Return-Path: Received: from mtain-mc08.r1000.mx.aol.com (mtain-mc08.r1000.mx.aol.com [172.29.96.80]) by air-df02.mail.aol.com (v127_r1.1) with ESMTP id MAILINDF021-5ee64b976ae93e6; Wed, 10 Mar 2010 04:48:25 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-mc08.r1000.mx.aol.com (Internet Inbound) with ESMTP id C2D17380000C2; Wed, 10 Mar 2010 04:48:23 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NpIVG-0000yl-P3 for rs_out_1@blacksheep.org; Wed, 10 Mar 2010 09:46:58 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NpIVG-0000yc-7z for rsgb_lf_group@blacksheep.org; Wed, 10 Mar 2010 09:46:58 +0000 Received: from web28103.mail.ukl.yahoo.com ([217.146.182.123]) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1NpIVG-0001Mg-4A for rsgb_lf_group@blacksheep.org; Wed, 10 Mar 2010 09:46:58 +0000 Received: (qmail 95084 invoked by uid 60001); 10 Mar 2010 09:46:50 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yahoo.co.uk; s=s1024; t=1268214410; bh=tG+Tqc1K4mVx+MANlSyonkG16v2wfOdvSM27bDiW5ag=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=mReL0lYTGCxvHKDkUpYXi/mJnRu4BGbVUhEzkaWlWqEnONzJEVF0ExbCaSPxmaCUNf3MQ+BMD9jkhyy6AocWVvGG+/TS74C9bIH73yM+kecXB7FYCr4Fg0X0o5uMIyxJlAG+4G/oOEBhet6AfGFJClVwZfBepE5EIdN8AQ98bms= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.co.uk; h=Message-ID:X-YMail-OSG:Received:X-Mailer:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=NuuvCpw2hgsysyzUNCVLgLMxN1us56UXyg9MgqhayQDcwnTike16JAvRpwK6SuXu85VWcSTImWB5zKdP007p/eRQTUnImm3FdRPzQNNZ/XMxljXVfKEzK4JTdFf7RdvjX5SAqyJCPNMUMCmvaDhLkYul31GIGI8jGCOTD7QQr4g=; Message-ID: <629829.94807.qm@web28103.mail.ukl.yahoo.com> X-YMail-OSG: ckb9XNQVM1lEPBTIWJkIwjmH6TuqCvgEbSEsXF6m3t4tT6Q KWP74sFuENQGBseOdSv6_B0OG_dRpg77sJ3ryHPj_FYMp3W2CR1cjc3oC0Ej X7JmKjar3o8e9EZD_roatzxo69g8epHwQ07pYUTTOgJRrObFYye1q3n27Ee7 U0pZKmUZAvxVZRPITqxsJJBbI2RdyNZT1rjfE5u7pUSdtOXGDTtqbESfiS_H pvewNJvNdY0y3ifVJrU3GmtP_HADLLoIwk9cxfC_nx2A8OA-- Received: from [81.152.21.211] by web28103.mail.ukl.yahoo.com via HTTP; Wed, 10 Mar 2010 01:46:50 PST X-Mailer: YahooMailClassic/9.2.12 YahooMailWebService/0.8.100.260964 Date: Wed, 10 Mar 2010 01:46:50 -0800 (PST) From: M0FMT To: rsgb_lf_group@blacksheep.org In-Reply-To: <4B96F744.60703@abelian.org> MIME-Version: 1.0 DomainKey-Status: good (testing) Subject: Re: LF: Exciter and VLF TX coil matching Content-Type: multipart/alternative; boundary="0-606252421-1268214410=:94807" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.1 required=5.0 tests=HTML_MESSAGE, MAILTO_TO_SPAM_ADDR 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-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m236.2 ; domain : yahoo.co.uk DKIM : pass x-aol-sid: 3039ac1d60504b976ae77dff X-AOL-IP: 193.82.116.20 --0-606252421-1268214410=:94807 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Hi Group =A0 Dr Steve Myers, a director of the European Organization for Nuclear Resear= ch (CERN), which built the collider, said the machine will close at the en= d of a 2011.=20 The collider is expected to reach world record power later this month at= 7 trillion electron volts (TeV) in its bid to replicate the big bang that= started the universe. =A0 Now thats what I call a 8.9kc/s dream band exciter!!!! 73 es GL petefmt --- On Wed, 10/3/10, Paul Nicholson wrote: From: Paul Nicholson Subject: Re: LF: VLF TX coil matching To: rsgb_lf_group@blacksheep.org Date: Wednesday, 10 March, 2010, 1:35 Stefan Sch=E4fer schrieb: > Who tells that they [charge] are just to find at the end? The charge distributes itself for minimum potential energy, so it concentrates somewhat towards the ends.=A0 Actually the concentration isn't all that much, only about 10% greater at the bottom end than in the center. http://abelian.org/vlf/tmp/ss100309a.png shows the linear charge density, Coulombs/metre, along the wire having 1 volt on it.=A0 At least that's what the model says, I will have to check it against Maxwell's 1878 formula! The distribution is slightly biased towards the bottom due to the presence of the ground, so the effective height will be a bit less than h/2. The maximum surface field strength looks to be about 2.2 volts/cm per volt on the wire, ie 10kV on the wire will give you 22kV/cm at the bottom end of the wire.=A0 Take these results with a 'pinch of salt' until I've checked the model against some calculation.=A0=A0=A0But the figures look reasonable and if they stand, there is no problem until 20-30kV, and then you can suppress corona easily with rings and spheres. > I plan to use an inductive coupled primary coil, OK.=A0 There is some advantage to driving into the base, as Markus mentioned in a post a few days ago - current is self limiting as the system detunes.=A0 You would need up to a kV from the driver, I think.=A0=A0=A0If you can't manage that, it would have to be a tuned primary. > The PA has a big output transformer with different numbers > of turns, like a universal transformer. Perfect. > do you think i MUST have to built a simple band pass? No, not yet.=A0 Still running models.=A0 For example, first overtone is at 117kHz, close to 13th drive harmonic.=A0 Coil base impedance is quite high and harmonic voltage 1/13th of fundamental so current is low.=A0 But low enough to ignore?=A0 Not sure yet. That's with a square wave from a switching driver straight into the base.=A0 Maybe a broadly tuned primary (Q=3D10) will be needed? Or just a simple trap to catch and dump the high harmonics into a resistor?=A0 Basic question is: can loading coil Q at 9kHz be relied upon for a clean signal when directly driven from a simple efficient switch-mode PA?=A0=A0=A0Yes, Q is high but the coil is a transmission line and has a spectrum of resonances... > Each friday and monday i have free time, so my weekend > is 4 days! I will move to Heidelberg too :) -- Paul Nicholson -- =20 --0-606252421-1268214410=:94807 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
Hi Group
 
Dr Steve Myers, a director of the European Organization for Nuclear= Research (CERN), which built the collider, sai= d the machine will close at the end of a 2011.
The collider is expected to reach world record power later this month= at 7 trillion electron volts (TeV) in its bid to= replicate the big bang that started the universe.
 
Now thats what I call a 8.9kc/s dream band exciter!!!!

73 es= GL petefmt

--- On Wed, 10/3/10, Paul Nicholson <vlf0308@a= belian.org> wrote:

From: Paul Nicholson <vlf0308@abelian.org&g= t;
Subject: Re: LF: VLF TX coil matching
To: rsgb_lf_group@blackshee= p.org
Date: Wednesday, 10 March, 2010, 1:35

Stefan Sch=E4fer schrieb:

> Who tells tha= t they [charge] are just to find at the end?

The charge distributes= itself for minimum potential energy,
so it concentrates somewhat towar= ds the ends.  Actually
the concentration isn't all that much, only= about 10% greater
at the bottom end than in the center.

http://abeli= an.org/vlf/tmp/ss100309a.png

shows the linear charge density,= Coulombs/metre, along the
wire having 1 volt on it.  At least tha= t's what the model
says, I will have to check it against Maxwell's 1878= formula!

The distribution is slightly biased towards the bottom du= e
to the presence of the ground, so the effective height will
be a= bit less than h/2.

The maximum surface field strength looks to be= about 2.2
volts/cm per volt on the wire, ie 10kV on the wire will
g= ive you 22kV/cm at the bottom end of the wire.  Take these
results with a 'pinch of= salt' until I've checked the model
against some calculation. &nbs= p; But the figures look reasonable
and if they stand, there is no= problem until 20-30kV, and
then you can suppress corona easily with ri= ngs and spheres.

> I plan to use an inductive coupled primary co= il,

OK.  There is some advantage to driving into the base, as<= BR>Markus mentioned in a post a few days ago - current is self
limiting= as the system detunes.  You would need up to a
kV from the driver= , I think.   If you can't manage that,
it would have to= be a tuned primary.

> The PA has a big output transformer with= different numbers
> of turns, like a universal transformer.

= Perfect.

> do you think i MUST have to built a simple band pass?=

No, not yet.  Still running models.  For example, first overtone
is at 117kHz, close to 13th drive harmonic.  Coil base= impedance
is quite high and harmonic voltage 1/13th of fundamental
= so current is low.  But low enough to ignore?  Not sure yet.
= That's with a square wave from a switching driver straight into
the bas= e.  Maybe a broadly tuned primary (Q=3D10) will be needed?
Or just= a simple trap to catch and dump the high harmonics into
a resistor?&nb= sp; Basic question is: can loading coil Q at 9kHz be
relied upon for a= clean signal when directly driven from a simple
efficient switch-mode= PA?   Yes, Q is high but the coil is a
transmission lin= e and has a spectrum of resonances...

> Each friday and monday= i have free time, so my weekend
> is 4 days!

I will move to= Heidelberg too :)
--
Paul Nicholson
--


=20 --0-606252421-1268214410=:94807--