Return-Path: Received: (qmail 20243 invoked from network); 29 Mar 2000 11:38:46 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by dimple.core.plus.net.uk with SMTP; 29 Mar 2000 11:38:46 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 12aGfu-00058g-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 29 Mar 2000 12:30:14 +0100 Received: from mail04.hostcenter.com ([195.186.64.57]) by post.thorcom.com with smtp (Exim 3.02 #1) id 12aGfq-00058M-00 for rsgb_lf_group@blacksheep.org; Wed, 29 Mar 2000 12:30:10 +0100 Received: from www303.hostcenter.com (195.186.64.84) by mail04.hostcenter.com (RS ver 1.0.53) with SMTP id 02255367 for ; Wed, 29 Mar 2000 13:29:45 +0200 (MDT) Message-ID: <38E2686D.26F5CA2C@phonakcom.ch> X-Priority: 3 X-MSMail-Priority: Normal Date: Wed, 29 Mar 2000 12:32:45 -0800 From: "Toni Baertschi" Organization: Phonak Communications AG X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Mailer: Mozilla 4.7 [en] (WinNT; I) X-Accept-Language: en MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Re: Re. DECCA Tx References: <000201bf98ec$a45b1680$0da4883e@lvm> <01c501bf98ff$0c451680$6b884fd1@tractorb> <38E1D278.C14B4291@netscapeonline.co.uk> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 8bit X-Loop-Detect: 1 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: A sort of passive amplifier: The low radiated power of the small antenna is captured by the big antenna, maybe 100m away, mysticly amplified and then radiated again - giving a much stronger signal? How does this work? 73 de Toni, HB2ASB g3kev wrote: > Dave Brown wrote: > > > Laurie, > > I think you will find that you need to remove the 300 footer before trying > > the low height antenna- otherwise mutual coupling effects will surely stuff > > things up. > > And at 300 feet you will be getting out of 'very short vertical' territory > > anyway, even on 136. > > At this frequency with both antennas resonant on 136 khz on the same site, the > induced rf from the small vertical into the larger one would distort any > meaningful tests. The antennas would need to be sited several kilometres apart, > when co located one would need to be dismantled while the other one is tested. > I have already tested this by starting off with a 60 ft vertical and progressing > to 120 ft and it certainly made a big difference for the same given rf power > output. Signal reports all over europe confirm this. > G3KEV > > > > > > > 73 > > Dave, ZL3FJ > > > > ----- Original Message ----- > > From: LAWRENCE MAYHEAD > > To: rsgb lf group > > Sent: Wednesday, March 29, 2000 7:32 AM > > Subject: LF: Re. DECCA Tx > > > > The possibility of transmitting from an ex Decca site is very intresting I > > would like to put foreward a suggestion for an experiment.Theory has it that > > the radiation pattern for a much shortened vertical is not dependant on > > height! Some on this reflector disagree.Would it be possible to radiate say > > 1w erp from the 300 foot antenna and the same power from a co-sited very > > short vert similar to those being used by many people, if they used the same > > ground system all the better.Then by transmitting alternately from each > > station we could gather signal reports from many recieving stations both > > near and far,for various times of the day. > > Perhaps then we could settle this argument once and for all.. 73s Laurie.