Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, RCVD_IN_DNSWL_MED,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 X-Spam-DCC: EATSERVER: mailn 1166; Body=2 Fuz1=2 Fuz2=2 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by lipkowski.org (8.14.4/8.14.4/Debian-8+deb8u1) with ESMTP id v0I9dqpd019978 for ; Wed, 18 Jan 2017 10:39:54 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1cTme0-0005Sq-L5 for rs_out_1@blacksheep.org; Wed, 18 Jan 2017 09:35:04 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1cTmdz-0005Sh-S0 for rsgb_lf_group@blacksheep.org; Wed, 18 Jan 2017 09:35:03 +0000 Received: from mout02.posteo.de ([185.67.36.66]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256) (Exim 4.87) (envelope-from ) id 1cTmdw-0004Kv-4n for rsgb_lf_group@blacksheep.org; Wed, 18 Jan 2017 09:35:01 +0000 Received: from submission (posteo.de [89.146.220.130]) by mout02.posteo.de (Postfix) with ESMTPS id 4D49420A51 for ; Wed, 18 Jan 2017 10:34:58 +0100 (CET) Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 3v3MJL0491zypM for ; Wed, 18 Jan 2017 10:34:57 +0100 (CET) Message-ID: <587F36C1.5080508@posteo.de> Date: Wed, 18 Jan 2017 10:34:57 +0100 From: DK7FC 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: <0166BDF4-A692-4E83-AA17-DE6FC012EC1F@talktalk.net> <877D570598134B12ADC67A8D874C9F32@AGB> <23DE64E288C84B19B7C9212A6CADFBB8@PCPMF>,<587E6B7A.6090204@posteo.de> ,<587E72D1.3080109@posteo.de> <587E9CEB.7010105@posteo.de> <587EAE7E.8070607@posteo.de> In-Reply-To: <587EAE7E.8070607@posteo.de> X-Scan-Signature: c1f72e5acb1277e013f90c915ad7ad68 Subject: Re: VLF: Carrier on 8270 Hz Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit 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-Scanned-By: MIMEDefang 2.75 Status: RO X-Status: A X-Keywords: X-UID: 10228 Am 18.01.2017 00:53, schrieb DK7FC: > BTW the antenna suddenly dropped. I had the badest thoughts, and still > have. It dropped to about 200 mA arround 22:40 UTC. > The resonance dropped a bit and the Q was much lower then. A visual > inspection showed no sign of a flashover. The PA works well and the > system is now prepared for the next EbNaut transmission on 5170 Hz > tomorrow, as usual. > Oh and my tree is back and will monitor that transmission! > I'll continue to check for a fault on the coil now... I measured the DC resistance, normal. I applied 700 mA DC, no inhomogenious upheating. Why did the resonance frequency drop and why did the Q drop? My latest thought is that it was a heavy partial discharge that started on a developing icicle!? Maybe there was an ice layer somewhere on high potential. Small discharges (corona/arcing...) could have forced the ice layer to melt. This could have formed an icicle which made the discharges stronger at a certain moment. The voltage has been 24.5 kV, not trivial at this frequency. So maybe there is no fault. The discharge would explain the lower resonance frequency and the lower Q. With a partly short cut coil winding, the resonance frequency should have been higher. I should have tested to rise the current slowly from 0 to 600 mA and observe the current during that time. Maybe it would have hold 500 mA before the discharge happened. But it was late in the night and i wanted to stop transmitting anayway. So its something to test in the next days... 73, Stefan