Return-Path: X-Spam-DCC: paranoid 1481; Body=2 Fuz1=2 Fuz2=2 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-0.7 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, HTML_MESSAGE,RATWARE_GECKO_BUILD,SPF_PASS autolearn=no version=3.1.3 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by paranoid.lipkowski.org (8.13.7/8.13.7) with ESMTP id u76GuNlE025982 for ; Sat, 6 Aug 2016 18:56:23 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1bW4lk-0001as-Bu for rs_out_1@blacksheep.org; Sat, 06 Aug 2016 17:48:16 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1bW4lj-0001aj-Dw for rsgb_lf_group@blacksheep.org; Sat, 06 Aug 2016 17:48:15 +0100 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 1bW4lh-0001m1-JB for rsgb_lf_group@blacksheep.org; Sat, 06 Aug 2016 17:48:14 +0100 Received: from submission (posteo.de [89.146.220.130]) by mout02.posteo.de (Postfix) with ESMTPS id F10E820464 for ; Sat, 6 Aug 2016 18:48:10 +0200 (CEST) Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 3s68kK5dxQzytM for ; Sat, 6 Aug 2016 18:48:08 +0200 (CEST) Message-ID: <57A614C8.8060302@posteo.de> Date: Sat, 06 Aug 2016 18:48:08 +0200 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: <5772DAC0.7080001@df3lp.de> <5773CA12.50009@posteo.de> <5773D53A.5070900@abelian.org> <577B9E96.8070807@posteo.de> <577CA9CF.6070303@abelian.org> <578BC20F.60905@posteo.de> <579D29F1.4020003@posteo.de> <579F892C.9080603@posteo.de> <57A4946B.8080503@posteo.de> In-Reply-To: <57A4946B.8080503@posteo.de> X-Scan-Signature: ac0f6ff1af52b6036ac1f4fe0c2bd52c Subject: ULF: 44 mA into my antenna on 2970 Hz Content-Type: multipart/alternative; boundary="------------090800050605020206090209" 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 2.56 on 10.1.3.11 Status: O X-Status: X-Keywords: X-UID: 8513 This is a multi-part message in MIME format. --------------090800050605020206090209 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi all, Since a few hours i'm running a higher power on 2970 Hz. My own grabber shows an increase of 5 dB. The measured antenna current is now *44 mA*, see https://dl.dropboxusercontent.com/u/19882028/ULF/44.4mA%402970Hz.jpg (with the Heidelberg castle in the background ;-) ). This should mean 5 kV on the antenna and *250 nW ERP*. A suitable capacitor is now in parallel to the antenna. It seems to have a high temperature coefficient. I'm trying to stabilize the working point of the system to keep the current constant... 270 mA is now running though the yoghurt cup coil which was used on 6.47 kHz in the past. Maybe the internal iron powder cores begin to saturate slightly at this current and frequency? This could explain the higher losses and the lower resulting voltage or antenna current. Actually i did expect 57 mA... 73, Stefan --------------090800050605020206090209 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi all,

Since a few hours i'm running a higher power on 2970 Hz. My own grabber shows an increase of 5 dB. The measured antenna current is now 44 mA, see https://dl.dropboxusercontent.com/u/19882028/ULF/44.4mA%402970Hz.jpg (with the Heidelberg castle in the background ;-) ). This should mean 5 kV on the antenna and 250 nW ERP.
A suitable capacitor is now in parallel to the antenna. It seems to have a high temperature coefficient. I'm trying to stabilize the working point of the system to keep the current constant...
270 mA is now running though the yoghurt cup coil which was used on 6.47 kHz in the past. Maybe the internal iron powder cores begin to saturate slightly at this current and frequency? This could explain the higher losses and the lower resulting voltage or antenna current. Actually i did expect 57 mA...

73, Stefan
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