Return-Path: Received: from mtain-dh06.r1000.mx.aol.com (mtain-dh06.r1000.mx.aol.com [172.29.65.26]) by air-da09.mail.aol.com (v128.1) with ESMTP id MAILINDA093-86414baf9ffa26; Sun, 28 Mar 2010 14:29:14 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dh06.r1000.mx.aol.com (Internet Inbound) with ESMTP id 33EE8380000AF; Sun, 28 Mar 2010 14:29:12 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NvxDM-0004Ll-HB for rs_out_1@blacksheep.org; Sun, 28 Mar 2010 19:28:00 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NvxDL-0004Lc-PE for rsgb_lf_group@blacksheep.org; Sun, 28 Mar 2010 19:27:59 +0100 Received: from smtp101.sbc.mail.ac4.yahoo.com ([76.13.13.240]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1NvxDI-0000wk-H9 for rsgb_lf_group@blacksheep.org; Sun, 28 Mar 2010 19:27:59 +0100 Received: (qmail 2455 invoked from network); 28 Mar 2010 18:27:49 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=snet.net; h=Received:X-Yahoo-SMTP:X-YMail-OSG:X-Yahoo-Newman-Property:Reply-To:From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:X-Priority:X-MSMail-Priority:X-Mailer:Importance:X-MIMEOLE:X-MS-TNEF-Correlator:In-Reply-To; b=aWsXEuSrWv4PFXcQUIrBkGKMKR1CYbmWR803queRfdzrJ8T/2W6uuOGcrqi5TCGT5KI8VS5Pnd6uYeiG0E5Q3VyAPPalS2lcsM4u0sVB5W6zeYrfTAJy1Gu6P1tVvqHiuNAFkxV9hTJ+nPDYxJEeozrDpkhRMWWTd+R0oAMkav4= ; Received: from adsl-76-192-4-59.dsl.wlfrct.sbcglobal.net (paulc@76.192.4.59 with login) by smtp101.sbc.mail.ac4.yahoo.com with SMTP; 28 Mar 2010 11:27:48 -0700 PDT X-Yahoo-SMTP: .XXmOBOswBCkuxW404eTLsnd.RdCQPge3WAF X-YMail-OSG: xNHr3mIVM1k1vBmVRmQ0vDJALWwEXHkRikQnFwauVJWR.VtqR69r5b83Vk.3JjU6V6a6XEjrMU6EAidtchryqAjG2thr.JJRFr6CfxblmLyZlgXa3T3XntaOhLIo_pWzHAcSldAIz_qXCKqL72Ocfb5qACmZT5QFyOl8xg_mckdR6MB0CRDrPnw1VZzxhyL.pkBIuY4QTVlVyeXlsLMj_LGKWF5zOJxIG7Csw0kz6um13wtUHqdrFU2jJ3Sbka0z0fkheXsMOQzVmP6Vg6lqbciJAND4wkfdnIadOz6q7bgWBe_fC8z_QBexRgzjWnsmSky6dav6wadxdNPG3VOH.LKN X-Yahoo-Newman-Property: ymail-3 From: "Paul A. Cianciolo" To: Date: Sun, 28 Mar 2010 14:27:52 -0400 Message-ID: MIME-Version: 1.0 X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) Importance: Normal X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-MS-TNEF-Correlator: In-Reply-To: <38A51B74B884D74083D7950AD0DD85E82A1BAC@File-Server-HST.hst.e-technik.tu-darmstadt.de> DomainKey-Status: good (testing) X-Spam-Score: 0.9 (/) X-Spam-Report: autolearn=disabled,DNS_FROM_RFC_WHOIS=0.879,HTML_MESSAGE=0.001,UNPARSEABLE_RELAY=0.001 Subject: RE: LF: Question about ground impedance at 8.97 KHZ **UPDATE Content-Type: multipart/mixed; boundary="----=_NextPart_000_006B_01CACE82.D9A88210" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_20_30,HTML_FONTCOLOR_BLUE, HTML_MESSAGE 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-global-disposition: G X-AOL-VSS-INFO: 5400.1158/56817 X-AOL-VSS-CODE: clean x-aol-sid: 3039ac1d411a4baf9ff82fe6 X-AOL-IP: 193.82.116.20 ------=_NextPart_000_006B_01CACE82.D9A88210 Content-Type: multipart/alternative; boundary="----=_NextPart_001_006C_01CACE82.D9A88210" ------=_NextPart_001_006C_01CACE82.D9A88210 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable RE: LF: Question about ground impedance at 8.97 KHZ **UPDATEHello Stef= an, Thank you for the response. I hope to increase the "C" with top wires= ? The coil I have calculated is very large as you say.=20 Using one of Reg Edwards programs, it appears that a coil 1.2 meters= tall, .6 meters in diameter, using #21 wire, .76 MM dia would result in a 54= 5 mHy inductor. It would take 1500 turns, have a dc res. of 110 ohms and consist of 93= 00' of wire for a total of 23 lbs of copper. I chose #21 because of the its= larger than the .46 MM you uses and hopefully would yield a higher "Q" and because I found a 50 LBs spool in possession already helps also.= :>) The predicted "Q" of the inductor is 300. I have to read more about tophat/wires at 9 KHz, but anything that wou= ld reduce the size of the coil would be helpful. PauLC W1VLF =20 -----Original Message----- From: Stefan Sch=E4fer [mailto:owner-rsgb_lf_group@blacksheep.org]On= Behalf Of Stefan Sch=E4fer Sent: Saturday, March 27, 2010 7:23 PM To: rsgb_lf_group@blacksheep.org Subject: AW: LF: Question about ground impedance at 8.97 KHZ **UPDATE Paul, the values you measured seem to be realistic for me. Especiall= y the measured antenna C does not really differ very much between 137kHz and= 9 kHz. It is a good value that allows you to dimension your needed L. Th= e needed L is nearly independent from the earth losses. I generally reco= mmend a variometer part of 1...5% of the fixed L to compensate all effects= that influence the antenna C. But think about if it is possible to increase= the antenna C instead of building a very huge coil that causes further los= ses. Good luck and have fun with building up! :-) 73, Stefan/DK7FC ----------------------------------------------------------------------= ------ -- Von: owner-rsgb_lf_group@blacksheep.org im Auftrag von Paul A. Cianc= iolo Gesendet: Sa 27.03.2010 22:01 An: rsgb_lf_group@blacksheep.org Betreff: RE: LF: Question about ground impedance at 8.97 KHZ **UPDAT= E Hello Folks, Thank you for all the help with measuring my antenna impedance. Let me explain further what I was using to measure with and then add= some updates. The homebrew bridge I was using was built as the one in the followin= g link. The diagram at the very bottom of the page is the schematic I used. http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=3D2285 This really my first venture into things LF and I had really no idea= of what to expect for numbers After posting my results here, and talking to W1VD, he forwarded me= a link to Alan and Finbar's bridge experiments here http://www.alan.melia.btinternet.co.uk/aelossbr.htm Basically I duplicated that design, making sure that the transformer= had 100 mHy of inductance to work at 10 KHz. Sure enough the bridge worked, and balance with my antenna, but woul= d not balance with my antenna simulator load. The simulated load is 2 X 390 ohm .1% resistors in series with a 500= pf silver mica. Reading on Alan talks about stray capacitance. "The problem with the usual trifilar wound transformer is that if dr= iven from an unbalanced source the secondary suffers unbalanced strays to= ground. This would mean that if you were to swap the components on the arms of= the bridge the balance would be different" With that in mind I built another transformer to balance the drive= to the bridge. After doing this the bridge will now balance with the simulat= ed load and the antenna. See the following numbers for results: Measurments were taken 10Khz The "R" and "C" "known" side of the bridge were then measure measure= d Sim load =3D 780 Ohms and 507 PF on LCR meter Sim load =3D 940 Ohms and 460 pf on the bridge. Antenna =3D 1111 Ohms and 330 PF on bridge Antenna also measured at 137 KHz Antenna =3D 85 ohms and 340 pf @137 Khz. I think these are more in line with what I should be reading???? What do you folks think? Thank you to everyone who responded to this post and helping me get started. PauL C W1VLF -----Original Message----- From: owner-rsgb_lf_group@blacksheep.org [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Johan H. Bod= in Sent: Friday, March 26, 2010 4:32 PM To: rsgb_lf_group@blacksheep.org Subject: Re: LF: Question about ground impedance at 8.97 KHZ Stefan. Hi Paul, it sounds like your impedance bridge is measuring the absolute imped= ance (that is Z =3D (R^2 + X^2)^0.5 where R is the real part, resistance,= and X is the imaginary part, reactance). R is probably a 10 to a few hundr= ed ohms, most of it is ground resistance - it can be neglected - the ma= jor part of your impedance is the capacitive reactance of the antenna (X= c). At 9 kHz, where C =3D 1/(2*Pi*9000*Xc), 70 kOhms means 253pF which= is in the ballpark for your 170' wire (about 5pF/m). 73 Johan SM6LKM ---- Paul A. Cianciolo wrote: > > Hello All, > > Below is a quote from the Stefan's web page concerning his latest "Dreamers Band" DX contact Congratulations again Stefan. >>From this information alone is it possible to calculate or know th= e antenna system impedance. > > > > > "100m Vertical wire antenna, coil/antenna voltage was abt 15kV rms= , average antenna current about 480mA, giving up to 1,7mW ERP. Applied= power was up to 250W." > > Pertaining to the coil "Technical and mechanical data: L=3D553mH,= Q=3D82, R(DC)=3D283 Ohm; 0,4mm diameter enameled copper wire, about 1200 turns= ! Average diameter 0,55m, height abt 0,5m. So, about 2000m wire! :-)" > > > > I have built a small impedance bridge that operates at 10 KHZ and= shows my sloping 170' wire as 70K Ohms. I can also see approx 500 PF that ca= n be nulled out using the bridge? > > Can the 70K value possibly be correct? (3) 6' ground rods about= 6' apart are the ground... plus the electrical ground of the house. > > I am hoping to attempt a local transmission on 9KHZ > > Any information would be helpful. > > Thank you > > Paul > > W1VLF > > > > > ------=_NextPart_001_006C_01CACE82.D9A88210 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable RE: LF: Question about ground impedance= at 8.97 KHZ **UPDATE
H= ello=20 Stefan,
 
T= hank you for the=20 response.  I hope to increase the "C" with top wires?
 
T= he coil I have=20 calculated is very large as you say.
Using one of Reg Edward= s programs, it appears=20 that a coil 1.2 meters tall, .6 meters in diameter, using #21 wire, .7= 6 MM dia=20 would result in a 545 mHy inductor.
I= t would take=20 1500 turns, have a dc res. of 110 ohms and consist of 9300' of wire fo= r a total=20 of 23 lbs of copper.  I chose #21 because of the its larger than= the .46=20 MM you uses and hopefully= would yield=20 a higher "Q"
and because  I fou= nd a 50 LBs spool in=20 possession already helps also. :>)= =20   The predicted "Q" of the inductor is=20 300.
 
I have to read more about tophat/wir= es at 9 KHz, but=20 anything that would reduce the size of the coil would be=20 helpful.
 
PauLC
W1VLF<= /DIV>
 
 
 
 
 
 
 -----Original Message-----
From:=20 Stefan Sch=E4fer [mailto:owner-rsgb_lf_group@blacksheep.org]On Beha= lf Of=20 Stefan Sch=E4fer
Sent: Saturday, March 27, 2010 7:23=20 PM
To: rsgb_lf_group@blacksheep.org
Subject: AW:= LF:=20 Question about ground impedance at 8.97 KHZ=20 **UPDATE

Paul, the= values you=20 measured seem to be realistic for me. Especially the measured antenn= a C does=20 not really differ very much between 137kHz and 9 kHz. It is a good= value that=20 allows you to dimension your needed L. The needed L is nearly= independent=20 from the earth losses. I generally recommend a variometer part of 1.= ..5% of=20 the fixed L to compensate all effects that influence the antenn= a C. But=20 think about if it is possible to increase the antenna C instead of= building a=20 very huge coil that causes further losses.
 
Good luck and have fun wi= th building up!=20 :-)
 
73, Stefan/DK7FC

Von: owner-rsgb_lf_group@blacksh= eep.org im=20 Auftrag von Paul A. Cianciolo
Gesendet: Sa 27.03.2010=20 22:01
An: rsgb_lf_group@blacksheep.org
Betreff:= RE: LF:=20 Question about ground impedance at 8.97 KHZ **UPDATE

<= /DIV>

Hello Folks,

Thank you for all the help wit= h measuring=20 my antenna impedance.

Let me explain further what I was using= to=20 measure with and then add some updates.
The homebrew bridge I was= using was=20 built as the one in the following link.
The diagram at the very= bottom of=20 the page is the schematic I used.
http://www.dxzone.com/cgi-bin/d= ir/jump2.cgi?ID=3D2285

This=20 really my first venture into things LF and I had really no idea of= what to=20 expect for numbers
After posting my results here, and talking to= W1VD, he=20 forwarded me a link to Alan and Finbar's bridge experiments here
= ht= tp://www.alan.melia.btinternet.co.uk/aelossbr.htm

Basically= =20 I duplicated that design, making sure that the transformer had 100= mHy of=20 inductance to work at 10 KHz.
Sure enough the bridge worked, and= balance=20 with my antenna, but would not balance with my antenna simulator=20 load.

The simulated load is 2 X 390 ohm .1% resistors in seri= es with a=20 500 pf silver mica.

Reading on Alan talks about stray=20 capacitance.

"The problem with the usual trifilar wound trans= former is=20 that if driven from an unbalanced source the secondary suffers unbal= anced=20 strays to ground. This would mean that if you were to swap the compo= nents on=20 the arms of the bridge the balance would be different"

With= that in=20 mind I built another transformer to balance the drive to the bridge.=  =20 After doing this the bridge will now balance with the simulated load= and the=20 antenna.
See the following numbers for results:

Measurment= s were=20 taken 10Khz
The "R" and "C" "known" side of the bridge were then= measure=20 measured

Sim load =3D  780 Ohms and  507 PF on = ; LCR=20 meter

Sim load =3D  940 Ohms and  460 pf  on= the=20 bridge.


Antenna =3D  1111 Ohms and 330 PF on=20 bridge

Antenna also measured at 137 KHz

Antenna =3D 85= ohms and=20 340 pf @137 Khz.


I think these are more in line with what= I should=20 be reading????

What do you folks think?

Thank you to= everyone=20 who responded to this post and helping me get started.


Pa= uL=20 C
W1VLF












-----O= riginal=20 Message-----
From: owner-rsgb_lf_group@blacksheep.org
[mailto:owner-rsgb= _lf_group@blacksheep.org]On=20 Behalf Of Johan H. Bodin
Sent: Friday, March 26, 2010 4:32 PM
= To:=20 rsgb_lf_group@blacksheep.org
Subject: Re: LF: Question about grou= nd=20 impedance at 8.97 KHZ Stefan.


Hi Paul,

it sounds= like your=20 impedance bridge is measuring the absolute impedance
(that is Z= =3D (R^2 +=20 X^2)^0.5 where R is the real part, resistance, and X
is the imagi= nary part,=20 reactance). R is probably a 10 to a few hundred
ohms, most of it= is ground=20 resistance - it can be neglected - the major
part of your impedan= ce is the=20 capacitive reactance of the antenna (Xc).
At 9 kHz, where C =3D= =20 1/(2*Pi*9000*Xc), 70 kOhms means 253pF which is in
the ballpark= for your=20 170' wire (about 5pF/m).

73
Johan SM6LKM

----
Paul A.=20 Cianciolo wrote:
>
> Hello All,
>
> Below is= a quote=20 from the Stefan's web page concerning his latest "Dreamers Band" DX= contact=20 Congratulations again Stefan.
>>From this information alone= is it=20 possible to calculate or know the antenna system=20 impedance.
>
>
>
>
> "100m Vertical wi= re=20 antenna, coil/antenna voltage was abt 15kV rms, average antenna curr= ent about=20 480mA, giving up to 1,7mW ERP. Applied power was up to 250W."
>= ;
>=20 Pertaining to the coil "Technical and mechanical data: L=3D553mH, Q= =3D82,=20 R(DC)=3D283 Ohm; 0,4mm diameter enameled copper wire, about 1200 tur= ns! Average=20 diameter 0,55m, height abt 0,5m. So, about 2000m wire!=20 :-)"
>
>
>
> I have built a small impedance= bridge=20 that operates at 10 KHZ and shows my sloping 170' wire as 70K Ohms.= I can also=20 see approx 500 PF that can be nulled out using the bridge?
>> Can=20 the 70K value possibly be correct?   (3) 6' ground rods ab= out 6'=20 apart are the ground... plus the electrical ground of the=20 house.
>
> I am hoping to attempt a local transmission= on=20 9KHZ
>
> Any information would be helpful.
>
&g= t; Thank=20 you
>
> Paul
>
>=20 W1VLF
>
>
>
>
>


=
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