Return-Path: X-Spam-DCC: paranoid 1290; 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=-0.1 required=5.0 tests=BAYES_00,DNS_FROM_AHBL_RHSBL, FORGED_HOTMAIL_RCVD,HTML_MESSAGE 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 u196Ep0u025718 for ; Tue, 9 Feb 2016 07:14:52 +0100 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1aT1QY-0006U1-2Q for rs_out_1@blacksheep.org; Tue, 09 Feb 2016 06:05:30 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1aT1QX-0006Ts-8I for rsgb_lf_group@blacksheep.org; Tue, 09 Feb 2016 06:05:29 +0000 Received: from blu004-omc1s8.hotmail.com ([65.55.116.19]) by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-SHA384:256) (Exim 4.86) (envelope-from ) id 1aT1PS-0007Iz-Nd for rsgb_lf_group@blacksheep.org; Tue, 09 Feb 2016 06:05:28 +0000 Received: from BLU185-W13 ([65.55.116.7]) by BLU004-OMC1S8.hotmail.com over TLS secured channel with Microsoft SMTPSVC(7.5.7601.23008); Mon, 8 Feb 2016 22:04:06 -0800 X-TMN: [SgU7mEA462TWJz3WN4HOw9hc658MwVOz] X-Originating-Email: [hellozerohellozero@hotmail.com] Message-ID: From: Laurence KL7 L To: "rsgb_lf_group@blacksheep.org" Date: Mon, 8 Feb 2016 21:04:05 -0900 Importance: Normal In-Reply-To: <013701d162a4$4c6aa0b0$e53fe210$@comcast.net> References: <00a801d161fd$1b66ff10$5234fd30$@comcast.net> <56B7D569.1030908@virginbroadband.com.au>,<013701d162a4$4c6aa0b0$e53fe210$@comcast.net> MIME-Version: 1.0 X-OriginalArrivalTime: 09 Feb 2016 06:04:06.0517 (UTC) FILETIME=[AF267250:01D162FF] X-Scan-Signature: 80dfd4418e586cee7526d670ae10acbc Content-Type: multipart/alternative; boundary="_d872d1f9-d00b-40ac-b147-4bb81a554f35_" Subject: RE: LF: RE: Vlf ot Penguins and awesomes - More 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: 6756 --_d872d1f9-d00b-40ac-b147-4bb81a554f35_ Content-Type: text/plain; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable Edgar/Jim -- Ive come up with an initial transformer design of 25T pri (1 o= hm 1 mH) and around 170 turns sec - typically their LNA are around 520 ohm = Z input but my simple bi polar is appx 50 ohm. As ever the primary needs t= o be low R as possible therefore fairly thick as can be wound on a pot cor= e and the secondary around #30 =3D I note their design appears to be Z primary 1 ohm and input Z to amp 520 so= 24/528T 16:1 ratio well n the AWESOME anyway - thanks again Will give it a go.....as ever the difference in near field E probe to B/Mag= is amazing -cant hear the 8kHzdog fence pulser on the Eprobe (still my be= st VLF DX antennna here) but its a good 599 on the 1mH/1Ohm 10m sided 5T lo= op.... I wish I had paid for attention to Dr Piggott nearly 40 years ago! Laurence KL7L WE2XPQ From: hvanesce@comcast.net To: rsgb_lf_group@blacksheep.org Date: Mon=2C 8 Feb 2016 14:09:55 -0500 Subject: RE: LF: RE: Vlf ot Penguins and awesomes Edgar=2C Excellent find=2C thanks for posting=2C hope it answers Laurence= =92s questions. A comment regarding the summary (last paragraph) on .pdf pa= ge 32=2C original document page 27: prototype transformer C_s can deviate c= onsiderably from initial design value especially if a simplified model for = C_s is used in the design or design spec for the magnet wire is not control= led for insulation type and winding/layering method. If a transformer model= ing tool is not available=2C the old Radiotron Engineer=92s Handbook has so= me helpful models. Note Paschal=92s comment in a related context (C_a of = loop) in paragraph 1=2C .pdf pg 40=2C original document pg 35:=93...it is = difficult to calculate the value of C_a =85easier to build and measure= =94.In the case of the matching transformer=2C using a transformer model th= at has a reasonable approximation for C_s could save a fair amount of test/= rewind time on the way to a VLF receiver with sensitivity of 0.5uV/m-Hz^1/2= (measured=2C Fig 8.5=2C .pdf pg 78) Of interest in context of C_= s:Item 4=2C .pdf page 44=2C original document page 40=3B and last paragrap= h=2C same pageItem 2 (packing density)=2C .pdf page 47=2C original documen= t page 43Item 4=2C .pdf page 47=2C original document page 43Paragraph 2 (L= itz wire tradeoffs)=2C .pdf page 49=2C original document page 45Last paragr= aph on .pdf page 52=2C original document page 56 (in the context of high-im= pedance preamps): =93C_s forms a tuned circuit=85 (therefore) low-impedanc= e amplifiers are a much better practical solution=94 I wonder if page 38 of= the original document is blank. It=92s not included in the .pdf document (= which is why the offset between .pdf page number and original document page= number changes after original document page 37) Thanks for posting the lin= k=3B hope it answers Laurence=92s questions=3B I had been looking for this = article off and on since seeing a reference to it some years ago. 73=2C Jim= AA5BW From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_grou= p@blacksheep.org] On Behalf Of edgar Sent: Sunday=2C February 7=2C 2016 6:38 PM To: rsgb_lf_group@blacksheep.org Subject: Re: LF: RE: Vlf ot Penguins and awesomes Hi Laurence=2C You probably have this=2C but in case you do not. http://traktoria.org/files/radio/antenna/VLF/the_design_of_broad-band_vlf_r= eceivers_with_air-core_loop_antennas.pdf It may not answer your questions. Regards=2C Edgar Moonah=2C Tasmania. = --_d872d1f9-d00b-40ac-b147-4bb81a554f35_ Content-Type: text/html; charset="Windows-1252" Content-Transfer-Encoding: quoted-printable
Edgar/Jim -- Ive come up with an= initial transformer design of 25T pri (1 ohm 1 mH) and around 170 turns se= c - typically their LNA are around 520 ohm Z input but my simple  =3Bbi= polar is appx 50 ohm. As ever the primary needs to be low R as possible th= erefore  =3Bfairly thick as can be wound on a pot core and the secondar= y around #30 =3D

I note their design appears to be Z pri= mary 1 ohm and input Z to amp 520 so 24/528T 16:1 ratio well n the AWESOME = anyway - thanks again

Will give it a go.....as eve= r the difference in near field E probe to B/Mag  =3Bis amazing -cant he= ar the 8kHzdog fence pulser on the Eprobe (still my best VLF DX antennna he= re) but its a good 599 on the 1mH/1Ohm 10m sided 5T loop....

=
I wish I had paid for attention to Dr Piggott nearly 40 years ag= o!



Laurence KL7L &nb= sp=3BWE2XPQ

From: hvanesce@comcast.net<= br>To: rsgb_lf_group@blacksheep.org
Date: Mon=2C 8 Feb 2016 14:09:55 -05= 00
Subject: RE: LF: RE: Vlf ot Penguins and awesomes

Edgar=2C

 =3B

Excelle= nt find=2C thanks for posting=2C hope it answers Laurence=92s questions.

 =3B

A comment regarding the summary (last paragraph) on .p= df page 32=2C original document page 27: prototype transformer C_s can devi= ate considerably from initial design value especially if a simplified model= for C_s is used in the design or design spec for the magnet wire is not co= ntrolled for insulation type and winding/layering method. If a transformer = modeling tool is not available=2C the old Radiotron Engineer=92s Handbook h= as some helpful models.  =3B

 =3B

Note Paschal=92s comme= nt in a related context (C_a of loop) in paragraph 1=2C  =3B.pdf pg 40= =2C original document pg 35:

=93...it is difficult to calculate the va= lue of C_a =3B =3B  =3B=85easier to build and measure=94.

= In the case of the matching transformer=2C using a transformer model that h= as a reasonable approximation for C_s could save a fair amount of test/rewi= nd time on the way to a VLF receiver with sensitivity of 0.5uV/m-Hz^1/2 (me= asured=2C Fig 8.5=2C .pdf pg 78)  =3B =3B =3B =3B =3B&n= bsp=3B =3B =3B =3B

 =3B

Of interest in context of= C_s:

Item 4=2C  =3B.pdf page 44=2C original document page 40=3B= and last paragraph=2C same page

Item 2 (packing density)=2C  =3B.= pdf page 47=2C original document page 43

Item 4=2C  =3B.pdf page 4= 7=2C original document page 43

Paragraph 2 (Litz wire tradeoffs)=2C .p= df page 49=2C original document page 45

Last paragraph on .pdf page 52= =2C original document page 56 (in the context of high-impedance preamps): &= nbsp=3B=93C_s forms a tuned circuit=85 (therefore) low-impedance amplifiers= are a much better practical solution=94

 =3B

I wonder if p= age 38 of the original document is blank. It=92s not included in the .pdf d= ocument (which is why the offset between .pdf page number and original docu= ment page number changes after original document page 37)

 =3B

Thanks for posting the link=3B hope it answers Laurence=92s questions=3B = I had been looking for this article off and on since seeing a reference to = it some years ago.

 =3B

73=2C

 =3B

Jim AA5BW <= /span>

 =3B

<= span style=3D"font-size:10.0pt=3Bfont-family:"=3BTahoma"=3B=2C"= =3Bsans-serif"=3B=3Bcolor:windowtext=3B">From: owner-rsgb_lf_group@blacksheep.org [mailto= :owner-rsgb_lf_group@blacksheep.org] On Behalf Of edgar
Sent:<= /b> Sunday=2C February 7=2C 2016 6:38 PM
To: rsgb_lf_group@blacks= heep.org
Subject: Re: LF: RE: Vlf ot Penguins and awesomes=

 =3B

Hi Laurence=2C

You probably have this=2C but in case you= do not.

http://traktoria.org/files/radio/ant= enna/VLF/the_design_of_broad-band_vlf_receivers_with_air-core_loop_antennas= .pdf

It may not answer your questions.

Regards=2C EdgarMoonah=2C Tasmania.

= --_d872d1f9-d00b-40ac-b147-4bb81a554f35_--