Return-Path: Received: from rly-dc09.mx.aol.com (rly-dc09.mail.aol.com [172.19.136.38]) by air-dc01.mail.aol.com (v121_r4.4) with ESMTP id MAILINDC012-b40497cec1f146; Sun, 25 Jan 2009 17:48:23 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-dc09.mx.aol.com (v121_r4.4) with ESMTP id MAILRELAYINDC094-b40497cec1f146; Sun, 25 Jan 2009 17:48:01 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1LRDlG-0008Nr-55 for rs_out_1@blacksheep.org; Sun, 25 Jan 2009 22:47:26 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1LRDlF-0008Ni-ER for rsgb_lf_group@blacksheep.org; Sun, 25 Jan 2009 22:47:25 +0000 Received: from smtp816.mail.ird.yahoo.com ([77.238.189.16]) by relay3.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1LRDlE-0001AK-EZ for rsgb_lf_group@blacksheep.org; Sun, 25 Jan 2009 22:47:25 +0000 Received: (qmail 40512 invoked from network); 25 Jan 2009 22:47:18 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=btopenworld.com; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:Message-ID:From:To:References:In-Reply-To:Subject:Date:MIME-Version:Content-Type:Content-Transfer-Encoding:X-Priority:X-MSMail-Priority:X-Mailer:X-MimeOLE; b=doUzbAo0Wp67VJj2Kfu2bPUQcq+6lR/WD6YpsXfeGnTtRxWClF7xIeT/wiSnORGLVivYUH4qCGhtK0DDypEHXaHOHKI3PABKizTzFVmQacRERtKY7lNlOXWdYWjaep3n8RdRwoDNLZoClHFnH1i6vKxY4ZObx19k14uhbXcN1j0= ; Received: from unknown (HELO JimPC) (james.moritz@86.134.108.92 with login) by smtp816.mail.ird.yahoo.com with SMTP; 25 Jan 2009 22:47:18 -0000 X-YMail-OSG: vs2UJgsVM1ngm54tXvU_FDNNC8zdA8D2oO33Qph.8_uAad708iB2BnCs.7XoRAAajSn8yBhCsnu3XRNgIGCB9B0uBu0eqoq9mOtHoG8jemDbVFR.fhxa87F.RRCgF4MaEOyR1cU3cxeMOMvKlBuRltRGw3hrQeoBPPvgihgyw5XxfMvbprlrJUTfpNCq5CbPBU.cXoMRD6UXE.GsbOeOtWCvsQ-- X-Yahoo-Newman-Property: ymail-3 Message-ID: From: "James Moritz" 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$6401a8c0@asus> In-Reply-To: <00f101c97f2d$e530b440$6401a8c0@asus> Date: Sun, 25 Jan 2009 22:47:18 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6001.18000 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: 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 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 >> > > >