Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mh04.r1000.mx.aol.com (Internet Inbound) with ESMTP id ED23B38000117; Thu, 26 Jul 2012 16:51:44 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SuV1F-0007yx-M6 for rs_out_1@blacksheep.org; Thu, 26 Jul 2012 21:50:49 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SuV1F-0007yo-5M for rsgb_lf_group@blacksheep.org; Thu, 26 Jul 2012 21:50:49 +0100 Received: from relay.uni-heidelberg.de ([129.206.100.212]) by relay1.thorcom.net with esmtps (TLSv1:AES256-SHA:256) (Exim 4.77) (envelope-from ) id 1SuV1D-0005Mv-CL for rsgb_lf_group@blacksheep.org; Thu, 26 Jul 2012 21:50:48 +0100 Received: from freitag.iup.uni-heidelberg.de (freitag.iup.uni-heidelberg.de [129.206.29.204]) by relay.uni-heidelberg.de (8.14.1/8.14.1) with ESMTP id q6QKojaN018193 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Thu, 26 Jul 2012 22:50:45 +0200 Received: from [129.206.22.206] (pc206.iup.uni-heidelberg.de [129.206.22.206]) by freitag.iup.uni-heidelberg.de (8.12.11.20060308/8.11.2) with ESMTP id q6QKojvn003662 for ; Thu, 26 Jul 2012 22:50:45 +0200 Message-ID: <5011AD16.5000706@iup.uni-heidelberg.de> Date: Thu, 26 Jul 2012 22:48:22 +0200 From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.1.8) Gecko/20100227 Thunderbird/3.0.3 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <50113D08.8020407@iup.uni-heidelberg.de> In-Reply-To: X-Spam-Score: -0.7 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Hello Warren, Am 26.07.2012 19:39, schrieb Warren Ziegler: > Stefan, > I imagine that a LF or VLF small vertical is a relatively high-Q > circuit, how do you manage to keep the kite vertical in resonance and > matched while the kite bounces around in the wind? > Most of the time the kite was quite stable, i.e. the angle and so the C did not change significantly. The antenna current is stable within a 10% limit. When the wind was poor in some situations, the kite drops to a lower angle. Then the falling ERP is rather affected by the lower effective height than by the changing current. The current (say 1A on 8970 Hz) can easyly drop to 400 mA when the angle changes from 80 deg to 40 deg. One method is to compensate this by turning the variometer from time to time or you can use a working point of the variometer that uses a slightly to low L. Then the antenna current does not reduce when the kite falls (in certain limits of course). This is the case because the little generator that i used (up to 550 W RF power in the best times) can be seen as something like a constant power source. So if the kite falls then slightly, the working point moves to the peak of the resonance curve and the rotation speed is somewhat lowered. It was funny to observe this effect for many hours on the field :-) But normally the movement of the wire does not strongly change the antenna current. [...] Content analysis details: (-0.7 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/, low trust [129.206.100.212 listed in list.dnswl.org] -0.0 T_RP_MATCHES_RCVD Envelope sender domain matches handover relay domain X-Scan-Signature: b77892ad90d0261eaf071f4f6cf31464 Subject: Re: LF: Kites Content-Type: text/plain; charset=ISO-8859-1; format=flowed 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=0.0 required=5.0 tests=none 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-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:459995872:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d60d85011ade02458 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Hello Warren, Am 26.07.2012 19:39, schrieb Warren Ziegler: > Stefan, > I imagine that a LF or VLF small vertical is a relatively high-Q > circuit, how do you manage to keep the kite vertical in resonance and > matched while the kite bounces around in the wind? > Most of the time the kite was quite stable, i.e. the angle and so the C did not change significantly. The antenna current is stable within a 10% limit. When the wind was poor in some situations, the kite drops to a lower angle. Then the falling ERP is rather affected by the lower effective height than by the changing current. The current (say 1A on 8970 Hz) can easyly drop to 400 mA when the angle changes from 80 deg to 40 deg. One method is to compensate this by turning the variometer from time to time or you can use a working point of the variometer that uses a slightly to low L. Then the antenna current does not reduce when the kite falls (in certain limits of course). This is the case because the little generator that i used (up to 550 W RF power in the best times) can be seen as something like a constant power source. So if the kite falls then slightly, the working point moves to the peak of the resonance curve and the rotation speed is somewhat lowered. It was funny to observe this effect for many hours on the field :-) But normally the movement of the wire does not strongly change the antenna current. OK? 73, Stefan/DK7FC