Return-Path: Received: from rly-da03.mx.aol.com (rly-da03.mail.aol.com [172.19.129.77]) by air-da07.mail.aol.com (v121_r4.4) with ESMTP id MAILINDA072-a5b497cf43477; Sun, 25 Jan 2009 18:22:36 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-da03.mx.aol.com (v121_r4.4) with ESMTP id MAILRELAYINDA033-a5b497cf43477; Sun, 25 Jan 2009 18:22:30 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1LREIm-0000nk-P8 for rs_out_1@blacksheep.org; Sun, 25 Jan 2009 23:22:04 +0000 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1LREIm-0000nb-0M for rsgb_lf_group@blacksheep.org; Sun, 25 Jan 2009 23:22:04 +0000 Received: from smtp5.freeserve.com ([193.252.22.159]) by relay2.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1LREIg-0003HS-0D for rsgb_lf_group@blacksheep.org; Sun, 25 Jan 2009 23:22:03 +0000 Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3402.me.freeserve.com (SMTP Server) with ESMTP id 7D54A1C00085 for ; Mon, 26 Jan 2009 00:21:50 +0100 (CET) Received: from AGB (unknown [91.109.23.220]) by mwinf3402.me.freeserve.com (SMTP Server) with SMTP id 051701C00083 for ; Mon, 26 Jan 2009 00:21:49 +0100 (CET) X-ME-UUID: 20090125232150211.051701C00083@mwinf3402.me.freeserve.com Message-ID: <277ED905B5094EB6B730CEE83FEF118F@AGB> From: "Graham" To: References: <20090125092908.0aec06a4@lurcher><7EC707A6E2D94414AEBBC52C6159581C@JimPC><002001c97f0a$cf16fac0$ae01a8c0@youry0mkaz8jaq><20090125165335.47fc3399@lurcher><7690F13DCE5D44BA8A5AA126607E7979@JimPC> <20090125180430.1d63e1c7@lurcher> <6449616DC58940A19C537A59F53828DA@AGB> <00d201c97f20$bd909520$6401a8c0@asus> <00f101c97f2d$e530b440$6401a8c0@asus> In-Reply-To: Date: Sun, 25 Jan 2009 23:21:39 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8050.1202 X-MIMEOLE: Produced By Microsoft MimeOLE V14.0.8050.1202 X-Spam-Score: 0.1 (/) X-Spam-Report: autolearn=disabled,AWL=0.075 Subject: Re: LF: Re: WSPR 503.5 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=original Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.1 required=5.0 tests=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-IP: 193.82.116.20 Jim If you want a laugh ,re stability - check out the posting of the spectrum plot on 4 mtrs when I was testing with Gary .. transverters are 'not' quite as stable as you would like .. but the wspr system kept on decoding ! The 504 carrier is 20 db over the noise floor at the moment at my qth ... splatter may be a problem, but as to its effect on wspr decode I don't know , close in cw seems to do the most damage , Gary is showing on wspr -1 db Andy at -20 and yourself at -12 db at the moment , Gary is about 30 miles from my qth speclab shows Gary at 30 db over the noise floor G .. -------------------------------------------------- From: "James Moritz" Sent: Sunday, January 25, 2009 10:47 PM To: Subject: LF: Re: WSPR 503.5 > > Dear LF Group, > > M0BMU is now transmitting WSPR again - also currently logging G4JNT and > G4WGT > > Re: the question of a WSPR centre frequency, 503.9kHz +/-100Hz would seem > sensible - it should be possible to allow a guard band of say 10 or 20Hz > to > the band edge within that bandwidth. There would not be much point in > trying > to transmit a WSPR signal if your TX could not maintain that kind of > accuracy. With that range, the maximum contiguous spectrum would be > available for other things in the amateur band. The only problem would be > for locations where there is a lot of noise around 504kHz - I believe > Finbar > has this problem with harmonics of 252kHz, but I don't know how widespread > a > problem that is. If it is a problem, 501.1kHz +/-100Hz would be more > suitable... > > Re: ERP vs TX power. There seems to be an assumption for the HF users of > WSPR that you should specify the TX power. I think this is partly because > many people are unfamiliar with the concept of ERP. Some others have the > idea that you could deduce information on antenna performance by looking > at > the TX power of the transmitting stations and SNR, distances and > directions > reported by receiving stations. I don't think that is feasible; to do so > you > would also need to have fairly accuate knowledge of the directional > pattern > of the transmitting antenna, the path loss (including the effects of > ground > loss, fading, ionospheric conditions at that particular time), the > directional pattern of the receiving antenna, and the band noise level at > the receiving antenna at that particular time. These variables would be > different for every receiving station, and also vary a lot over time. As > others have said, an intelligent estimate of ERP will usually be within a > few dBs, which implies the antenna performance will be usually already be > known with much better accuracy than all these other variables. So I think > it would be a much better idea to specify ERP, and use WSPR reports as a > tool to analyse propagation, rather than try to do it the other way round. > > As Graham says, on HF the ERP will be within not-many-dBs of the TX power > anyway, unless the antenna is very big or very small. At LF/MF there are > wide variations. G4WGT running 5W is quite QRP with his home antenna, but > would probably be well over the 1W ERP limit if he were using G3KEV's > antenna. So really you have to state ERP in order to give a realistic > measure of how strong the signal is at source. > > In answer to: >>>>>Of course 2mW ERP from a small antenna won't go as far as 2mW ERP from >>>>>a >>>>>large one. > > Of course it will! ERP is a measure of how much field strength is produced > at a given distance, so if both stations have the same ERP, the signals > will > go equally far - that is the point of ERP, it is a measure of the actual > radiated signal, after losses and so forth are accounted for. If the small > antenna is producing 2mW ERP, it implies that more TX power is being used > to > get that figure than is required by the presumably more efficient big > antenna. Not many people believe it though! I actually did the experiment > back in 2000 on 136kHz, setting up a small inverted L next to the 100m > high > Decca Navigator mast at Puckeridge, and adjusting the power levels until > the > radiated signal levels were roughly similar (about 1W TX for the 100m > mast, > 350W for the inv L as I recall...). The signal reports I got indicated the > same relative levels from the two antennas, at distances between about 2km > and 1000km. > > Cheers, Jim Moritz > 73 de M0BMU > > > > > > > > > ----- Original Message ----- > From: "Gary - G4WGT" > To: > Sent: Sunday, January 25, 2009 8:45 PM > Subject: RE: LF: Re: WSPR 503.5 > > >> Graham, LF, >> >> I do agree that ERP is more meaningful & as Mal & Andy stated it is the >> criteria with which the licence is approved. >> >> My comment was to follow the WSPR recommended method as adopting ERP >> would >> mean there are two "standards". >> >> I ERP is adopted for LF then it should be international & not just UK, so >> an >> official announcement by the main WSPR group would be required. >> Comments please. >> >> Gary - G4WGT. >> >> >> >> -----Original Message----- >> From: owner-rsgb_lf_group@blacksheep.org >> [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Graham >> Sent: 25 January 2009 20:29 >> To: rsgb_lf_group@blacksheep.org >> Subject: Re: LF: Re: WSPR 503.5 >> >> Gary, >> >> I don't think a guard band is really needed as if you set the centre >> carrier >> >> frequency to 503.9 , then operating at the extreme edges is not really >> possible, you're right on the edge of the waterfall. the deviation is >> only >> round 6 hz >> >> Re power .. I would say, the erp is the most meaningful, actual power >> supplied to the antenna without the performance data of the array doesn't >> really mean too much ? >> >> G .. >> >> -------------------------------------------------- >> From: "Gary - G4WGT" >> Sent: Sunday, January 25, 2009 7:11 PM >> To: >> Subject: RE: LF: Re: WSPR 503.5 >> >>> >>> Hi All, >>> >>> In agreement with John & Graham, I believe that makes sense. The top >>> part >>> of >>> the band is probably the least used area so we just need to agree on a >>> 200Hz >>> slot of either 503.800 to 504.000KHz with no guard band or 503.700 to >>> 503.900KHz with a 100Hz guard band. >>> >>> My WSPR beacon is now active using dial frequency 502.000KHz & >>> 503.550KHz >>> data. >>> >>> Looks like Andy just beat me to the announcement. >>> >>> 73 >>> >>> Gary - G4WGT >>> >>> -----Original Message----- >>> From: owner-rsgb_lf_group@blacksheep.org >>> [mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of Graham >>> Sent: 25 January 2009 18:32 >>> To: rsgb_lf_group@blacksheep.org >>> Subject: Re: LF: Re: WSPR 503.5 >>> >>> John, >>> >>> Looks close to my post , just, as wspr is such a narrow mode, could >>> move >>> to >>> >>> the band edge without problems >>> clear of the occasional qrss slightly lower down >>> >>> With a move to vfo/exciter control, defining the wspr slot is a >>> reasonable >>> concept as it will allow other 'casual' >>> monitor stations to be established .. and negate the number of post >>> needed >>> to announce a test ! >>> >>> What of the beacons that used this area of the band , are they qrt or >>> just >>> sleeping ? >>> >>> G .. >>> >>> >>> >>> -------------------------------------------------- >>> From: "John P-G" >>> Sent: Sunday, January 25, 2009 6:04 PM >>> To: >>> Subject: Re: LF: Re: WSPR 503.5 >>> >>>> >>>> On Sun, 25 Jan 2009 17:40:27 +0000 >>>> Andy Talbot wrote: >>>> >>>>> Is there some sort of unofficial bandplan on this band? >>>> >>>> Oh no! >>>> >>>> Please let's not get into this again.... >>>> >>>> At the moment there is no bandplan, but general concensus would >>>> indicate "beacons at the band edges - real QSOs in the middle". >>>> >>>> The current WSPR activity around 503.5 (502.0 dial) seems reasonable, >>>> although moving up a few hundred Hz wouldn't hurt, say to 502.3 dial >>>> which gives a 200Hz window at 503.7 - 503.9 >>>> >>>> There are often CW mode beacons near the bottom of the band - GI4DPE, >>>> GW3UEP and others, and it's convenient to have them there - it allows >>>> monitoring them and SK6RUD concurrently. >>>> >>>> >>>> That's just my view on how things have evolved. >>>> >>>> "Real Man's CW" seems to live around 502.63 >>>> >>>> John >>>> GM4SLV >>>> >>>> >>>> >>> >>> >>> >>>> >>>> No virus found in this incoming message. >>>> Checked by AVG - http://www.avg.com >>>> Version: 8.0.176 / Virus Database: 270.10.13/1914 - Release Date: >>>> 1/24/2009 20:40 >>>> >>> >>> >>> >>> >> >> >> >>> >>> No virus found in this incoming message. >>> Checked by AVG - http://www.avg.com >>> Version: 8.0.176 / Virus Database: 270.10.13/1914 - Release Date: >>> 1/24/2009 20:40 >>> >> >> >> > > > > > No virus found in this incoming message. > Checked by AVG - http://www.avg.com > Version: 8.0.176 / Virus Database: 270.10.13/1915 - Release Date: > 1/25/2009 18:13 >