Return-Path: X-Spam-DCC: paranoid 1170; 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=-1.0 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_RCVD_HELO,SUBJ_RE_NUM 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 t8TDQjaq006429 for ; Tue, 29 Sep 2015 15:26:45 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Zgusb-0000sj-8Y for rs_out_1@blacksheep.org; Tue, 29 Sep 2015 14:23:37 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Zgusa-0000sa-W3 for rsgb_lf_group@blacksheep.org; Tue, 29 Sep 2015 14:23:36 +0100 Received: from smarthost01c.mail.zen.net.uk ([212.23.1.5]) by relay1.thorcom.net with esmtp (Exim 4.86) (envelope-from ) id 1Zgure-0005Hd-Gv for rsgb_lf_group@blacksheep.org; Tue, 29 Sep 2015 14:23:35 +0100 Received: from [82.70.254.222] (helo=OfficeWin7.lan) by smarthost01c.mail.zen.net.uk with esmtp (Exim 4.80) (envelope-from ) id 1ZgurO-000Cc7-Rd for rsgb_lf_group@blacksheep.org; Tue, 29 Sep 2015 13:22:23 +0000 Date: Tue, 29 Sep 2015 14:22:22 +0100 From: Chris Wilson Organization: Gatesgarth Developments X-Priority: 3 (Normal) Message-ID: <88588474.20150929142222@chriswilson.tv> To: rsgb_lf_group@blacksheep.org In-Reply-To: <560A8C7E.27027.38EA9D@roelof.ndb.demon.nl> References: <453589076.20150929131349@chriswilson.tv>, <303E79ED08714B6EA8827B2A47AB88A0@gnat> <560A8C7E.27027.38EA9D@roelof.ndb.demon.nl> MIME-Version: 1.0 X-Originating-smarthost01c-IP: [82.70.254.222] X-Scan-Signature: 7ab87d4d3ea1d9dcb73a78e83fe4d608 Subject: Re[2]: LF: Re: Active antennas on 136kHz, additional wire needed? Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit 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 10.1.3.10 Status: O X-Status: X-Keywords: X-UID: 4206 Hello rsgb, Tuesday, September 29, 2015 > Hello Chris, > The "PCB-antenna" is equivalent to a 1 feet rod and though counter > intuitive, adding one won't help. > As with all active whip designs, at VLF / LF / MW and lower HF the > whip is NOT the antenna. > How the pa0rdt-Mini-Whip© works, can be found here: > http://wwwhome.cs.utwente.nl/~ptdeboer/ham/tn/tn07.html > Though some knowledgeable people don't agree, I have put the theory > to the test and build a battery powered mini-whip with the battery > included in the antenna housing. The rf was transported by a > optical fibre link. The antenna was mounted on a non conducting > fibre glass pole. > Nothing was received at all with this set up, until I put a coax > cable up the mast ending 5 cm below the antenna. There was no > connection between this cable and the circuit board, whatsoever. > The shield of the coax cable was connected to a ground stake at the > bottom of the mast and it provided the necessary ground reference > for the ohterwise isolated antenna. > I hope this helps. > 73, > Roelof Bakker, pa0rdt > N.B. Rather than building one for one's own use, which is no problem > at all, I am sorry to find that some people are making money from a > copywrighted design. (Readily build antennas are available from the > designer for those unable or unwilling to build one.) Thanks for the info "from the horse's mouth", and I sympathize with your predicament of people selling your design commercially. In this case I just received a gift from my pal, he has little electrical knowledge of radio stuff, he must have remembered me saying I would like to try an active antenna and looked on Ebay. It was my intention to make one, but he beat me to it, sorry! It's an intriguing thing and I look forward to trying it out. -- Best regards, Chris mailto:chris@chriswilson.tv