Return-Path: X-Spam-DCC: paranoid 1102; Body=3 Fuz1=3 Fuz2=3 X-Spam-Checker-Version: SpamAssassin 3.1.3 (2006-06-01) on lipkowski.org X-Spam-Level: X-Spam-Status: No, score=-1.4 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, NO_REAL_NAME 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 t49DDgZp012891 for ; Sat, 9 May 2015 15:13:42 +0200 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Yr4Wy-0004A2-OG for rs_out_1@blacksheep.org; Sat, 09 May 2015 14:11:00 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Yr4Wy-00049t-Gb for rsgb_lf_group@blacksheep.org; Sat, 09 May 2015 14:11:00 +0100 Received: from nina.ucs.mun.ca ([134.153.232.76]) by relay1.thorcom.net with esmtps (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.85) (envelope-from ) id 1Yr4Ww-00036U-6a for rsgb_lf_group@blacksheep.org; Sat, 09 May 2015 14:10:59 +0100 Received: from plato.ucs.mun.ca (plato.ucs.mun.ca [134.153.232.153]) by nina.ucs.mun.ca (8.13.1/8.13.1) with ESMTP id t49DAsSr017515 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Sat, 9 May 2015 10:40:54 -0230 Date: Sat, 9 May 2015 10:40:54 -0230 (NDT) From: jcraig@mun.ca X-X-Sender: jcraig@plato.ucs.mun.ca To: rsgb_lf_group@blacksheep.org In-Reply-To: <554DFC21.7050505@gmail.com> Message-ID: References: <554CD3BD.13112.13127C0@mike.dennison.ntlworld.com> <554DFC21.7050505@gmail.com> MIME-Version: 1.0 X-Scan-Signature: fc152e7304849b9a177649b85aea9f41 Subject: Re: LF: DK7FC VLF probe Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed 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: 3077 Stefan, Thanks for the info and advice. Yes, ferrite beads sound like a good idea. The resistors and caps (1M 100k 68pF 680pF etc) between the FET's are for lowpass or something else? 73 Joe VO1NA On Sat, 9 May 2015, DK7FC wrote: > Hi Joe, > > That choke was just intended to improve the supply voltage stability (low > pass filtering). It's value is not critical. > Meanwhile i've learned that it can be helpful to spend a ferrite bead in > front of the jFETs gate, to prevent VHF oscillations... > I am one of those who prefer to spend one more component here and there, just > to prevent eventual unintended behaviour... > > 73, Stefan > > Am 09.05.2015 02:44, schrieb jcraig@mun.ca: >> Hi Stefan and group, >> >> I am building a probe using your design. Could you >> explain the interstage network and the 470 uH choke? >> >> I hope to use this to detect some 36 km photons. So far, >> using the PA0RDT miniwhip (without the VLF refit) >> and Spectrum Lab has resulted in reception only of >> near field electrostatic and induced artefacts >> ie: my best DX is only 5.2 km. >> >> Best 73 & TNX >> Joe VO1NA >> >> >> >> >> > >