Return-Path: Received: from rly-me08.mx.aol.com (rly-me08.mail.aol.com [172.20.83.42]) by air-me06.mail.aol.com (v125.7) with ESMTP id MAILINME063-9ce4af6e1ae158; Sun, 08 Nov 2009 10:20:26 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-me08.mx.aol.com (v125.7) with ESMTP id MAILRELAYINME082-9ce4af6e1ae158; Sun, 08 Nov 2009 10:20:16 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1N79Xs-0006p3-QW for rs_out_1@blacksheep.org; Sun, 08 Nov 2009 15:19:12 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1N79Xs-0006ou-85 for rsgb_lf_group@blacksheep.org; Sun, 08 Nov 2009 15:19:12 +0000 Received: from mtaout01-winn.ispmail.ntl.com ([81.103.221.47]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1N79Wu-0000zF-6m for rsgb_lf_group@blacksheep.org; Sun, 08 Nov 2009 15:18:13 +0000 Received: from know-smtpout-1.server.virginmedia.net ([62.254.123.1]) by mtaout01-winn.ispmail.ntl.com (InterMail vM.7.08.04.00 201-2186-134-20080326) with ESMTP id <20091108151905.HSRB17029.mtaout01-winn.ispmail.ntl.com@know-smtpout-1.server.virginmedia.net> for ; Sun, 8 Nov 2009 15:19:05 +0000 Received: from [86.27.93.99] (helo=jimdesk) by know-smtpout-1.server.virginmedia.net with esmtp (Exim 4.63) (envelope-from ) id 1N79Xk-0005UN-Vq for rsgb_lf_group@blacksheep.org; Sun, 08 Nov 2009 15:19:05 +0000 From: "James Cowburn" To: Date: Sun, 8 Nov 2009 15:19:01 -0000 Message-ID: <001b01ca6086$cd0966b0$0617aac0@jimdesk> MIME-Version: 1.0 X-Mailer: Microsoft Office Outlook 11 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3350 Thread-Index: AcpghsvF3O/FUKyBTE+0SEWKcbALHA== X-Cloudmark-Analysis: v=1.0 c=1 a=Eps_Ghm3EGtr7jF7nUIA:9 a=g-R94TfW7Gh0stLosyMA:7 a=yew2KIE3PiFnGWLxW_JCNTBaR98A:4 a=SSmOFEACAAAA:8 a=2Y_AYPvP-KM97D4rTIYA:9 a=kG40DQDcz4MwQ-Z5wtQA:7 a=yKdwwVG_gA7ewF7Dufe-fckQOn4A:4 X-Karma: unknown: X-Spam-Score: 0.3 (/) X-Spam-Report: autolearn=disabled,HTML_FONT_BIG=0.256,HTML_MESSAGE=0.001 Subject: LF: Losses due to ant in tree? Content-Type: multipart/alternative; boundary="----=_NextPart_000_001C_01CA6086.CD0966B0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.2 required=5.0 tests=HTML_60_70,HTML_FONT_BIG, 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 ------=_NextPart_000_001C_01CA6086.CD0966B0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi All, The vertical 5m section of my inverted L runs up into the branches of a silver birch tree. The wire goes over a large bough at 5m or so and then comes out of the branches for some 22m down to a 4m high pole attached to the garage. Has anyone a guesstimation of the losses in signal caused by running the wire through the tree? Using vertload and tophat2 I calculate the antenna to be around 0.25% efficient but this assumes it is in free space. Can anyone suggest a figure for the additional loss due to tree heating! The vertical element is actually sloping at about 20 degree from the tree down to the loading coil. The length is nearer 6metres but the vertical height over ground at the bough is about 5m. (Santa may be bringing me a set of swaged poles with which to build mark 2, well away from the silver birch!) With best regards Jim Dr. James Cowburn G7NKS ------=_NextPart_000_001C_01CA6086.CD0966B0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Hi All,

 

The vertical 5m section of my inverted= L runs up into the branches of a silver birch tree.  The wire goes over a large boug= h at 5m or so and then comes out of the branches for some 22m down to a 4m high pole= attached to the garage.

 

Has anyone a guesstimation of the losse= s in signal caused by running the wire through the tree?

 

Using vertload and tophat2 I calculate= the antenna to be around 0.25% efficient but this assumes it is in free space.  Can= anyone suggest a figure for the additional loss due to tree heating!

 

The vertical element is actually slopin= g at about 20 degree from the tree down to the loading coil.  The length is nearer 6me= tres but the vertical height over ground at the bough is about 5m.

 

(Santa may be bringing me a set of swag= ed poles with which to build mark 2, well away from the silver birch!)

 

With best regards

 

 

Jim=

 

 

Dr. James Cowburn G7NKS

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