Return-Path: Received: from mtain-di12.r1000.mx.aol.com (mtain-di12.r1000.mx.aol.com [172.29.64.16]) by air-db06.mail.aol.com (v129.4) with ESMTP id MAILINDB063-86484c7e8270291; Wed, 01 Sep 2010 12:42:24 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-di12.r1000.mx.aol.com (Internet Inbound) with ESMTP id 9FA48380000B1; Wed, 1 Sep 2010 12:42:22 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OqqMQ-0003cb-Mv for rs_out_1@blacksheep.org; Wed, 01 Sep 2010 17:40:30 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OqqMQ-0003cS-4a for rsgb_lf_group@blacksheep.org; Wed, 01 Sep 2010 17:40:30 +0100 Received: from mail-qw0-f43.google.com ([209.85.216.43]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OqqMK-0001ZD-JN for rsgb_lf_group@blacksheep.org; Wed, 01 Sep 2010 17:40:30 +0100 Received: by qwb7 with SMTP id 7so52268qwb.16 for ; Wed, 01 Sep 2010 09:40:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=YJQnnKmUY/TppMSUpEqITRYy80ounY45o1l47DfbOXw=; b=Ja6IGf7VpHs4xzlBhMwq8Uf5tYzM4AQNQcjDeBYorSY0v3rnQ8Nq1JgSky2X8ssgHE HqpFgOraF/QZ7//+3J+wgqcXaIytNGPEqB6LukGDKoTHApoFaSc4k3iHVLL4nHPHcLZ1 G2a81FSH7MNDbaS6EDEYzXeUinLGRUNCUABIY= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=H1jo149RWe0rZ4ZxYN58gVtswLlXYhdgV9JMaxUpjFRXk+rnJm11/enacG5K9Xii1l WSjwsdw6kXAyuosx6pGsHvUggJr9V1yqlw/2sfayeIYhIorwRMn9Xam0H1HAtfjwJ5iq C+TxD3h4A5dJu0r6/gRWQd+r5KQCg7rfQJO0w= MIME-Version: 1.0 Received: by 10.224.65.95 with SMTP id h31mr5380017qai.116.1283359208915; Wed, 01 Sep 2010 09:40:08 -0700 (PDT) Received: by 10.229.238.147 with HTTP; Wed, 1 Sep 2010 09:40:08 -0700 (PDT) In-Reply-To: <002501cb49f0$acabccb0$0401a8c0@xphd97xgq27nyf> References: <000a01cb493d$fb8f3410$0401a8c0@xphd97xgq27nyf> <4C7E2046.536.2C4F91@v.d.heide.on-line.de> <002501cb49f0$acabccb0$0401a8c0@xphd97xgq27nyf> Date: Wed, 1 Sep 2010 12:40:08 -0400 Message-ID: From: Warren Ziegler To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: VLF THOUGHT Content-Type: multipart/alternative; boundary=00c09f899228c469ab048f3559a7 X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d254.1 ; domain : gmail.com DKIM : pass x-aol-sid: 3039ac1d40104c7e826e0d38 X-AOL-IP: 193.82.116.20 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --00c09f899228c469ab048f3559a7 Content-Type: text/plain; charset=ISO-8859-1 Mal, You seem to be intent on ignoring the basic physics. An 8.97Kcs audio tone is attenuated at 130dB/km. You are proposing concentrating the sound in one direction, analogous to a directive antenna, still with say 10kW and an 'antenna' (actually speaker directivity) gain of say 30dB you would start out with effectively 10MW, but with 130dB/km you would be down to 1 microwatt at a distance of 1km !!! Ten MEGAWATTS becomes 1 MICROWATT after 1km at 8.97 kHz!!! Case closed! On Wed, Sep 1, 2010 at 12:13 PM, mal hamilton wrote: > With all the energy concentrated into a single tone on 8.97 Kcs it could > well travel a considerable distance with a few Kilowatts of audio beamed > in an arranged direction, especially along a valley. > I am surprised that the high voltage 50 Hz electricity > overhead distribution network is not heard over great distances by ear. > > g3kev > > > ----- Original Message ----- > *From:* Warren Ziegler > *To:* rsgb_lf_group@blacksheep.org > *Sent:* Wednesday, September 01, 2010 3:31 PM > *Subject:* Re: LF: VLF THOUGHT > > Rik, > > Krakatoa exploded with the equivalent force of 200 Megatons of TNT, > bigger than the largest Hydrogen bomb and 13,000 times the size of the > nuclear explosion that destroyed Hiroshima. > > That said, I believe that what was hear at a distance was still the low > frequency rumble, 100Hz is attenuated at only 0.3dB/km while 10kHz is > attenuated over 150dB/km. > > Best to stick with EM waves as opposed to sound. > > - > 73 Warren K2ORS > WD2XGJ > WD2XSH/23 > WE2XEB/2 > WE2XGR/1 > > On Wed, Sep 1, 2010 at 3:58 AM, Rik Strobbe wrote: > >> All, >> >> here some real "DX":The explosion of the Krakatoa (1883) was heard in >> Perth (Australia), 3100 km away, and on the island of Rodrigues, 5000 km >> away. >> >> 73, Rik ON7YD >> ________________________________________ >> Van: owner-rsgb_lf_group@blacksheep.org [ >> owner-rsgb_lf_group@blacksheep.org] namens Klaus von der Heide [ >> v.d.heide@on-line.de] >> Verzonden: woensdag 1 september 2010 9:43 >> Aan: rsgb_lf_group@blacksheep.org >> Onderwerp: Re: LF: VLF THOUGHT >> >> Hello All, >> >> >> two years ago someone disturbed my breakfast by a deeply >> hammering disco sound. So I took my car to search for >> the source. Surprisingly, the sound decreased to nearly >> zero when I drove some kilometers in that direction where >> the sound seem to come from. The Odyssey took 45 minutes. >> But finally I found the open-air disco 20 km from my home >> in a lonely wood. >> >> Indeed, the sound took nearly 60 seconds from there to my >> home. That's more than a thunder usually reaches. >> >> More than thousand square-kilometers where contaminated, >> including 23 protected nature resevats. >> >> Yes we can, but Mankind should not do everything what it can. >> >> >> 73! >> >> Klaus, DJ5HG >> > > > > - > > > -- 73 Warren K2ORS WD2XGJ WD2XSH/23 WE2XEB/2 WE2XGR/1 --00c09f899228c469ab048f3559a7 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Mal,

=A0=A0 =A0You seem to be intent on ignoring the ba= sic physics.=A0

An 8.97Kcs audio tone is attenuat= ed at 130dB/km.=A0

You are proposing concentratin= g the sound in one direction, analogous to a directive antenna, still with= say 10kW and an 'antenna' (actually speaker directivity) =A0gain= of say 30dB you would start out with effectively 10MW, but with 130dB/km= you would be down to 1 microwatt at a distance of 1km !!!=A0

Ten MEGAWATTS becomes 1 MICROWATT after 1km at 8.97 kH= z!!!

Case closed!



= On Wed, Sep 1, 2010 at 12:13 PM, mal hamilton <g3kevmal@talktalk.net> wr= ote:
With all the energy concentrated into= a single tone=20 on=A08.97 Kcs =A0it could well travel a considerable distance with a few= =20 Kilowatts of audio=A0beamed in=A0an arranged direction, especially along= a=20 valley.
I am surprised that the high voltage= 50 Hz=20 electricity overhead=A0distribution network is not heard over great distan= ces=20 by ear.
=A0
g3kev
=A0
----- Original Message -----
From:=20 Warren Ziegler=20
Sent: Wednesday, September 01, 201= 0 3:31=20 PM
Subject: Re: LF: VLF THOUGHT

Rik,

=A0=A0 Krakatoa exploded with the equivalent force of 200 Megatons= =20 of TNT, bigger than the largest Hydrogen bomb and 13,000 times the size= of the=20 nuclear explosion that destroyed Hiroshima.
=A0
=A0=A0 That said, I believe that what was hear at a distance was=20 still the low frequency rumble, 100Hz is attenuated at only 0.3dB/km whi= le=20 10kHz is attenuated over 150dB/km.

Best to stick with EM waves as opposed to sound.

-=A0
73 Warren K2ORS
=A0 =A0 =A0 =A0 =A0 =A0=20 =A0 =A0 WD2XGJ=A0
=A0 =A0 =A0 =A0 =A0 =A0 =A0=20 =A0 WD2XSH/23
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=20 WE2XEB/2
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=20 WE2XGR/1

On Wed, Sep 1, 2010 at 3:58 AM, Rik Strobbe= <Rik.Strobbe@fys.kuleuven.be>=20 wrote:
All,

here=20 some real "DX":The explosion of the Krakatoa (1883) was hear= d in Perth=20 =A0(Australia), 3100 km away, and on the island of Rodrigues, 5000 km= =20 away.

73, Rik=20 =A0ON7YD
________________________________________
Van: owner-rsg= b_lf_group@blacksheep.org=20 [owner-rsgb_lf_group@blacksheep.org]=20 namens Klaus von der Heide [v.d.heide@on-line.de]
Verzonden:=20 woensdag 1 september 2010 9:43
Aan: rsgb_lf_group@blacksheep.org
Ond= erwerp:=20 Re: LF: VLF THOUGHT

Hello All,


two years ago someone disturbed my=20 breakfast by a deeply
hammering disco sound. So I took my car to se= arch=20 for
the source. Surprisingly, the sound decreased to nearly
zero= when=20 I drove some kilometers in that direction where
the sound seem to= come=20 from. The Odyssey took 45 minutes.
But finally I found the open-air= disco=20 20 km from my home
in a lonely wood.

Indeed, the sound took= nearly=20 60 seconds from there to my
home. That's more than a thunder us= ually=20 reaches.

More than thousand square-kilometers where=20 contaminated,
including 23 protected nature resevats.

Yes we= can,=20 but Mankind should not do everything what it=20 can.


73!

Klaus,=20 DJ5HG



-
= =A0



--
73 Warren K2ORS
=A0= =A0 =A0 =A0 =A0 =A0 =A0 =A0 WD2XGJ
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 WD= 2XSH/23
=A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 WE2XEB/2
=A0 =A0 =A0 =A0 =A0= =A0 =A0 =A0 WE2XGR/1

=A0
--00c09f899228c469ab048f3559a7--