originating-IP: [138.32.244.2] From: Laurence BY3A-KL1X China To: Date: Mon, 29 Dec 2008 21:13:35 -0900 Importance: Normal In-Reply-To: <20081230001119.6500@gmx.net> References: <005a01c968ff$2a99ee10$6401a8c0@asus> <20081230001119.6500@gmx.net> MIME-Version: 1.0 X-OriginalArrivalTime: 30 Dec 2008 06:13:36.0032 (UTC) FILETIME=[BFD2CA00:01C96A45] X-Karma: 0: X-Spam-Score: 0.9 (/) X-Spam-Report: autolearn=disabled,HTML_10_20=0.945,HTML_MESSAGE=0.001 Content-Type: multipart/alternative; boundary="_79ea1726-0b2b-4651-b046-9a826abaa858_" Subject: RE: LF: 500KHz QSB X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=FORGED_HOTMAIL_RCVD, 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 X-AOL-IP: 193.82.116.20 X-Mailer: Unknown (No Version) --_79ea1726-0b2b-4651-b046-9a826abaa858_ Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable This was a very good write up - thanks - =20 With the advent on "spectrum analyers" and panaraomic displays with the new=20= SDR radios they provide a very telling visual fade pattern on even narrow FS= K modes on HF - as you said you could actually visualize the antiphase movin= g up and down in freq and having the affect on each tone. =20 I dont know but 500 seems to have some of the worse fade characteristics, no= t too slow and not too fast - just plain difficult for the info rate for som= e modes (:-) Funny but I never remembered the fading as much when I was at s= ea on CW/MCW... =20 As Alan has pointed out the phase/antiphase cancellation on multiple iono pa= ths can ruin hours worth of listening on 137kHz and relatively small changes= in location (a few Kms) can show diverse signal reception levels on some ni= ghts. =20 Long haul pretty good at the moment - DCF39 some 45-50dBs above my neons and= other restaurant Christmas tree flashers on peak - the normal about 15-20 m= in fade pattern. =20 Laurence BY3A-KL1X Tanggu OM89UA ps Scott VE7TIL made it here on 40m WSPR last night :-) on the probe =20 > Date: Tue, 30 Dec 2008 01:11:19 +0100> From: Dennis.Hennig@gmx.de> To: rsg= b_lf_group@blacksheep.org> Subject: Re: LF: 500KHz QSB> > > Hi Gary!> > Yes=20= fading seems to be very selective. > > Have you ever been listening to a dis= tant AM radio station? Give it a try :)> There it is often audible, that a "= fading notch" travels through one sideband down to lower modulation frequenc= ies, then there is a moment of often terribly distorted audio due to the not= ched out carrier (the remaining sidebands "virtually much overmodulated"), t= hen the "notch" goes further through the second sideband (if this also passe= s your filter).> > The fading is fast on shortwave, where almost all the tim= e different skywaves "are fighting each other" , medium fast on medium wave,= and in the case of longwave transmitters sometimes very slow (may take minu= tes). > > Here in Berlin this longwave radio QSB appears very nicely at dusk= to the 204km away "Polskie Radio I" 225kHz transmitter. The skywave becomes= stronger and seems to equal the value of the groundwave, so constructive an= d destructive interference takes place.> > Have a nice evening :)> Dennis >=20= DL6NVC> > > -- > Psssst! Schon vom neuen GMX MultiMessenger geh=F6rt? Der ka= nn`s mit allen: http://www.gmx.net/de/go/multimessenger>=20 _________________________________________________________________ Life on your PC is safer, easier, and more enjoyable with Windows Vista=AE.=20 http://clk.atdmt.com/MRT/go/127032870/direct/01/=3D --_79ea1726-0b2b-4651-b046-9a826abaa858_ Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable This was a very good write up - thanks -
 
With the advent on "spectrum analyers" and panaraomic displays with the new=20= SDR radios they provide a very telling visual fade pattern on even narrow FS= K modes on HF - as you said you could actually visualize the antiphase movin= g up and down in freq and having the affect on each tone.
 
I dont know but 500 seems to have some of the worse fade characteristics, no= t too slow and not too fast - just plain difficult for the info rate for som= e modes (:-) Funny but I never remembered the fading as much when I was at s= ea on CW/MCW...
 
As Alan has pointed out the phase/antiphase cancellation on multiple iono pa= ths can ruin hours worth of listening on 137kHz and relatively small changes= in location (a few Kms) can show diverse signal reception levels on some ni= ghts.
 
Long haul pretty good at the moment - DCF39 some 45-50dBs above my neons and= other restaurant Christmas tree flashers on peak - the normal about 15-20 m= in fade pattern.
 
Laurence BY3A-KL1X Tanggu OM89UA
ps  Scott VE7TIL made it here on 40m WSPR last night :-) on the probe  


> Date: Tue, 30 Dec 2008 01:11:19 +0100
> From: Dennis.Henn= ig@gmx.de
> To: rsgb_lf_group@blacksheep.org
> Subject: Re: LF:=20= 500KHz QSB
>
>
> Hi Gary!
>
> Yes fading se= ems to be very selective.
>
> Have you ever been listening to=20= a distant AM radio station? Give it a try :)
> There it is often audib= le, that a "fading notch" travels through one sideband down to lower modulat= ion frequencies, then there is a moment of often terribly distorted audio du= e to the notched out carrier (the remaining sidebands "virtually much overmo= dulated"), then the "notch" goes further through the second sideband (if thi= s also passes your filter).
>
> The fading is fast on shortwave= , where almost all the time different skywaves "are fighting each other" , m= edium fast on medium wave, and in the case of longwave transmitters sometime= s very slow (may take minutes).
>
> Here in Berlin this longwa= ve radio QSB appears very nicely at dusk to the 204km away "Polskie Radio I"= 225kHz transmitter. The skywave becomes stronger and seems to equal the val= ue of the groundwave, so constructive and destructive interference takes pla= ce.
>
> Have a nice evening :)
> Dennis
> DL6NVC>
>
> --
> Psssst! Schon vom neuen GMX MultiMessen= ger geh=F6rt? Der kann`s mit allen: http://www.gmx.net/de/go/multimessenger<= BR>>


Life on your PC is safer, easier, and more enjoy= able with Windows Vista=AE. See how =3D --_79ea1726-0b2b-4651-b046-9a826abaa858_--