Return-Path: Received: from rly-ma06.mx.aol.com (rly-ma06.mail.aol.com [172.20.116.50]) by air-ma01.mail.aol.com (v121_r4.4) with ESMTP id MAILINMA013-8b6493a6462271; Sat, 06 Dec 2008 06:39:30 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-ma06.mx.aol.com (v121_r4.4) with ESMTP id MAILRELAYINMA068-8b6493a6462271; Sat, 06 Dec 2008 06:39:15 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1L8vV2-00065T-7t for rs_out_1@blacksheep.org; Sat, 06 Dec 2008 11:39:04 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1L8vV1-00065K-HK for rsgb_lf_group@blacksheep.org; Sat, 06 Dec 2008 11:39:03 +0000 Received: from imo-m11.mx.aol.com ([64.12.143.99] helo=imo-m11.mail.aol.com) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1L8vV0-00080S-4V for rsgb_lf_group@blacksheep.org; Sat, 06 Dec 2008 11:39:03 +0000 Received: from G4gvw@aol.com by imo-m11.mx.aol.com (mail_out_v39.1.) id l.d5f.3d0ff750 (37062) for ; Sat, 6 Dec 2008 06:38:50 -0500 (EST) Received: from smtprly-db03.mx.aol.com (smtprly-db03.mx.aol.com [205.188.249.154]) by cia-db04.mx.aol.com (v121_r5.1) with ESMTP id MAILCIADB048-5c42493a643c1bb; Sat, 06 Dec 2008 06:38:50 -0500 Received: from WEBMAIL-MY11 (webmail-my11.sim.aol.com [64.12.108.22]) by smtprly-db03.mx.aol.com (v121_r5.1) with ESMTP id MAILSMTPRLYDB038-5c42493a643c1bb; Sat, 06 Dec 2008 06:38:36 -0500 References: <007601c95709$acc95e50$0301a8c0@mal769a60aa920> To: rsgb_lf_group@blacksheep.org Date: Sat, 06 Dec 2008 06:38:36 -0500 In-Reply-To: <007601c95709$acc95e50$0301a8c0@mal769a60aa920> X-MB-Message-Source: WebUI MIME-Version: 1.0 From: g4gvw@aol.com X-MB-Message-Type: User X-Mailer: AOL Webmail 39997-STANDARD Received: from 92.1.230.132 by WEBMAIL-MY11.sysops.aol.com (64.12.108.22) with HTTP (WebMailUI); Sat, 06 Dec 2008 06:38:36 -0500 Message-Id: <8CB25AE4F6C9310-1114-ABC@WEBMAIL-MY11.sysops.aol.com> X-Spam-Flag:NO X-Spam-Score: 0.8 (/) X-Spam-Report: autolearn=disabled,FORGED_AOL_TAGS=0.281,HTML_MESSAGE=0.001,NO_REAL_NAME=0.55,UNPARSEABLE_RELAY=0.001 Subject: Re: LF: Re: E field active antennas Content-Type: multipart/alternative; boundary="--------MB_8CB25AE4F787ECD_1114_1620_WEBMAIL-MY11.sysops.aol.com" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.3 required=5.0 tests=FORGED_AOL_TAGS,HTML_MESSAGE, NO_REAL_NAME 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-IP: 193.82.116.20 ----------MB_8CB25AE4F787ECD_1114_1620_WEBMAIL-MY11.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii" Mal, With all due respect for your undoubted high opinion of your own professional expertise might I suggest that you perhaps enquire as to Andy's credentials before wasting space/time/bandwidth trying to teach his grandmother to suck eggs. 73 de? Pat g4gvw -----Original Message----- From: mal hamilton To: rsgb_lf_group@blacksheep.org Sent: Fri, 5 Dec 2008 18:45 Subject: LF: Re: E field active antennas Try a piece of wire as long and high as possible and an ATU this is superior to any active antenna or loop for that matter, the loop only helps in a noisy environment, and even then not always.? G3KEV? ? ----- Original Message ----- From: "Andy Talbot" ? To: ? Sent: Friday, December 05, 2008 4:22 PM? Subject: LF: E field active antennas? ? > Having just had to make an active antenna for HF (for gainful? > employment-type work, not Am. radio purposes. The commercially made? > one we've ordered is on five weeks delivery and it was needed before? > yesterday) I was wondering about a helical element.? >? > As the thing had to be resonably lightweight, I made the antenna? > element from copper tape on 15mm plastic water pipe rather than use a? > solid copper tube. Just for a bit of novelty I wound the tape in a? > helix, but then started wondering if doing that would make any? > difference to performance. Normally, helically winding an antenna? > (rubber duck type at V/UHF) only serves to distribute loading? > inductance into a short antenna to make it resonate - unlikely to? > change improve the loss terms at all. But I did wonder if the added? > extra inductance, or increased conductor length (not element length -? > that is 1.2m) would change the performance significantly from a? > straight tube.? >? > Does anyone have any ideas - food for thought if nothing else? The? > base amplifier is one I've used several times before for V/LF up to HF? > based around a J310 source follower running at 20mA with bootstrapped? > input followed by a 2N5109 emiter follower at Ic = 80mA. I may have? > published it way-back-when in the amateur press in the 73kHz days.? > Not the best design judging by some of those published in more recent? > years, but did mean all the components were to hand for an instant? > job.? >? > Andy G4JNT? > www.scrbg.org/g4jnt? >? ? --------------------------------------------------------------------------------? ? ? No virus found in this incoming message.? Checked by AVG - http://www.avg.com? Version: 8.0.176 / Virus Database: 270.9.14/1831 - Release Date: 12/4/2008 9:55 PM? ? ________________________________________________________________________ AOL Email goes Mobile! You can now read your AOL Emails whilst on the move. Sign up for a free AOL Email account with unlimited storage today. ----------MB_8CB25AE4F787ECD_1114_1620_WEBMAIL-MY11.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/html; charset="us-ascii"
Mal,

 With all due respect for your undoubted high opinion of your own professional expertise might I suggest that you perhaps enquire as to Andy's credentials before wasting space/time/bandwidth trying to teach his grandmother to suck eggs.

73 de  Pat g4gvw


-----Original Message-----
From: mal hamilton <g3kevmal@talktalk.net>
To: rsgb_lf_group@blacksheep.org
Sent: Fri, 5 Dec 2008 18:45
Subject: LF: Re: E field active antennas

Try a piece of wire as long and high as possible and an ATU this is superior to any active antenna or loop for that matter, the loop only helps in a noisy environment, and even then not always. 
G3KEV 
 
----- Original Message ----- From: "Andy Talbot" <andy.g4jnt@googlemail.com> 
To: <rsgb_lf_group@blacksheep.org> 
Sent: Friday, December 05, 2008 4:22 PM 
Subject: LF: E field active antennas 
 
> Having just had to make an active antenna for HF (for gainful 
> employment-type work, not Am. radio purposes. The commercially made 
> one we've ordered is on five weeks delivery and it was needed before 
> yesterday) I was wondering about a helical element. 
> 
> As the thing had to be resonably lightweight, I made the antenna 
> element from copper tape on 15mm plastic water pipe rather than use a 
> solid copper tube. Just for a bit of novelty I wound the tape in a 
> helix, but then started wondering if doing that would make any 
> difference to performance. Normally, helically winding an antenna 
> (rubber duck type at V/UHF) only serves to distribute loading 
> inductance into a short antenna to make it resonate - unlikely to 
> change improve the loss terms at all. But I did wonder if the added 
> extra inductance, or increased conductor length (not element length - 
> that is 1.2m) would change the performance significantly from a 
> straight tube. 
> 
> Does anyone have any ideas - food for thought if nothing else? The 
> base amplifier is one I've used several times before for V/LF up to HF 
> based around a J310 source follower running at 20mA with bootstrapped 
> input followed by a 2N5109 emiter follower at Ic = 80mA. I may have 
> published it way-back-when in the amateur press in the 73kHz days. 
> Not the best design judging by some of those published in more recent 
> years, but did mean all the components were to hand for an instant 
> job. 
> 
> Andy G4JNT 
> www.scrbg.org/g4jnt 
> 
 
-------------------------------------------------------------------------------- 
 
 
No virus found in this incoming message. 
Checked by AVG - http://www.avg.com 
Version: 8.0.176 / Virus Database: 270.9.14/1831 - Release Date: 12/4/2008 9:55 PM 
 
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