Return-Path: <owner-rsgb_lf_group@blacksheep.org> Received: (qmail 27272 invoked from network); 2 Aug 2003 18:03:03 -0000 Received: from marstons.services.quay.plus.net (212.159.14.223) by netmail00.services.quay.plus.net with SMTP; 2 Aug 2003 18:03:03 -0000 Received: (qmail 12995 invoked by uid 10001); 2 Aug 2003 18:03:02 -0000 Received: from post.thorcom.com (193.82.116.70) by marstons.services.quay.plus.net with SMTP; 2 Aug 2003 18:03:02 -0000 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 4.14) id 19j0iD-0003P4-HR for rsgb_lf_group-outgoing@blacksheep.org; Sat, 02 Aug 2003 19:02:37 +0100 Received: from [212.135.6.11] (helo=smarthost1.mail.uk.easynet.net) by post.thorcom.com with esmtp (Exim 4.14) id 19j0i9-0003Ov-IR for rsgb_lf_group@blacksheep.org; Sat, 02 Aug 2003 19:02:33 +0100 Received: from tnt-5-28.easynet.co.uk ([195.40.200.28] helo=bryan2) by smarthost1.mail.uk.easynet.net with smtp (Exim 4.10) id 19j0i7-000LN1-00 for rsgb_lf_group@blacksheep.org; Sat, 02 Aug 2003 19:02:32 +0100 Message-ID: <002f01c35920$5afc1000$75c428c3@bryan2> From: "captbrian" <captbrian@ukonline.co.uk> To: rsgb_lf_group@blacksheep.org Date: Sat, 2 Aug 2003 18:51:50 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.1 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Subject: Re: LF: Re: 500m drums of coax dipole Content-Type: text/plain; charset=iso-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Spam-Status: No, hits=-1.0 required=5.0tests=ORIGINAL_MESSAGE,QUOTED_EMAIL_TEXTversion=2.55 X-Spam-Checker-Version: SpamAssassin 2.55 (1.174.2.19-2003-05-19-exp) 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: rsgb_lf_group-outgoing@blacksheep.org X-SA-Exim-Scanned: No; SAEximRunCond expanded to false Ah but they have the first 35 feet vertical. I have lately wondered how far one can get on 20m with an equivalent inverted L to scale ie about 4 inches vertical with around 12 inches horizontal. - [ and a few ground rods driven 1" into the lawn ?] . Not an expensive experiment until the final blows up I suppose and any suggestion that the radiation all comes from the feeder I shall stoutly deny. even if the balun is taller than the antenna. Hmm.. back to the drawing board Bryan -----Original Message----- From: Stewart Bryant <stewart.bryant@virgin.net> To: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org> Date: 02 August 2003 17:22 Subject: Re: LF: Re: 500m drums of coax dipole >But compared to 2000m the 10 to 20m that most folks manage is still >small. > >As I write this I look out at the farmers field behind my new house >reasonably high on the north downs. Perhaps I should take a reel of >cable down the edge of his field, and through the woods beyond. >I could not manage a dipole, but perhaps it is worth trying one of the >grounded at both ends, on the ground, loops that were talked about >in the early days. > >Can anyone remember what sort of length one needs to start with? > >Stewart G3YSX > > > >captbrian wrote: >> Is there the slightest evidence that 136 propagates (propogates?) by >> scatter or reflection.? I assume most of a 2" high dipole radiation goes >> straight up to Mars. >> >> Bryan >> -----Original Message----- >> From: G0MRF@aol.com <G0MRF@aol.com> >> To: rsgb_lf_group@blacksheep.org <rsgb_lf_group@blacksheep.org> >> Date: 02 August 2003 11:47 >> Subject: LF: 500m drums of coax? >> >> >> >>> >>>>>Are you making a coax dipole for 136? >>>>> >>>>>73 >>>>>John Rabson G3PAI >>>> >>>I've always wondered about dipoles / loops at 136k? >>>A 'dipole' just lying on rocky ground where the water table is many metres >>>below the surface could be quite effective. The angle of radiation would be >> >> poor >> >>>but the efficiency may not be as bad as first suppossed. One advantage of a >>>big antenna on the ground is that it can't fall down and, for the local >>>planning committe, it's less than 9 feet high. >>> >>>Some time ago I tried to simulate this by making a dipole for 21MHz and had >> >> a >> >>>number of QSOs through it while gradually lowering it's height and >> >> retrimming >> >>>as I went. I managed to work Romania were I sent "Ant dipole 5cm agl". I >>>have no idea what the Romanian though of this madness and he didn't stay >> >> around >> >>>long to find out. >>>Incidentally, at about 2 inches off the ground the antenna was resonant at >>>about 20% less than it's normal 'free space length'. Never did find a big >> >> field >> >>>to try it on 136k. >>> >>>73 >>> >>>David G0MRF >>> >> >> >> >> > > > >