Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 7867F38000095; Sun, 2 Oct 2011 19:00:29 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1RAV0P-0007za-LK for rs_out_1@blacksheep.org; Sun, 02 Oct 2011 23:59:33 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1RAV0O-0007zR-Td for rsgb_lf_group@blacksheep.org; Sun, 02 Oct 2011 23:59:32 +0100 Received: from smtp5.freeserve.com ([193.252.22.152]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1RAV0M-0005u7-5Y for rsgb_lf_group@blacksheep.org; Sun, 02 Oct 2011 23:59:32 +0100 Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3421.me.freeserve.com (SMTP Server) with ESMTP id 787341C0009C for ; Mon, 3 Oct 2011 00:59:24 +0200 (CEST) Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3421.me.freeserve.com (SMTP Server) with ESMTP id 6B50C1C0009E for ; Mon, 3 Oct 2011 00:59:24 +0200 (CEST) Received: from AGB (unknown [2.26.46.95]) by mwinf3421.me.freeserve.com (SMTP Server) with SMTP id 2A71F1C0009C for ; Mon, 3 Oct 2011 00:59:24 +0200 (CEST) X-ME-UUID: 20111002225924174.2A71F1C0009C@mwinf3421.me.freeserve.com Message-ID: From: "Graham" To: References: <001401cc80dd$21b80ea0$0401a8c0@xphd97xgq27nyf> <002001cc80ed$f37be7d0$0401a8c0@xphd97xgq27nyf> <005301cc811a$c14eee10$0401a8c0@xphd97xgq27nyf> <4E88E56C.9030602@toya.net.pl> In-Reply-To: <4E88E56C.9030602@toya.net.pl> Date: Sun, 2 Oct 2011 23:59:23 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 X-Antivirus: avast! (VPS 111002-2, 02/10/2011), Outbound message X-Antivirus-Status: Clean X-Spam-Score: 0.2 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RCVD_ILLEGAL_IP=0.234 Subject: Re: LF: Dreamers Content-Type: multipart/alternative; boundary="----=_NextPart_000_020E_01CC815F.4F4EC3E0" 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_20_30,HTML_MESSAGE, HTML_TITLE_EMPTY,MISSING_OUTLOOK_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-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:433925728:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d600d4e88ed0d5f01 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_020E_01CC815F.4F4EC3E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Top band dipole is ~~ 1 meter , anyone tried using one in the = local pond ?=20 Sonar target resolution and towed arrays next ? , dose say the = LF group ! G..=20 f =3D 8.97 kHz=20 lambda in a medium: 14.9 meters f =3D 82 Hz ( ZEVS)=20 lambda in a medium: 156 meters From: Piotr Mlynarski=20 Sent: Sunday, October 02, 2011 11:27 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Dreamers W dniu 2011-10-02 17:48, mal hamilton pisze:=20 IE Dreamers, alias snails es crocodiles. I suppose they do have something = in common, especially the operator who works mostly underground = following gas pipes and water pipes, and then gets confused at = roundabouts Keep smiling !! and come up for air except you are nuclear propelled g3kev Hello Roger, LF/VLF "Dreamers" .. i will also make a reference to your " underground work" though it will = be slightly different from Mal observations.... Very often the medium over which the radio wave propagates ( soil, sea = water) is regarded as a semiconducting uniform medium characterized by its dielectric permittivity and conductivity - for such a model rather = basic physics of dielectrics can be adopted. Therefore, we can use the concept of a complex dielectric permittivity = which results in a few simple eqns. from that equations we get some numbers which i would like to present here.=20 it is very likely that you already know those numbers/estimates but for = me some of them came as a sort of surprise..... Some introductory remarks: A wave propagating in a free space is = attenuated in a medium and is strongly shortened. We can define = so-called=20 "penetration depth" as a depth at wich the amplitude of radio-wave is e = times smaller (2.718...) than the amplitude in a free space ( reciprocal of attenuation factor)=20 Also , [it was the most interesting to me] , we can estimate ( = connection with Leontowicz conditions, boundary continuity eqns. etc..) = how many times the horizontal component of a wave electric field in a medium is greater than its vertical = counterpart. At the same time this quantity shows how many times the vertical component of E field in a free space is greater than = horizontal component of a free space E-field vector.=20 Finally the numbers.. for the sake of curiosity i took the salt water at first ( Mal was = talking something about nuclear drive/subs) :) eps(r) :81 and sigma ( conductivity of a salt water: 5 Siemens/m) of course, the sigma depends strongly of salinity sigma =3D 5 is just = a reasonable example=20 f =3D 136.172 kHz=20 lambda in a free space: 2201.6 meters lambda in a medium: 3.81 meters penetration depth: 0.61 meters H/V ratio in a medium: 812.7 f =3D 8.97 kHz=20 lambda in a free space: 33421.7 meters lambda in a medium: 14.9 meters penetration depth: 2.376 meters H/V ratio in a medium: 3166.5 f =3D 82 Hz ( ZEVS)=20 lambda in a free space: 3656 KILOmeters lambda in a medium: 156 meters penetration depth: 24.8 meters H/V ratio in a medium: 33118.0 and now the soil: i assumed epsilon(r) =3D 4 sigma =3D 0.003 S/m / it is supposed to be something between dry soil = and slightly wet/moistured or so.. / f =3D 136.172 kHz=20 lambda in a free space: 2201.6 meters lambda in a medium: 155.6 meters penetration depth: 25.0 meters H/V ratio in a medium: 19.9 f =3D 8.97 kHz=20 lambda in a free space: 33421.7 meters lambda in a medium: 609.2 meters penetration depth: 97.0 meters H/V ratio in a medium: 77.6=20 =20 73, = Piotr, sq7mpj =20 =20 ------=_NextPart_000_020E_01CC815F.4F4EC3E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
 
Top band  dipole  is  = ~~  1=20 meter  , anyone  tried using  one  in the  = local =20 pond  ?
 
Sonar target  resolution  = and =20 towed  arrays next  ? , dose  say  the  = LF  group=20 !
 
G..
 
 
f =3D 8.97 kHz=20
lambda in a medium: 14.9 meters
 
f =3D  82 Hz=20 ( ZEVS)
lambda in a medium: 156 meters

From: Piotr Mlynarski
Sent: Sunday, October 02, 2011 11:27 PM
To: rsgb_lf_group@blacksheep.org= =20
Subject: Re: LF: Dreamers

W dniu 2011-10-02 17:48, mal hamilton pisze:=20
IE
Dreamers, alias snails es crocodiles. I = suppose they do=20 have something in common, especially the operator who works mostly = underground=20 following gas pipes and water pipes, and then gets confused at=20 roundabouts
Keep smiling !! and come up for air except you = are=20 nuclear propelled
 
g3kev


Hello = Roger, LF/VLF=20 "Dreamers" ..

i will also make a reference to your " underground = work"=20 though it will be slightly different  from Mal = observations....

Very=20 often the medium over which the  radio wave propagates ( soil, sea = water)=20 is regarded as a semiconducting uniform medium characterized = by
 its=20 dielectric permittivity and conductivity - for such a model rather basic = physics=20 of dielectrics can be adopted.
Therefore, we can use the concept of a = complex=20 dielectric permittivity which results in a few simple eqns. from that=20 equations
 we get some numbers which i would like to present = here.=20
it is very likely that you already know those numbers/estimates but = for me=20 some of them came as a sort of surprise.....

Some introductory = remarks: A=20 wave propagating in a free space is attenuated in a medium and is = strongly=20 shortened. We can define so-called
"penetration depth" as a depth at = wich=20 the amplitude of radio-wave is e times smaller (2.718...) than the = amplitude in=20 a free space
( reciprocal of attenuation factor)
Also , [it was = the most=20 interesting  to me] , we can estimate ( connection with Leontowicz=20 conditions, boundary continuity eqns. etc..) how many times the = horizontal=20 component
of a wave  electric field  in a medium  is = greater=20 than its vertical counterpart. At the same time this quantity shows how = many=20 times
 the vertical component of E field in a free space is = greater than=20 horizontal component of a free space E-field vector.
Finally the=20 numbers..

for the sake of curiosity i took the salt water at = first ( Mal=20 was talking something about nuclear drive/subs) :)

eps(r) :81 and = sigma (=20 conductivity of a salt water: 5 Siemens/m)
 of course, the sigma = depends=20 strongly of salinity  sigma =3D 5 is just a reasonable example =

f =3D=20 136.172 kHz
lambda in a free space: 2201.6 meters
lambda in a = medium:=20 3.81 meters
penetration depth: 0.61 meters
H/V ratio in a medium:=20 812.7


f =3D 8.97 kHz
lambda in a free space: 33421.7=20 meters
lambda in a medium: 14.9 meters
penetration depth: 2.376=20 meters
H/V ratio in a medium: 3166.5



f =3D  82 Hz = ( ZEVS)=20
lambda in a free space: 3656 KILOmeters
lambda in a medium: 156=20 meters
penetration depth: 24.8 meters
H/V ratio in a medium:=20 33118.0

and now  the soil:

 i assumed epsilon(r) = =3D=20 4
 sigma =3D 0.003 S/m  / it is supposed to be something = between dry=20 soil and slightly wet/moistured  or so.. /

f =3D 136.172 kHz =
lambda in a free space: 2201.6 meters
lambda in a medium: 155.6=20 meters
penetration depth: 25.0 meters
H/V ratio in a medium: = 19.9

f=20 =3D 8.97 kHz
lambda in a free space: 33421.7 meters
lambda in a = medium:=20 609.2 meters
penetration depth: 97.0 meters
H/V ratio in a medium: = 77.6=20

         =20
           &nb= sp;           &nbs= p;            = ;            =             &= nbsp;    =20 73, Piotr,=20 sq7mpj

          = ;            = =20
 

=
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